Tensegrity Wiki Blogspot

Kurilpa Bridge Analyzed

2011-11-10T04:24:00.000-08:00

Phil "Floating Bones" Earnhardt sent the following great link, I forward and expand on it a bit:

Oasys Software markets a series of products used for the design of buildings, bridges, retaining
walls, and other structures. They publish a variety of case studies on their website at http://www.oasys-software.com/solutions/case-studies.html . The studies cover noteworthy structures from around the world including The Beijing National Aquatic Centre (the "Water Cube") and The Singapore Marina Bay Sands Resort. It's a wonderful website with beautiful images and some cool math.

Of interest to us is their report on The Brisbane Kurilpa Bridge, winner of the World’s Best Transport Building award at the World Architecture Festival 2011 Awards. detailing the structural role of its tensegrity-like network of struts and cables. They confirm that the bridge is not a tensegrity, but assert that its network of prestressed struts and cables contribute to the structural integrity of the footbridge.

They define the tensegrity elements as follows:

•Masts: fabricated tubular steel sections up to 30m long with section sizes 610-905mm diameter
•Major mast cables: high-strength spiral wound galvanised wire ropes 30-80mm diameter
•Spars: circular hollow sections up to 23m long with section sizes 457-508mm diameter
•Spar cables: high-strength stainless steel spiral wound cables 19-32mm diameter

They then elaborate:

Pairs of major raking tubular steel masts spring from the main support piers on either side of the main span, setting the locations of an approximately coplanar array of minor secondary masts. The major and minor masts are offset from the perpendicular both longitudinally and transversely, thus both preventing cable/mast or cable/cable clashes and providing the signature “randomness” without significantly reducing structural efficiency. Secondary cables connected to flying struts, themselves pure tensegrity elements (supported only by cables), provide lateral restraint to the masts.

"Pure tensegrity elements?" If your criteria is "supported by cables." But that is not our definition of tensegrity--that is the criteria for a tension structure. But set that aside to read the true function of this cable/strut array:

The tensegrity array of flying struts and cables that hovers above and beside the deck fulfils three critical functions:
•It suspends the canopy, allowing it to float above the deck with no apparent means of support.
•It laterally restrains the tops of all the masts, preventing them from buckling sideways under the loads arising from the suspension of the deck plus lateral and seismic forces.
•It works in unison with all the masts and cables to resist twisting and lateral forces arising from patch loads on the deck (i.e. crowds), wind and earthquakes

The report also discloses additions to the struts to dampen oscillation.

External ring impact dampers were used. TMDs were considered, but the difficulty of tuning to each mast frequency made them impractical. The ring dampers were designed in close consultation with the architect for minimal impact on aesthetics and lighting, and ability to be maintained or replaced at a future date. Each has a steel annulus weighing between 100kg and 250kg (depending upon mast size and frequency), supported by three steel cables just over half-way up the mast, and able to move relative to it. Impacts between the mast and the ring dissipate the energy that any vortex shedding excitation puts into the masts, and are softened by visco-elastic pads that absorb energy and reduce sound.

Thanks, Oasys, for the details, a new application of tensegrity-like networks: to "resist twisting and lateral forces" of an otherwise straightforward, gravity-dependent structure.

Links:

Oasys Software Case Studies: http://www.oasys-software.com/solutions/case-studies.html
Discussion on the wiki: http://tensegrity.wikispaces.com/Kurilpa+Bridgehttp://tensegrity.wikispaces.com/Kurilpa+Bridge

Thanks to Katrina for letting me know about the award.

Searching For Tensegrity

2011-10-16T12:35:00.000-07:00

Interest in tensegrity is declining, at least if you look at Google's search records. See chart:

The decline tracks similar declines in all things relating directly to Bucky Fuller, including geodesic domes and synergetics. See charts:

The only trend in the other direction is buckyballs--the magnetic toy must be boosting the results somewhat.

Links: To generate your own charts, go to Google Insights for Search.

Podiatrists Debate Tensegrity

2010-11-10T02:26:00.000-08:00

Doctors of the foot, ankle and lower leg got into a tensegrity debate recently. They argued about bones, fascia, joints, and whether podiatry benefits from thinking in terms of tensegrity, as in Myers' Anatomy Trains method. Let's listen in and then comment.

Howard: Fascia is a fascinating subject, particularly in light of the concept of the body being a self supporting tensegrity system. Tensegrity structures require CONTINUOUS tension networks (fascia, muscle, tendons and ligaments) and DISCONTINUOUS compression components (osseous structures of the skeleton). When tension within the fascia is continually and uniformily applied through the entire network, the body is capable of being a self supportive structure. Many fascia experts assert that the fascia is a continuous structure from the head to the feet. Because of its continuous nature, tension can be applied over the entire system when the windlass winds, and it would appear beneficial for posture in two fashions; overall fascial tightening for improved postural support and that normal sagittal plane dorsiflexion is occurring at the 1st MTP joint allowing normal forward progression. It completely integrates with Grecovetsky’s spinal engine process, as the same tension-compression, support network is synergestic with an energy storage, energy return gait machine.

Robert: I'm probably being grossly simplistic here but If I took a cadaver, stood it up, and dorsiflexed the big toe, it will still probably fall over. Or, better example, if I shot someone full of muscle relaxant and asked them to stand, the fascia / tensegrity won't hold them upright. When we use Botox to chill out a hypertonic Triceps surae group in a CP patient, the muscle relaxes and allows greater dorsiflexion, the fascia has not changed length, but the function has.

Howard:

By the same logic, if you removed their fascia, and the muscles still functioned (quite the hypothetical).....they would fall over as well. Think of the materials used to make a kite. The plastic covering, balsa wood, etc won't be stable enough to fly until a piece of string is added bowing the balsa wood and adding tension plastic covering and the system as a whole. It then becomes stable enough to fly as long as the tension remains continuous. As muscles press against fascia, they promote tension. It is the combination which allows for support and balance.

Eric: The body is not a tensegrity structure because we do have continuous compression components. The leg bone is connected to the thigh bone....

Howard: The last time I looked, the thigh and leg are separated by a joint at the knee, as are the hip and thigh, and ankle and foot. And, these bones would be loose and unstable without the accompanying soft tissues arranged as a continuous tension network.

Kevin: The body can't be a tensegrity structure since a true tensegrity structure does not have compression forces between its structural elements. The last time I checked, the hip, knee, ankle, subtalar, midtarsal joint and first metatarsophalangeal joint all had compression forces between their osseous structural elements. As soon as there are compression forces within the joints of the body, then the body becomes a non-tensegrity structure.

Howard: When trying to apply engineering principles to a biologic structure, there is going to be some distortion of the purest of these (engineering) principles to fit what is actually (biologically) present. That neither makes the body nor the principle incorrect. There is clearly a combination of tension/compression occurring in the human structure, and to my way of understanding, tensegrity-esque seems to make the most sense. I fully realize that we are not an absolute anything, so it is easy to find fault and be critical of any of these explanations. However, that does not render any of these "wrong", just that we have yet to develop a single method to describe the body's structural integration. Being able to poke a hole in one aspect does not make tension/compression any less valuable in helping to understand how the body functions. Recognizing the roll of the fascia as a broad based tension band does add to the discussion in a meaningful way, and this was the purpose of my comments.

Kevin, I do appreciate your remarks about tension across joints negating the idea that the body could be a tensegrity structure. Many years ago, Steven Levin, an orthopedic surgeon introduced me to the tensegrity concept. He was intrigued by these principles when he realized that after a major knee trauma, once the ligaments of this joint were repaired, and then adequately tightened, the knee joint SEPARATED. He recognized that as tension was applied across the joint surface, the dynamics entirely changed. So, if one were to measure the tension across any joint, it must either be opened or somehow invaded....and this may change the ability to measure the tension influence across these surfaces. We certainly see this on x-ray...that spaces exist between joint surfaces in weight bearing attitudes. I am quite sure that there are other explanations for this phenomena....and I look forward to hearing them.

Kevin: I think the concept of tensegrity is important for the podiatrist and clinician to understand since I believe, as you do, that the mechanical interactions between tension and compression forces within the locomotor apparatus of the bipedal human is critical to allow normal gait function to occur. Is the body a "tensegrity structure" in the strict definition of "tensegrity"? No. By the strict definition of tensegrity, since there are compression forces between the osseous structural components at the joints of the body and there significant bending moments within these osseous structural components during weightbearing activities, the rules of tensegrity are violated within the structure of the human body.

However, your term "tensegrity-esque" may be a better one that shows that the body isn't exactly a tensegrity structure but still allows the clinician to understand how important the mechanical interactions between the compression-bearing elements and tension-bearing elements are within the body.

Certainly, we wouldn't have osteoarthritis (OA) developing in the knee joint as individuals age if compression forces didn't exist between the femur and tibia during weightbearing activities. However, without the tensile forces from the meniscal ligaments that restrain the medial and lateral meniscus in their proper positions within the knee joint during these weightbearing activities, knee joint OA would occur at a much earlier age in an individual.

Therefore, the human body does rely on a remarkable balance between compression forces and tensile forces in order to accomplish its daily weightbearing tasks both smoothly and efficiently with little damage to its structural components. Is this tensegrity at work? No. But certainly the principles of tensegrity can be used to better understand how these balancing of compression and tension forces may occur in a harmonious fashion within the human body.

Finis

The cast of characters:

Kevin A. Kirby, DPM, Adjunct Associate Professor, Department of Applied Biomechanics, California School of Podiatric Medicine at Samuel Merritt College
Howard Dananberg, J DPM, Bedford Podiatry Group, Eastman Ave, Bedford, NH
Eric Arthur Fuller, DPM, Berkeley and Oakland, CA
Robert Isaacs, BSc, MSChP, specialist in Paediatric Biomechanics (children's feet). Writes a column on biomechanics for "Podiatry Now", the journal for the Society of Chiropodists and Podiatrists.

Link: http://www.podiatry-arena.com/podiatry-forum/showthread.php?p=178063

Alexander Tensegrity

2010-11-09T02:00:00.000-08:00

Movement therapy practitioners such as Rolf, Pilates, and Alexander teachers, continue to publish about tensegrity. Its fascinating form and diversified deployment of tension and compression help these teachers communicate difficult concepts of balance and integrity to their patients.

Joining the long roster is Carol Boggs, an Alexander Technique teacher with B.S. and M.A. degrees in dance. Boggs, inspired by Levin, is developing Alexander teaching materials that use tensegrity to model support in the human body. She wrote, "the importance of fluid resiliency and supple tissue plasticity are key concepts that partner well with principles of tensegrity."

Below is reproduced verbatim her procedure to make a tensegrity model. I like how she starts with the paired sticks bound together, only to release them near the end.

Carol Boggs: How to Make A Tensegrity Model

The expanded octahedron (nearly icosahedron) offers an illustration of the three dimensions, height/vertical, width/horizontal, and depth/sagittal, expanded into a voluminous polyhedron. This model demonstrates the principle of struts suspended within tensile forces and an interior open spaciousness without a tightly held core. While the rubber band model is not ideal, i.e. the tensile forces do not get stiffer with increased loading, it is a good first step in moving away from the axial-loaded compression model to an understanding of a tensegrity model. Materials needed: six 3" rubber bands, six plastic straws cut slightly shorter than the rubber bands and shallowly notched on each end, six 5/8" rubber bands (commonly used for small braids), and pair of scissors.

With a small rubber band, loosely bind one end of the first pair of straws together, 1/3 in from end. This will be the vertical pair.
Bind the other 2 pairs of straws the same way.
Holding the first pair in a vertical profile orientation seeing only one of the 2 straws, insert the second pair horizontally between the members of the vertical pair to make a "+".
With a small rubber band bind the free end of the first pair to stabilize.

Insert the third pair, creating the third dimension, around the verticals of the first pair and between the horizontals of the second pair.
Bind the free ends of the second and third pairs.
Snug the 6 small rubber bands toward the center - You now have a symmetrical 3-D "+" sign.
Hold the 3-D sign so that you face the vertical pair in profile, notice that the sagittal (forward/back) pair is perpendicular to and straddles the vertical pair. Twist the vertical straw-facings so that you cannot see the notches. This makes them ready to accept the large rubber bands along the long axis of the straw. Do this for each pair.

Loop a large rubber band over one end of a straw, fitting it into the notch. Pass the other end of the rubber band between the adjacent perpendicular straws and fit it into the notch at the other end of the same straw. Do this for all 6 straws using one large rubber band per straw.
Stretch the mid-point of one side of the rubber band and fit it into the nearest perpendicular straw notch above it. Stretch the mid-point of the other side of the same rubber band and fit it into the other perpendicular straw notch. Do this for all six rubber bands (12 stretches).

Snip the 6 small rubber bands holding the 3-D plus sign together.

VOILA! You have a tensegrity structure.

Links:

http://www.carolboggs.com/howto.html

Spanish Woven Building Inspired by Tensegrity

2010-11-08T03:54:00.000-08:00

Readers of this blog and Snelson's work know that tensegrity can be usefully considered as a form of weaving. The Spanish pavilion at the Shanghai World's Fair, just closed, was a tour de force of woven and triangulated frameworks. While I see no pure tensegrity in this complex structure, in the sense of sharply divided tensile and compressive elements, the marketing materials make this tensegrity-oriented claim:

The free form of the structure is characterized by complex curvatures that made necessary the development of an independent structural system to support the form. The search for this structural expression is defined by a search for the "tensegrity" of the form, the double curvature wrapping facade that constituted, simultaneously, the solution to the problem and a challenge.

The building is clad in wicker and is translucent, in a deliberate evocation of Spanish basket weaving techniques. The wicker panels were woven by local wicker craftsmen of the Shandong region (Northeast China).

Each panel is made of woven wicker fibers that wrap around a slightly distorted metal frame to give the panel a warping effect. The different densities of wicker fibers let through to the interior of the pavilion changing light and shade.

In the center of the pavilion is a giant baby. Hmmmm. Do they claim the baby's diaper is a tensegrity as well? Why not--all cloth is tensile technology.

Links http://www.architypereview.com/ar_v4n4-spanish-pavilion.php

Tensegrity and Lightweighting

2010-11-02T21:25:00.000-07:00

In the material sciences, lightweighting means optimizing your design’s geometry and structure so that it uses less material. The aluminum Coca Cola can is an outstanding example of lightweighting. In the late 1970s the Aluminum Company Of America or ALCOA began offering lightweighting services to can manufacturers. They defined lightweighting as designing a can to use the thinnest aluminum that will still meet specs for strength and appearance. By using laboratory trial and error, and later computer algorithms such as finite element methods (FEM) and analysis, ALCOA's materials researchers reduced aluminum sheet thickness in soda cans from .015 inches to today's 0.115, a savings of millions of tons of aluminum annually.

Today such scientists are considering tensegrity as one of th

eir lightweighting tools. Autodesk, a leading provider of computer aided design (CAD) sells a product, Inventor, that can apply FEM and other stress analyses to virtual models. The result is good news for tensegrity: Autodesk produced a set of accessible, easy to understand videos about force, stress and ultimately, tensegrity. Some quotes from the video:

So far, we've seen how stress can be the enemy when trying to lightweight. Too much stress, too little materials and you've got problems. But not all stresses are created equal. Sometimes turning compressive stress into tensile stress can help you reduce material use enormously.

Buckminster Fuller called the strategy of using tension for structural integrity, "tensegrity. " It's great when using materials whose strength in tension is similar to its strength in compression.

Anything that is resisting compressive forces is resisting buckling. Compression can buckle your product long before the strength of the materials fail. The longer and skinnier your parts are, like spokes, the more likely they are to buckle, and the more you can lightweight them by using tension.

In the Needle Tower sculpture the rods and the cables are under the exact same amount of stress, but the much lighter cables are under tension, while the rods are in compression. The stress at which a column buckles is inversely related to the square of how slender the column is. So making a column 3x more slender makes it 9x more likely to buckle. By contrast a part under tension does not need to worry about this buckling equation. If it fails, it will fail at the yield strength of the material.

The video makers conflate tensegrity and tensile structures. They claim, for example, that old sailing ship masts and suspension bridges like the Golden Gate Bridge are examples of tensegrity. Even the claim that a bicycle wheel is a tensegrity is debatable, though it is refreshing to hear them discuss pneumatics as a form of tensegrity.

But Jeremy Faludi's detailed discussion of force distribution, and the wonderful animations by Mr. Animation, make their videos a welcome addition to any tensegrity video library. And I like their closing line:

When it comes to lightweighting, stress can be your friend.

Watch them here or follow the links below to the Autodesk site.

Introduction to Lightweighting and Material Reduction

Learn what lightweighting is, and why it’s important for sustainability; when you should lightweight; and other strategies you can use to reduce material use.

Lightweighting 1: Hollow Parts, Reinforcements, and Trusses

: How can you make your designs strong and light by optimizing geometry and structure? Strategies include hollow parts, ribs, posts, corrugation, trusses, and gussets.

Lightweighting 2: Lines of Force and Stress Concentrations

: The forces acting on your design can dictate its structure. Learn how you can use geometry like radiused corners to avoid failures from stress concentrations.

Lightweighting 3: Tensegrity Structures

: Learn how to use tension instead of compression to maintain structural integrity and reduce material use, and about tensegrity's application on designs from bike wheels to aluminum cans.

Links
View the videos here, or download them http://students.autodesk.com/?nd=sustainable_course&course_id=2.

Autodesk Education Community, http://students.autodesk.com/?nd=sustainable_strategy&course_id=2#introductiontolightweightingandmaterialreduction
ALCOA Beverage Can Story and Lightweighting, http://www.psc.edu/science/ALCOA/ALCOA.html

Tensegrity and Disease: Function Follows Form

2010-11-01T21:30:00.000-07:00

Over 100 years ago skyscraper builder Louis Sullivan famously wrote,

It is the pervading law of all things organic and inorganic,
Of all things physical and metaphysical,
Of all things human and all things super-human,
Of all true manifestations of the head,
Of the heart, of the soul,
That the life is recognizable in its expression,
That form ever follows function. This is the law.

Sullivan got it half right. Though it is often the case that form follows function, at the cellular level, function follows form. At least, that is the finding of cell morphology studies, the field that analyzes cellular form. Such reports show that cells rely on their shape for all kinds of information, and a bad shape can mean a bad disease.

A recent publication on this theme is, "Mechanotransduction and epigenetic control in autoimmune diseases" by Gonzáleza et al. This Chilean team focused on epithelial cells. The epithelium is your slimy, gooey self, as opposed to your webby "connective" self, strong "muscular" self and brainy "nervous" self. These four types --epithelial, connective, muscular and nervous tissue--are the four classifications that account for each of the 100 quadrillion cells that make up your body.

The epithelial cells ooze important enzymes and participate in your sense of touch--if they stop working, you are very sick. The Chilean doctors proved that the epithelial cells that ooze spit (saliva, in medical terminology) from people with Sjögren's syndrome display different patterns of cell adhesion and shape.

Ingber pioneered many aspects of this type of study, and was the first to focus on tensegrity. Without tensegrity, you are left with other structural ideas, such as the inflated balloon, or a pile of bricks. Balloons and bricks, when stressed locally, show local deflection. Push a balloon and it dimples; push a brick and it either coheres with the other bricks are shears and falls off. A tensegrity, on the other hand, shows a global reaction and response--areas far from the area of pressure may contract. Ingber documents this global nature of cell morphology, in for example, a tensegrity fabric. You can see the video here: http://wyss.harvard.edu/viewmedia/26/retracting-tensegrity-fabric-

Note that the material simultaneously retracts throughout its entire depth. When the ECM adhesions of a spread, adherent cell are dislodged using trypsin, the cell, cytoplasm and nucleus all simultaneously retract as the cell rounds. A prestressed tensegrity fabric created from 36 interconnected tensegrity modules of the type shown in Fig. 1B that experiences a distending force at the top right corner; the other three corners are fixed. Notice that the entire material responds to the local force and that it exhibits undulating motion.

According to this approach, disease is not caused by invading bacteria, badly transcribed genes, or bad genes transcribed accurately. Instead, our focus turns to the mechanics of the cell, its beams and girders, though of course in cellular mechanics you won't find such gross structures-researchers look instead at molecules that mediate mechano-transductions, including the extracellular matrix (ECM) molecules, transmembrane integrin receptors (more on them in a moment), the intracellular cytoskeleton (CSK) structures, and their role in tissue regulation.

Ingber invented nano-scale magnetic twisting devices to test his ideas. The tiny manipulators can pinch specific integrins on a cell's surface. Integrins are prodded, since they are the cell's ECM sensors. Their manipulation has been found to be critical for regulation of cell growth, differentiation, tissue pattern and more. The ECM, via integrin receptors and other mechanisms, regulates cell and tissue morphogenesis by altering the structure of the CSK which, in turn, serves to orient much of the cell's metabolic machinery. Ingber has slowly built a body of evidence-based research measuring effects on CSK mechanics that result from independently varying cell-ECM contacts, cell shape, applied mechanical stresses, and the area over which forces are applied.

Being in good shape is no longer just an American English cliche for being in good health: these studies show that it is literally shape that determines whether your cells are healthy or diseased. Think about that when you stretch or slouch, have good posture or poor: tensegrity research shows, function follows form.

Electro-Shock Tensegrity

2010-10-30T14:20:00.000-07:00

Polish massagists applied electric shock in an evidence-based study, and find the results prove the tensegrity model of the human body and its applicability to massage therapy models. They write in their abstract:

Based on a tensegrity principle, direct or indirect connections between fascia or muscles which stretch the aponeurosis or intermuscular septum may allow the transfer of tension over long distances, without loss of muscle force produced during rest and activity. The present study aimed to test an effect of massage on electrical (EMG) and mechanical (MMG) activities of a muscle lying distant, but indirectly connected to, the massaged muscle. Thirty-three healthy men participated in the study. To record the activity of the middle deltoid muscle the brachioradialis was massaged, and for the tensor fasciae latae-the peroneal muscles were massaged. An EMG/MMG hybrid probe was used to detect EMG and MMG signals from the middle deltoid and tensor fasciae latae muscles. The EMG amplitude increased during massage in the tensor fasciae lata only, while the MMG amplitude increased significantly in both muscles.

The study concludes that there was an electrical as well as a mechanical response of muscle connected indirectly by structural elements with the muscle being massaged indicating an application for the tensegrity principle in massage therapy. It also has a practical importance, because it provides a means for a physiotherapist to influence adverse muscle tension by massaging another distant muscle.

Links:

http://www.ncbi.nlm.nih.gov/pubmed/19329052

Reference:

Tensegrity principle in massage demonstrated by electro- and mechanomyography. By Kassolik K, Jaskólska A, Kisiel-Sajewicz K, Marusiak J, Kawczyński A, Jaskólski A. In Department of Physiotherapy, University School of Physical Education, Faculty of Physiotherapy, 51-612 Wrocław, al. Paderewskiego 35/p-4, Poland.

Ingber, Biotensegrity Pioneer, Builds NanoHeart

2010-10-29T12:00:00.000-07:00

A heart-lung micromachine will be built by Inbger, the father of cellular biotensegrity and the tensegrity model of cellular mechanics, has been awarded more than $3 million in funding from the National Institutes of Health and the U.S. Food and Drug Administration to develop a "Heart-Lung Micromachine" that will accelerate drug safety and efficacy testing. From the press release:

The Heart-Lung Micromachine will be based on novel Wyss Institute technology that combines microfabrication techniques from the computer industry with modern tissue engineering techniques, human cells, and a vacuum pump to replicate the complex physiological functions and mechanical microenvironment of a breathing lung and beating heart... The micromachine will build on recent groundbreaking work by Ingber and Parker in developing the technology for building tiny, complex, three-dimensional models of human organs. These "organs on chips" mimic the complicated mechanical, cellular, and biochemical functions of specific organs, such as the lung. The proposed heart-lung device will mark a new milestone by combining two different organ systems within a single microsystem for the first time.

Ingber is working on other organ models as well, such as a kidney-on-a-chip that produces urine and an intestine-on-a-chip that exhibits peristalsis. An artificial spleen-on-a-chip is also being developed, as well as a sepsis therapeutic device, a blood infection diagnostic, and even bone marrow and cancer models. Shown here is the "lung on a chip," photo by Felice Frankel.

Okay, no tensegrity is in the announcement, but I mention it because nanotech and tensegrity are hooking up more and more often, and anyway, Ingber is a tensegrity hero! We salute him in all his efforts.

Video:

Links

Announcement: http://wyss.harvard.edu/viewpressrelease/42

Photo of lung on a chip: http://wyss.harvard.edu/viewmedia/145/lung-on-a-chip;jsessionid=C34A0102D3B1A7AD70EF49593C5726A2.wyss1

Tensegrity from DNA Origami

2010-10-28T03:08:00.000-07:00

Fold your own DNA in a DNA Origami online simulator made available by Wyss Institute researchers. They released the recent tiny DNA tensegrity that we reported on here. They named this construction work "DNA Origami," a technique for folding pieces of DNA into shapes.

With DNA origami, researchers take a long, single strand of DNA (called a scaffold) and fold it into a structure of their own design. These designs are held together with short "staple" strands, which are also made of DNA. Quote:

Each staple is coded with two specific sequences: one is the complement to a specific site on the scaffold; the other is the complement to a second location on the same scaffold. When the scaffold and staples are allowed to "self-assemble," the attachment of the staple strands causes the scaffold to bend and fold into the desired structure. In principle, the same approach could be used with RNA or any other informational molecule where complementary sequences can be engineered. The Wyss scientists can form three-dimensional shapes, such as a 3 strut t-prism, icosahedron, and other twisted and curved shapes. Their long-term goal is to produce cages, such as viruses do, in order to deliver desired pharmaceutical cargo to cells.

These scientists have now made available online a simulator of their work. The interactive feature that illustrates the basic idea of DNA origami by letting you manipulate a biomolecule, such as DNA or RNA. The general idea is the same as DNA origami, but instead of adding staple strands to the scaffold, you define the binding sequences on scaffold, keeping in mind how you'd like the strand to fold. They write,

When you're satisfied with your coding, click on the "Self-Assemble" button and watch the strand fold up on itself, connecting at points you've selected. The molecule should take shape as planned -- or not! Either way, you might discover something interesting as you build.

Links:

http://wyss.harvard.edu/viewpage/m-o/interactive-feature-molecular-origami

Tensegrity Bibliography from Gómez Jáuregui

2010-10-27T08:01:00.001-07:00

Valen first gave us a comprehensive dissertation on structural tensegrity, contributing a wonderfully level-headed update of tensegrity's tangled history. His dissertation is now published and for sale as a book.

Now Valen continues to help the tensegrity community. He shares his Excel bibliography listing 300 articles on tensegrity. The link is below. The Excel format is ideal for easy search and sorting.

So much to read, so little time. Just for fun, I used Excel to run a quick linguistic analysis of the list. Here are the most frequent occurring words, and their word count:

010 Optimization
011 Mechanical
012 Cells
012 Form-finding
013 Mechanism
014 Active
018 Dynamic
018 Planar
018 Static
025 Design
026 Systems
031 Analysis
038 Control
124 Structures
200 Tensegrity

A lot of these articles are uploaded on scribd, take a look: http://www.scribd.com/tensegritywiki. Below, I paste his 300 titles, in alphabetical order, just to drool over this cornucopia of tensegrity academia:

A Direct Approach To Design Of Geometry And Forces Of Tensegrity Systems
A Discussion On Control Of Tensegrity Systems
A Force And Torque Tensegrity Sensor
A Marching Procedure For Form-finding For Tensegrity Structures
A Method To Generate Stable, Collision Free Configurations For Tensegrity Based Robots
A Monte Carlo Form-finding Method For Large Scale Regular And Irregular Tensegrity Structures
A New Tensegrity Module - "Torus"
A New Topology Of Tensegrity Towers With Uniform Force Distribution
A Polyhedron Made Of Trnas
A Semidefinite Programming Approach To Tensegrity Theory And Realizability Of Graphs
A Simplified Strategy For Force Finding Analysis Of Suspendomes
A Study Of Two Stochastic Search Methods For Structural Control
A Sub-cellular Viscoelastic Model For Cell Population Mechanics
A Tensegrity Structure With Buckling Compression Elements: Application To Cell Mechanics
A Visualization Method For The Morphological Exploration Of Tensegrity Structures
A Wrench-sensitive Touch Pad Based On A Parallel Structure
Abnormal Fiber End Migration In Royal College Of Surgeons Rats During Posterior Subcapsular Cataract Formation
Accurate Simulation Of Near-wall Turbulence Over A Compliant Tensegrity Fabric
Active Control Of A Tensegrity Plane Grid
Active Control Of Tensegrity Structures Under Random Excitation
Active Control Of Tensegrity Systems
Active Tensegrity Structure
Active Tensegrity: A Control Framework For An Adaptive Civil-engineering Structure
Active Vibration Control Of A Three-stage Tensegrity Structure
Adaptive Force Density Method For Form-finding Problem Of Tensegrity Structures
Adjustable Tensegrity Structures
Advanced Form-finding For Cable-strut Structures
Advanced Form-finding Of Tensegrity Structures
Algebraic Tensegrity Form-finding
An Active Structure That Adapts And Learns
An Active, Structure That Learns
An Introduction To The Mechanics Of Tensegrity Structures
Analysis Of The Properties Of Integrally Tensioned Tensegrity Domes
Application Of Biomechanics To Tissue Engineering: A Personal View
Applications Of Combinatorics To Statics - A 2nd Survey
Architectural Element For Covering Infrastructure E.G. Element Of Roof, Has Grid Having Strips So That Height Of Strip Is Less Than Half Of Width To Fasten Strips To Membrane Supported By Grid
Assembly Holder For Constructing Tensegrity Structure Before/During Attachment Of Steel Cable Components To Pressure Rods Comprises Geometric Axis That Forms At Each End Of The Holder The Normal Of The Axis Of Pressure Element
Automated Discovery And Optimization Of Large Irregular Tensegrity Structures
Backlash-free Motion Control Of Robotic Manipulators Driven By Tensegrity Motor Networks
Base Module For Spatial Structure Comprises Six Rigid Bars With Tips Linked By Pre-tensioned Cables To Form Polyhedron With Triangular Faces
Biological Design Principles That Guide Self-organization, Emergence, And Hierarchical Assembly: From Complexity To Tensegrity
Building Tension In Buffalo
Cable-strut Systems: Part I - Tensegrity
Cable-strut Systems: Part Ii - Cable-strut
Cellular Tensegrity And Mechanochemical Transduction
Change Of The Topography Of Ventral, Cell Surface During Spreading Of Fibroblasts As Revealed By Evanescent Wave-excited Fluorescence Microscopy: Effect Of Contractility And Microtubule Integrity
Changing Morphology In Tubular Structures
Closed-form Equilibrium Analysis Of A Planar Tensegrity Structure
Closed-form Equilibrium Analysis Of Planar Tensegrity Structures
Combining Dynamic Relaxation Method With Artificial Neural Networks To Enhance Simulation Of Tensegrity Structures
Comparison Between Experimental Tests And Numerical Simulations Carried Out On A Tensegrity Minigrid
Composite Hydrophone Devices Coupling Piezoelectricity And Tensegrity
Composite Profiles And Membranes Tensegrity Panels
Conditional Ellipticity And Constrained Optimization
Configurations Of Few Lines In 3-space - Isotopy, Chirality And Planar Layouts
Constraining Plane Configurations In Cad: Circles, Lines, And Angles In The Plane
Constructing Tensegrity Structures From One-bar Elementary Cells
Control And Simulation Of A Tensegrity-based Mobile Robot
Control Of A Seismically Excited Benchmark Building Using Linear Matrix Inequality-based Semiactive Nonlinear Fuzzy Control
Control Synthesis For A Class Of Light And Agile Robotic Tensegrity Structures
Control/Structure Optimization Approach For Minimum-time Reconfiguration Of Tensegrity Systems
Controlling Instability With Delayed Antagonistic Stochastic Dynamics
Cpg Control Of A Tensegrity Morphing Structure For Biomimetic Applications
Crawling By Body Deformation Of Tensegrity Structure Robots
Damage Assessment Of Tensegrity Structures Using Piezo Transducers
Decentralized Control Of Stable-element Tensegrity Plates
Dense Filling Type Tensegrity Joint For Tensegrity Structure, Has Coated Tension Portions, Each Converge Into Guidance Slit Facing Across Cylindrical Tunnel
Deployable Plates Made From Stable-element Class 1 Tensegrity
Deployable Structures In Nature: Potential For Biomimicking
Deployable Tensegrity Reflectors For Small Satellites
Deployment Of A Class 2 Tensegrity Boom
Deployment Of Tensegrity Structures
Design And Control Of Tensegrity Robots For Locomotion
Design For Shape Control Of Tensegrities
Design Methods Of Rhombic Tensegrity Structures
Design Of Tensegrity Structures Using Parametric Analysis And Stochastic Search
Design, Modeling, And Optimization Of Compliant Tensegrity Fabrics For The Reduction Of Turbulent Skin Friction
Designing Structures For Dynamical Properties Via Natural Frequencies Separation Application To Tensegrity Structures Design
Designing Tensegrity Modules For Pedestrian Bridges
Designing Tensegrity Systems: The Case Of A Double Layer Grid
Determination Of The Analytical Workspace Boundaries Of A Novel 2-dof Planar Tensegrity Mechanism
Developing Intelligent Tensegrity Structures With Stochastic Search
Developments In Tensegrity Systems - An Overview
Dihedral 'star' Tensegrity Structures
Direct Measurement Of The Force Generated By A Single Macrophage
Direct Mechanical Measurement Of Geodesic Structures In Rat Mesenchymal Stem Cells
Dna-based Nanostructures: Changes Of Mechanical Properties Of Dna Upon Ligand Binding
Domain Decomposition Approach For Non-smooth Discrete Problems, Example Of A Ten-segrity Structure
Double-layer Grids: Review Of Dynamic Analysis Methods And Special Topics
Double-layer Tensegrity Grids - Static Load Response .1. Analytical Study
Double-layer Tensegrity Grids - Static Load Response .2. Experimental-study
Dynamic Behavior And Vibration Control Of A Tensegrity Structure
Dynamic Behavior Of A Tensegrity System Subjected To Follower Wind Loading
Dynamic Equations Of Motion For A 3-bar Tensegrity Based Mobile Robot
Dynamic Simulation Of A Spatial 3-dof Tensegrity Mechanism
Dynamic Workspace And Control Of Planar Active Tensegritylike Structures
Dynamic Workspace And Control Of Planar Active Tensegrity-like Structures
Dynamics And Control Of Tensegrity Systems
Dynamics Of Systems With Rods
Dynamics Of Tensegrity Systems: Compact Forms
Dynamics Of The Shell Class Of Tensegrity Structures
Economic Sensor/Actuator Selection And Its Application To Flexible Structure Control
Effect Of Mechanic Vibrating Non Ioniation Stimulation
Equilibria And Stiffness Of Planar Tensegrity Structures
Equilibrium Conditions Of A Class I Tensegrity Structure
Equilibrium Conditions Of A Tensegrity Structure
Evolutionary Development Of Tensegrity Structures
Evolutionary Form-finding Of Tensegrity Structures
Exploring Cellular Tensegrity: Physical Modeling And Computational Simulation
Finite Element Based Form-finding Algorithm For Tensegrity Structures
Finite Element Simulation Of Mechanical Tests Of Individual Cells
First-order Infinitesimal Mechanisms
Folding Tensegrity Systems - Six Strut Modules And Their Assemblies
Force Propagation And Force Generation In Cells
Form Finding Analysis Of Tensgrity Structures Based On Variational Method
Formation Shape And Orientation Control Using Projected Collinear Tensegrity Structures
Form-finding Of Complex Tensegrity Structures: Application To Cell Cytoskeleton Modelling
Form-finding Of Nonregular Tensegrities Using A Genetic Algorithm
Form-finding Of Nonregular Tensegrity Systems
From Active To Intelligent Structures
From Graphs To Tensegrity Structures: Geometric And Symbolic Approaches
Fuller,Buckminster Tensegrity Structures And Maxwell,Clerk Rules For Construction Of Stiff Frames
Gait Production In A Tensegrity Based Robot
General Class Of Tensegrity Structures: Topology And Prestress Equilibrium Analysis
Geometric Effects In An Elastic Tensegrity Structure
Geometrical Non-linear Analysis Of Tensegrity Systems
Geometrically Nonlinear Static Behavior Of Cable Structures
Geometry Of Configuration Spaces Of Tensegrities
Growing Form-filling Tensegrity Structures Using Map L-systems
High Magnetic Gradient Environment Causes Alterations Of Cytoskeleton And Cytoskeleton-associated Genes In Human Osteoblasts Cultured In Vitro
How An Eukaryotic Cell Senses The Substrate Stiffness? An Exploration Using A Finite Element Model With Cytoskeleton Modelled As Tensegrity Structure
Hypar Tensegrity Dome Construction Methodology
Immunohistochemical Aspects Of The Fibrogenic Pathway In Nephrogenic Systemic Fibrosis
Implicit Mechanistic Role Of The Collagen, Smooth Muscle, And Elastic Tissue Components In Strengthening The Air And Blood Capillaries Of The Avian Lung
Improvement Of Force Modulation Mode With Scanning Probe Microscopy For Imaging Viscoelasticity Of Living Cells
Inducing Reversible Stiffness Changes In Dna-crosslinked Gels
Inelastic Mechanics Of Sticky Biopolymer Networks
Infinitesimal Mechanism Modes Of Tensegrity Modules
Influence Of Laminar Shear Stress On Cytoskeleton And Icam-1 Expression Of Endothelial Cells
Initial Self-stress Design Of Tensegrity Grid Structures
Initial Shape Finding And Modal Analyses Of Cyclic Right-cylindrical Tensegrity Modules
Initial Shape-finding And Modal Analyses Of Cyclic Frustum Tensegrity Modules
Innovative Deployable Antenna Developments Using Tensegrity Design
Input/Output Selection For Planar Tensegrity Models
Input-output Selection For Planar Tensegrity Models
Integrated Control/Structure Design For Planar Tensegrity Models
Integrated Structure And Control Design Of Modular Tensegrities
Intermediate Filament-deficient Cells Are Mechanically Softer At Large Deformation: A Multi-scale Simulation Study
Investigation Of Clustered Actuation In Tensegrity Structures
Joint For Use In Foldable Tensegrity Structure, Has Joint Main Body For Connecting Tiltable Rods, In Which Tilting Center Of Each Rod Is Positioned On Circular Track And Connection Rod Is Arranged At Central Point Of Circular Track
Kinematic Analysis Of A Planar Tensegrity Mechanism With Pre-stressed Springs
Kinematic And Dynamic Analysis Of A Spatial One-dof Foldable Tensegrity Mechanism
Kinematic And Static Analysis Of A 3-pu(P)Under-bars Spatial Tensegrity Mechanism
Kinematic And Static Analysis Of A Planar Modular 2-dof Tensegrity Mechanism
Kinematic And Static Analysis Of A Three-degree-of-freedom Spatial Modular Tensegrity Mechanism
Kinematic, Static And Dynamic Analysis Of A Planar 2-dof Tensegrity Mechanism
Kinematic, Static, And Dynamic Analysis Of A Planar One-degree-of-freedom Tensegrity Mechanism
Kinematic, Static, And Dynamic Analysis Of A Spatial Three-degree-of-freedom Tensegrity Mechanism
Kinematics, Dynamics And Control Of A Planar 3-dof Tensegrity Robot Manipulator
Learning, Self-diagnosis And Multi-objective Control Of An Active Tensegrity Structure
Limit Analysis And Failure Of Load-carrying Systems
Linear Dynamics Of Tensegrity Structures
Logarithmic Strain Measure Applied To The Nonlinear Positional Formulation For Space Truss Analysis
Mass Optimized Self-actuated Panels For Several Truss Core Topologies
Mathematics And Tensegrity
Mechanical Behavior Of A Tensegrity Dome
Mechanical Response Of A Tensegrity Structure Close To Its Integrity Limit Submitted To External Constraints
Mechanisms Of Prestressed Reticulate Systems With Unilateral Stiffened Components
Method Of Converting Tensegrity Structure Into Musical Instrument, Involves Tying Struts Together At Internal Strut Nodal Minimum Of Desired Resonate Modes Of Struts
Minimum Mass Design Of Tensegrity Towers And Plates
Model Of Mechanical Interaction Of Mesenchyme And Epithelium In Living Tissues
Modelling And Control Of Class Nsp Tensegrity Structures
Modelling Organ Deformation Using Mass-springs And Tensional Integrity
Models Of Complex Systems Behaviour
Modern Stadia History And The Use Of Concrete
Modular Polyhedral Building Elements|comprises Compression And Tension Elements Defining Polyhedron And Interconnecting Other Modules
Molecular Geometry From Molecular Tensegrity: A Case Study Of Gas-phase Mx2 Compounds
Molecular Tensegrity: Predicting 1,3-x---x Distance In Gas-phase Mxn (N <= 4) Compounds From Atomic Sizes
Morpho: A Self-deformable Modular Robot Inspired By Cellular Structure
Movement Control Of Tensegrity Robot
Multiobjective Optimization For Force Design Of Tensegrity Structures
Nonequilibrium Statistical Mechanical Models For Cytoskeletal Assembly: Towards Understanding Tensegrity In Cells
Nonlinear Analysis And Optimum Design Of Cable Domes
Non-linear Displacement Control Of Prestressed Cable Structures
Nonlinear Elastoplastic Analysis Of Tensegrity Systems
Non-linear Static Analysis And Design Of Tensegrity Domes
Non-symmetrical Tension-integrity Structure
Numerical Form-finding Of Tensegrity Structures
On Characterizations Of Rigid Graphs In The Plane Using Spanning Trees On Characterizations Of Rigid Graphs In The Plane
On Mechanical Modeling Of Dynamic Changes In The Structure And Properties Of Adherent Cells
On The Elastica Solution Of A T3 Tensegrity Structure
On The Elastica Solution Of A Tensegrity Structure: Application To Cell Mechanics
On The Singularities Of A Constrained (Incompressible-like) Tensegrity-cytoskeleton Model Under Equitriaxial Loading
On The Singularities Of Constrained Tensegrity Systems - Application To A Modified T3 Model
One-story Buildings As Tensegrity Frameworks .3.
Open-loop Control Of Class-2 Tensegrity Towers
Optimal Complexity Of Deployable Compressive Structures
Optimal Tensegrity Structures In Bending: The Discrete Michell Truss
Optimization Of A Tensegrity Wing For Biomimetic Applications
Optimization Of Class-2 Tensegrity Towers
Optimization Of Tensegrity Structures
Optimum Shapes Of A Cable Dome Structure
Path Planning And Open-loop Shape Control Of Modular Tensegrity Structures
Path Planning For The Deployment Of Tensegrity Structures
Percolation Of The Loss Of Tension In An Infinite Triangular Lattice
Piezotensegritic Structures For Transducer Applications
Projective Background Of The Infinitesimal Rigidity Of Frameworks
Proportional Damping Approximation Using The Energy Gain And Simultaneous Perturbation Stochastic Approximation
Quasi-tensegric Systems And Its Applications
Readily Erectable Building Structures|includes Roof Structure Incorporating Stressed Cables And Compressed Struts With Structure Supported By Lugs
Realizability Of Graphs In Three Dimensions
Real-time Self-collision Detection Algorithms For Tensegrity Systems
Redundancy In The Control Of Robots With Highly Coupled Mechanical Structures
Redundant And Force-differentiated Systems In Engineering And Nature
Regenerative Tensegrity Structures For Energy Harvesting Applications
Reinforcement Learning For Structural Control
Reversible Switching Of Hydrogel-actuated Nanostructures Into Complex Micropatterns
Rigid Tensegrity Labelings Of Graphs
Rigidity And Polarity .2. Weaving Lines And Tensegrity Frameworks
Rigidity Of Packings
Role Of Cellular Tone And Microenvironmental Conditions On Cytoskeleton Stiffness Assessed By Tensegrity Model
Second-order Rigidity And Prestress Stability For Tensegrity Frameworks
Selection Of Prestress For Optimal Dynamic/Control Performance Of Tensegrity Structures
Self-assembly Of Three-dimensional Prestressed Tensegrity Structures From Dna
Self-aware And Learning Structure
Self-diagnosis And Self-repair Of An Active Tensegrity Structure
Self-stress Design Of Tensegrity Grid Structures With Exostresses
Sensor/Actuator Selection For The Tensegrity Structure
Shape Change Of Tensegrity Structures: Design And Control
Shape Control Of A Multi-agent System Using Tensegrity Structures
Shape Memory Effect In Tensegrity Structures
Shape Of Tensegrity Frames With An Optimum Rigidity
Simultaneous Structure And Control Optimization Of Tensegrities
Special Structures: Past, Present, And Future
Specific Mechanical And Structural Responses Of Cortical And Cytosolic Cytoskeleton In Living Adherent Cells
Spherical Dodecahedral Enclosure Used As E.G. Building, Pressure Vessel, Vacuum Vessel, Liquid Or Gas Container, Has Twenty Band Intersections Covered And/Or Sealed To Form Airtight Seal, And Seams Sealed To Make The Enclosure Airtight
Spiral Helix Tensegrity Dome|has All Junction Points Precisely Located From Jig For Construction With Top Closure
Square Grids With Long "Diagonals"
Stability Conditions For Tensegrity Structures
Stability Of A Tensegrity Structure: Application To Cell Mechanics
Stability Of An Elastic Cytoskeletal Tensegrity Model
Stability Of An Elastic Tensegrity Structure
Static Analysis Of Tensegrity Structures
Static And Dynamic Analyses Of Tensegrity Structures. Part 1. Nonlinear Equations Of Motion
Static And Dynamic Analyses Of Tensegrity Structures. Part Ii. Quasi-static Analysis
Static And Dynamic Characterization Of Regular Truncated Icosahedral And Dodecahedral Tensegrity Modules
Static And Dynamic Characterization Of Some Tensegrity Modules
Static Balancing Of Tensegrity Mechanisms
Static Balancing Of Tensegrity Mechanisms
Stiffness Analysis Of A 2-dof Planar Tensegrity Mechanism
Stiffness Of Planar Tensegrity Truss Topologies
Straightening Polygonal Arcs And Convexifying Polygonal Cycles
Straightening Polygonal Arcs And Convexifying Polygonal Cycles
Stress-dependent Morphogenesis: Continuum Mechanics And Truss Systems
Structural Approach Of Cytoskeletal Mechanics: Cellular Solid Vs Tensegrity Model
Structural Behavior And Design Methods Of Tensegrity Domes
Structures In Hyperbolic Space
Study The Effect Of Anticancer Drugs On Human Breast Cancer Cells Using Three Dimensional Silicon Microstructures
Symbolic Stiffness Optimization Of Planar Tensegrity Structures
Symmetric Prismatic Tensegrity Structures: Part I. Configuration And Stability
Symmetrical Reconfiguration Of Tensegrity Structures
Tensegrity Active Control: Multiobjective Approach
Tensegrity As A Structural Framework In Life Sciences And Bioengineering
Tensegrity Concept - From Natural Systems To Robots
Tensegrity Flight Simulator
Tensegrity Frameworks
Tensegrity Frameworks In One-dimensional Space
Tensegrity Frameworks: Dynamic Analysis Review And Open Problems
Tensegrity Frameworks: Static Analysis Review
Tensegrity Motion Control Using Internal Mechanisms
Tensegrity Spline Beam And Grid Shell Structures
Tensegrity Structure|has Tensegrity Module Including Several Compression Materials That Surround Tension Materials And Meander Along Stretch Direction Of Tension Materials
Tensegrity Structures In The Design Of Flexible Structures For Offshore Aquaculture
Tensegrity Structures Research Evolution
Tensegrity Structures With Buckling Members Explain Nonlinear Stiffening And Reversible Softening Of Actin Networks
Tensegrity Systems
Tensegrity: 60 Years Of Art, Science, And Engineering
Tension - Frequency Relation In Tensegrity System
Tensioned Fabric Membrane Roofs For ''tensegrity'' Domes
The Analysis Of Tensegrity Structures For The Design Of A Morphing Wing
The Analysis Of Tensegrity Structures For The Design Of A Morphing Wing
The Analysis Of Tensegrity Structures For The Design Of A Morphing Wing
The Cytoskeletal Organization Of Breast Carcinoma And Fibroblast Cells Inside Three Dimensional (3-d) Isotropic Silicon Microstructures
The Prestressability Problem Of Tensegrity Structures: Some Analytical Solutions
The Reverse Displacement Analysis Of A Tensegrity Based Parallel Mechanism
The Simple Model Of Cell Prestress Maintained By Cell Incompressibility
The Stiffness Of Prestressed Frameworks: A Unifying Approach
Threads For Holding Rods In Tensegrity Construction|has Threads Located In Slotted Ends Of Rods With Retaining Knots
Time-energy Optimal Control Of Hyper-actuated Mechanical Systems With Geometric Path Constraints
Topology Design Of Tensegrity Structures Via Mixed Integer Programming
Triangular Shape Module For Tensegrity Structure Construction|has Wire Rod Which Couples Central Poles Of Upper And Lower Surface
Two General Methods For Creating Tensegrity Structures Of Towers, Arches, Bridges And Stadium Roofs
Unstable-unit Tensegrity Plate: Modeling And Design
Using Of Tensegrity Grid Deformation To Identify Its Selfstress Level
Variable Antagonistic Stiffness Element Using Tensegrity Structure
Vibration And Damping In Three-bar Tensegrity Structure
Vibration Of An Elastic Tensegrity Structure
Zero Stiffness Tensegrity Structures

Links:

Download the file on Gómez Jáuregui's site, http://www.tensegridad.es/publications.html

Skwish Inspires Headphone Design

2010-10-27T07:19:00.000-07:00

Tom Flemons, who designed and packaged the Skwish, deserves the Nobel prize of tensegrity toymaking, as he put a tensegrity in the hands of millions of people and inspired all kinds of innovation.

Tom should be proud to know that the toy continues to introduce people to tensegrity and its inherently natural, 60 degree coordination of tensive and compressive force.

The skwish showed up this week in the blog of Teague designer Dana Krieger, as she announced her tensegrity-based concept headphones. A tension network of elastic bands enables these ear phone cups to fit more snugly and smoothly to any pair of ears, or so she claims. Krieger wrote,

Conventional headphones use a series of pivots and slides to locate the ear relative to the head. Executed in plastic and metal, these pivots squeak and rattle as they struggle to accommodate listeners. In contrast to this noisy intrusion, 20/20 leverages the unique properties of tensegrity to offer silent, organic motion.

Not too much detail in this video:

As usual with claims of tensegrity efficiency, we will need to take a close look at the degrees of freedom in the headphones as opposed to any older pair. But still, it is nice to see a tension net as attractive as this.

Next--matching tensegrity earrings, anyone?

Links:

Flemons latest work: http://www.intensiondesigns.com/

Teague blog: http://www.teague.com/blog/

Video: TEAGUE 20/20 Concept from TEAGUE

Core77 blogged it first: http://www.core77.com/blog/object_culture/teagues_buckminster_headphones_concept_17704.asp

Tensegrity Masts and a Cloud in London

2010-10-18T11:56:00.000-07:00

120 meter tall masts are planned to rise over London in honor of the 2012 Olympics. Tomas Saraceno, an artist inspired by Buckminster Fuller, is a main influence. He is working with Carlo Ratti and ARUP engineers that raised the recent Kurilpa bridge.

Like the bridge, these towers look more like tensile structures, or cable-stayed masts, than true tensegrities. But the design is breath-takingly bold and certainly deploys cutting edge tensile technology. From the treehugger report:

Designed by Carlo Ratti, head of the MIT SENSEable Cities Laboratory, it is "is a new kind of architectural landmark that will be built through grassroots fundraising and social networking efforts."

From the press release, we learn that other members of the design team include artist Tomas Saraceno, digital designer Alex Haw, lightweight-structures expert Joerg Schleich, engineering group Arup, landscape architects Agence Ter and the Internet company Google. Those advising the team include writer Umberto Eco and and MIT professor and artist Antoni Muntadas.

"Our main idea is to apply to architecture some of the distributed processes that are currently revolutionizing the digital world," says Professor Ratti. "For instance, we would like the Cloud to become a symbol of global ownership built through a bottom up fundraising effort."

The Cloud will also be "a vast, collective energy-harvesting effort," explains Alex Haw. People can choose to ascend the Cloud on foot or bicycle; the energy that it would take to descend the Cloud is converted, on the way down, into electricity through elevators with regenerative breaking, similar to those that are present in hybrid cars.

"The people's energy, coupled with solar energy collected through on-site and off-site photovoltaic cells and various energy saving strategies will allow us to reach carbon neutrality, whereby the Cloud produces all the energy it uses."

It is made with a giant tensegrity mast in the middle, with a double helical ramp for cyclists and pedestrians to take a very long ride. it looks like an engineering challenge, to put it mildly; however Joerg Schlaich is confident.

Having worked on lightweight structures for many decades, we can easily build this great CLOUD, on budget and on time for 2012!
Many tall towers have preceded this, but our great achievement is the high degree of transparency, the minimal use of material and the vast volume created by the spheres- all on exceedingly slender columns.

The spheres are inflatatable;

Each inflatable has its own air pump that controls air pressure level. All pumps are networked, thus forming a distributed, self-regulating system. Each pump will generate energy by letting air in and out during the daily heating and cooling cycles due to solar radiation. Inflatables on the periphery of the cloud are insulated with nanogel and kept hotter through internal resistors - so that they can float freely in air.

The remaining energy for the Cloud will be produced by thin film photovoltaics printed on inflatable membranes, doubling as solar shading in the summer in order to preserve maximum internal thermal comfort inside. It is expected that this will collect 200 MWh per year, making the Cloud not only zero emission but effectively 'below-zero emission' (the Cloud will be a net producer of energy to the East London community).

Professor Ratti is quoted in the press release:

"Our main idea is to apply to architecture some of the distributed processes that are currently revolutionizing the digital world," says Professor Ratti. "For instance, we would like the Cloud to become a symbol of global ownership built through a bottom up fundraising effort."
The size of the Cloud will not be set in advance, but it will evolve based on the level of contributions received. The global "cloudraising" effort will be supported by platforms such as Facebook and Twitter; Google will provide advertising on YouTube and in search results.

Video:

Links:

Raise the Cloud, the official website, http://www.raisethecloud.org

Carlo Riatti Associati site, http://www.carloratti.com/projects/026.htm

Treehugger report, http://www.treehugger.com/files/2009/12/cloud-tower-to-float-over-london.php

Biotensegrity in Rome

2010-10-14T13:05:00.000-07:00

Levin and Schleip are featured in Leonid Blyum's detailed report on a recent Biotensegrity meeting in Rome. His report is here, http://blyum.typepad.com/on_abr_and_beyond/2010/10/biotensegrity-meeting-in-rome.html, below are highlights:

I spent the last 5 days in Rome participating in the invitation-only event called 2^nd annual Bio-Tensegrity Group Meeting, which is a mastermind group with participants of diverse backgrounds – researchers; biomechanics scholars; bodywork practitioners – who contribute to the ongoing development of Bio-Tensegrity paradigm and study various avenues applying it in practice.

[Steve Levin] is 78 but until today maintains a remarkable energy and sharpness of mind. Usually I am rather stingy with the compliments but in his case I can only say that I wish I am able to retain such an intellectual shape when I am 78 myself :-)

Among other notables was Dr. Robert Schleip – universally regarded as the leader and one of the main driving forces behind the entire Fascia movement that became such a groundswell in the last few years. He was a key person behind 1^st and 2^nd Fascia Congresses; Fascia Research week in Ulm, Germany that I went to in March and tons of other events. Robert is quite an amazing person who manages to be equally comfortable and insightful everywhere – from a research lab to dealing with New Age ‘healers’. He is probably one of the most genuinely likeable personalities that I’ve ever come across in my life – he radiates most sincere interest to whatever the others are doing and embraces the new ideas without a hint of a prejudice. His newly found fame and importance did not get into his head at all – he is one of those rare people who manage to warm up the room and ease tensions everywhere he goes.
Dr. Danielle-Claude Martin... holds a Ph.D. in physics while being a martial arts expert at the same time. Danielle is the engine behind the BioTensegrity group who brings everyone and everyone together. A big boost of interest in BioTensegrity developed in the last 2-3 years once she has managed to design the experiential classes for teaching how to assemble biotensegrity models.

That turned out amazingly powerful – the transition from half a page-long formulas that were difficult to connect with reality to hands-on assembly of tensegrity models made understanding far more accessible and at the same time far more advanced and connectable to the modeling of musculoskeletal deformities. Regulating the stiffness, tension, attachments of the tensile elements has an amazing influence on the stability and behavior of the entire structure.

The picture above shows my early flawed attempts – an unstable and twisted construction (resembling the appearance of deformities in a quadriplegic child). The picture below – is a far better product that I eventually managed to deliver.

Of course, more advanced people are able to produce a lot more complicated models

...My presentation was titled “Using BioTensegrity framework in interpretation of multiarticular distortions in Cerebral Palsy” and I’d dare to say it was quite an eye-opener for the audience.

Links:

Levin's site, www.biotensegrity.com

ABR Blog by Leonid, http://blyum.typepad.com/

Tensegrity Systems by Skelton

2010-10-14T04:42:00.000-07:00

Read or download this excellent review of tensegrity from the perspective of static and dynamic analysis. This is the first book on tensegrity structures written to attempt to integrate structure and control design. All other books on structure design and books on control design assume these are independent topics, but performance can be greatly improved if the dynamics of the structure and the dynamics of the controls are coordinated to reduce the control efforts required to accomplish the system performance requirements.

Read it here, below, thanks to Deda Mraz on Scribd.

Tensegrity

Tensegrity Sea Cages

2010-10-09T21:12:00.000-07:00

Something fishy is going on in tensegrity structures--fishy as in fish tanks, or to be more precise, underwater fish cages. Robert E. Skelton and SINTEF are joining forces to further the development of this approach to underwater confinement. SINTEF runs the Ocean Space Center, image at right.

All this fishiness started with Wroldsen's patent for a "Marine Structure For A Fish Cage For Aquaculture With A Net Spanned By A Tensegrity Structure". To quote the introduction,

The present invention relates to design concepts for flexible marine aquaculture structures. An extraordinary freedom to control shape, motion and vibration can be achieved by designing the system as a so-called tensegrity structure and by introducing appropriate actuation, sensing and control. A tensegrity structure comprises compressive elements like rods, and tensile elements like lines or wires. The invention also comprises interconnected units of flexible offshore structures.

The invention includes a series of actuated ring structures, based on octahedral cells like those Passera & Pedretti deployed for the Blur Building, Swiss Expo, 2001, and local energy production by means of motion actuated generators.

The whole idea of tensegrity cages is in the news again, as Skelton is advising Trondheim scientists on tensegrity structures, as part of NTNU and SINTEF’s marine research groups. They are focusing on marine tensegrity deployments as part of the IntelliSTRUCT project which is being financed by the Research Council of Norway. The aim is to lay the foundations for a new generation of sea-cages, trawls, vessel hulls and platforms. The researchers envision slender, intelligent structures that adapt to wave loads instead of fighting them. The SINTEF site wrote,

One of the aims of the Trondheim scientists is to develop 'smart' sea-cages for fish farming. They are already thinking of the challenges that await the aquaculture industry when it has to venture into the open sea in order to find enough room to expand. Sea-cages for use at sea will need to be able to withstand all sorts of weather. Traditionally, designers have enabled marine structures to withstand loads by making them strong. Smart structures represent a different philosophy of design, one that prefers adaptation and cooperation to raw strength. If necessary, a smart aquaculture sea-cage will change its own shape, so that it reduces the cross-sectional area that it presents to the waves. If there is little current and thus relatively little oxygen available to the fish, it will increase the area turned towards the direction of the waves.

Tensegrity researchers are also reminded of tensegrity cages deployed on land. See Alexy's tensegrity zoo cages, for example, as http://tensegrity.wikispaces.com/Alexy,+Christian or http://tensegrity.wikispaces.com/Animals

Links:

http://www.helseuniversitetet.no/Home/News-and-events/Research-News/Tensegrity--space-technology-in-the-ocean/

Tensegrity Supports A Fan In A Tree House

2010-10-09T20:57:00.000-07:00

In Shanghai, Madrid's Air Tree has

a tensegrity at its top, the cherry on a sundae of innovative architectural concepts. The structure is largely tensile in construction. It hosts a small arboretum--that means a tree garden--enabling urban dwellers to stumble acrosss a small forest in their concrete jungle. The trees create a micro-environment that includes lower ambient temperature.

The Air Tree is to be a main fixture of EcoBoulevard of Vallecas, Madrid, and was first installed at the Madrid's pavillion at the Shanghai World's Fair 2010. Inhabitat wrote,

‘Ecoboulevard’ for industrial revitalization won the AR Awards for Spanish Architecture group Urban Ecosystems. Aside from their aesthetic appeal, the trees have a very interesting benefit for the local residents who have to suffer through hot Spanish summers. The surrounding environment near the air tree will be naturally conditioned, reducing the heat island effect found in most city centers. The air trees will be implemented city wide in the coming years.

Some of the texts claim

that the fan at the top is suspended by a tensegrity structure. It is hard to tell from the pictures, but their are certainly a lot of cables up there.

Ventilation inside the Air Tree is provided through a big fan of 7.3m diameter, suspended by a tensegrity
structure in the centre of the space, at a height of 11.5m. Through a telescopic system the fan can be lowered several meters to be located closer to the visitors. The exact position and speed at each moment is determined according to the climatic conditions of the env
ironment that are monitored continuously in the surroundings of the structure.

Eco Sistema Urbano designed the project. They wrote,

The proposal for the Eco-boulevard of Vallecas can be defined as an operation of urban recycling that consists of the following actuations: the installation of three social revitalizing air-trees placed along the existing urbanization, the densification of trees within their existing concourse, the reduction and asymmetric disposition of the traffic routes, and superficial interventions within the existing urbanization (perforations, backfill, paint, etc.) that achieve reconfiguration of the executed urban development. Three pavilions or air trees function like open structures to multiply resident-selected activities. Installed in the non-city as temporary prostheses, they will be used only until air-conditioned spaces are no longer needed, when the area becomes 'fixed'. When a sufficient amount of time has passed, these devices should be dismantled, leaving remaining spaces that resemble forest clearings. The air tree is a light structure, easily dismantled and energetically self-sufficient, that only consumes what it is capable of producing by means of systems designed to capture and use solar photovoltaic energy... The bio climatic trees are an initiative to create a public habitable space to encourage relations between citizens. It also serves to generate a structure of neighborhood management. The climatization system of evaporate transpiration used in the tree and the immediate surroundings decrease in temperature up to 8-10º C.

The Air tree is also interesting due to its connection with Second Life. Curator Cristina García-

Lasuén selected it for the pavillion. Cristina planned the exhibit as her virtual alter-ego Aino Baa, a resident of Second Life very active in the machinima movement.

You are invited to see this tree house at the Shanghai Expo, to October 31st.

You can see the fan spinning at 0:13 in this video:

Links

ecosistemaurbano site, http://www.ecosistemaurbano.org/portfolio/cargador_en.html

Official site with many videos, http://www.madrid2010shanghai.com/videos.asp

World Architecture report, http://worldarchitecturenews.com/index.php?fuseaction=wanappln.projectview&upload_id=14901

Second life perspective, http://profilemagazinetoday.com/2010/05/03/second-life-machinima-going-to-the-world-expo-2010-shanghai-with-aino-baar-founder-ofopen-this-end.aspx

Inhabitat article, http://www.inhabitat.com/2008/01/24/stunning-air-trees-only-byproducts-are-h2o-energy/

Youtube: http://www.youtube.com/watch?v=6jOWaKrmXaw&feature=player_embedded

Nexorades And Tensegrity

2010-10-09T20:50:00.000-07:00

Nexorades are a new name for an old class of interwoven space structures also known as a multi-recip

rocal grid. Each of the elements of a nexorade is referred to as a nexor. The term nexor is a Latin for link, so nexorade implies an assembly of nexors. Each nexor has four connection points, two at the ends of the nexor and two at two intermediate points along the nexor's body. The nexors are interwoven and the system can be erected quickly using simple c

onnectors. Playing with nexors yields an entire family of lattice space structures that can be quickly assembled and deployed. The hypar-tensegrity Georgia Dome, by Mathys Levy and Weidlinger Associates 1992, is based on such a structure.

We tensegrity researchers have considered reciprocal frame structures before, as they are clearly sisters to tensegrity structures. Rinus Roelofs was a leading researcher in these structures, tracing them back to a drawing in Leonardo Da Vinci's notebooks. A nexor looks very much like a tensegrity cells--that notion of a strut that has its tendon firmly attached, like the Tensegritoy struts.

Here is a short review of nexorade work:

Olivier Baverel and Hoshyar Nooshin are two researchers publishing work on nexorades. Nexorades require sophisticated CAD tools and algorithms as their geometry is rather difficult to work out. Baverel, at the Surrey Centre for Engineering Structures and Materials, proposes a genetic method for working out nexorades, similar to that used for regularisation of member lengths of a lattice space structure. This method for the shape finding of nexorades is now available through a standard function in the programming language Formian. See http://www3.surrey.ac.uk/eng/research/ems/ssrc/projects.htm. In another publication, Baverel proposes a "fictitious mechanical behaviour" to solve the form-finding problem. He writes, "The dynamic relaxation algorithm is used with a model that takes into account the eccentricity between the elements. Its implementation is explained and its versatility is illustrated through several examples covering various fields of applications going from form-finding problems to non-linear structural analysis of structures." In this article he compares the structural behaviour of nexorades is compared with more conventional triangulated structures. See here.

TaffGoff, a leading SketchUp artist, has posted some nexorades. See http://forums.sketchucation.com/viewtopic.php?f=81&t=31501

Links

For a good overview of tensile structures that includes truss systems, tensegrity and nexorades, see Sebestyen, Gyula. 2003. New Architecture and Technology. An excerpt is hosted here: http://arch-tour.blogspot.com/2009/04/space-structures.html. It can be downloaded here, http://www.scribd.com/doc/28761510/New-Architecture-and-Technology

Article by Baverel in Nexus Journal, readable in Google Books online, http://books.google.com/books?id=pMvG5_H5wDUC&pg=PA280&lpg=PA280&dq=nexorade&source=bl&ots=LXe71bCTXd&sig=NkZd7sIZOOD4dJbwrOM-re3PElc&hl=en&ei=L_evTLavM8fNswbW7NTZDQ&sa=X&oi=book_result&ct=result&resnum=8&ved=0CDUQ6AEwBw#v=onepage&q=nexorade&f=false

Tensegrity Wind Turbine

2010-10-07T09:27:00.000-07:00

Hugh Thomson posted a CAD diagram of a tensegrity wind turbine atop a Skylon-like pedestal. I think his deployment of membranes on a tensegrity is a very promising direction, and thank him for sharing the simple and beautiful rendering, reproduced here.

Tensegrity fans often work with alternative energy. Marjetica Potrc, for example, made sure to include a wind turbine near her tensegrity-shack. In her "Burning Man: Tensegrity Structure and Waterboy" she wrote,

This tensegrity structure... is made from long wooden poles and cord; its stability is solely the result of tensegrity, the balance of push and pull. The shelter is upgraded with self-sustainable technologies, such a

s a solar canopy and a wind turbine, which power the water pump that serves the Waterboy, designed by Marque Cornblatt for the Burning Man Festival.

Oobject hosts a list of the most beautiful wind turbines, many of which deploy tensile technologies, though not purely tensegrities. Notable is the sea anchored blimp, pictured here. They wrote, "Selsam created a proposal for giant fields of fishing rod like turbines anchored on the sea bed and flexed against the wind. This proposal goes one step further to imagine the rod structures being held aloft by blimps."

Hats off to Thomson--while his model is clearly not fully functional, this direction of tensional, tensegrity sturctures with membranes, may hold a lot of promise. Contact him and please offer him suggestions: "hught2008" on gmail.com.

Links:

Tensegrity Wind Turbine by Thomson, http://spatialgeometrix.blogspot.com/2010/10/tensegrity-wind-turbine.html

Hugh Thomson's blog, http://spatialgeometrix.blogspot.com/

His models for sale on ebay, http://myworld.ebay.co.uk/photoencrypt

My previous post on Thomson, http://tensegritywiki.blogspot.com/2010/09/shug-thomson-engineer-and-artist.html

Sea anchored blimp, http://www.oobject.com/beautiful-wind-turbines/sea-anchored-blimp-flown-superturbine-concept/1325/

Jewish Tensegrities

2010-09-25T10:31:00.000-07:00

The sukka, a temporary outdoor dwelling, is constructed annually by practicing Jewish people during the Festival of Tabernacles. An autumn celebration, the holiday and its dwelling have many religious and mystical associations. One unusual aspect of the week-long festivity is dwelling--eating, studying, and sleeping--in a sukka, defined as a temporary edifice where you feel the wind and can view the stars through its shabby, temporary construction.

Innovative upholders of this ancient Jewish tradition are hosting a Sukka City contest in New York City, where they deployed some creatively modulated and adorned booths. The exhibit stands in Union Square Park until the close of the holiday, September 21st.

Of interest to us, of course, is the tensegrity-based booths that were erected this year. A stand out is the proposed bamboo structure, a 5 modules of a 3 strut tensegrity mast called "Pillar of Cloud, Pillar of Fire" by Andrew Sternad, John Kleinschmidt. They write in their artistic statement,

The structural system is inherently economical and achieves a height of 20 cubits with the absolute minimum of material. Additionally, the entire structure can be constructed horizontally on the ground and rotated up into position. It can also collapse into a single bundle with the removal of certain key components. The structure can be thought of as a stack of self-supporting modules, each made up of three rigid poles and a series of cables. The module resting on the ground uses perforated tubular steel poles (which contain led strip lights and mounted spotlights) and steel cable. The modules above together represent the roof and use only organic materials: bamboo poles and hemp rope. Sheer nylon fabric stretches taut between selected facets of the structure.

And the winner is: "In Tension" by the Brooklyn firm SO-IL won a prize for best sukka. It is a 3 strut tensegrity with mesh walls and seats inside. A local newspaper razzed the entry, objecting that SO-IL already displayed this structure elsewhere. See here.

While these booths may not meet traditional Jewish specifications, it is exciting to see the tensegrity structures deployed by modern people adhering to such a venerable, ancient faith. What next? A tensegrity pagoda?

Links:

Wikipedia on this type of temporary booth, http://en.wikipedia.org/wiki/Sukkah

Sukkah city page featuring "Pillar of Cloud, Pillar of Fire" by Andrew Sternad, John Kleinschmidt,

http://www.sukkahcity.com/sukkah/pillar-of-cloud-pillar-of-fire.php

Human Scribbles blogged about the Sukka city and posted photographs, http://humanscribbles.blogspot.com/2010/09/simple-complexity-and-complex.html

Florian Idenburg plea for $10 on Architizer, http://www.architizer.com/en_us/projects/view/sukkah-new-york/12770/?country=en_us

Hammock Tensegrity Innovations

2010-09-21T03:14:00.000-07:00

David WV and John MacEntyre Allen lead the deployment of tensegrity structures for campers. MacEntyre is inventor and retailer of the MOLLE-based Molly Mac Pack, a human-carryable rig based around a double sided M.O.L.L.E. panel, with shouder straps, hip belt and webbing--as MacEntyre says, "a backpack without the pack." WV has long experience with tensegrities. He describes them as a wound-up spring. he wrote, "Think of a tensegrity as a big spring, because that's what it is. I'm guessing that the tighter you wind it, the more force it takes to make it move (but also the bigger the "Sproingg!" when it breaks.) Thank goodness for spectra. I once made tensegrities using 8' bamboo poles and nylon rope. When rolled down the mountain they would pick up speed and start to bounce. Very impressive." WV also made some cellular tensegrity kites using arrow blanks and 60 lb test spectra rope.

Hammock Morphology

The design focus in an N strut stand to support N hammocks, with a shade tarp over the top and a stove in the center. The structure would be back-carryable, meaning that some of the tendons would be detachable. The design is based on the 3 strut tensegrity tripod. The design is based on the following ratios:

A) Three struts and nine tendons (i.e. - the top and

bottom faces are triangles) The strut/tendon ratio = 1/0.68125

B) Four struts and twelve tendons (i.e. - the top and bottom faces are squares) The strut/tendon ratio = 1/0.6436

C) Five struts and fifteen tendons (i.e. - the top and

bottom faces are pentagons) The strut/tendon ratio = 1/0.60843

With a sufficiently wide base, it should be stable and still allow enough free space to hang the hammock.

Hammock Materials

Struts: steel pipe, as sold for chain link fence, and aluminum poles in 10' length. They are also trying bamboo, and military surplus synthetic sectional segmented antenna poles that are 11.5 feet long and weigh 6.4 lbs each, or carbon fiber (ultra lightweight, just 3 lb., but expensive, about $300 per pound). Aluminum: For example, texastowers.com offers 12' drawn aluminum tubing. In the prototype below the struts are 123". Sectional: WV wasn't sure the sectional rails would support a hammock, but they seem to be OK with his 150 lbs. weight, with no struts bending, not strain at the joints. MacEntyre raised a model on 1 7/8" diameter struts, multi-faceted and not round. Their unions were crimped, and reinforced with an outer sleeve.

Tendons: Amsteel, or whoopee slings. Or Spectra rope. Spectra is ultra-high molecular weight polyethylene (UHMWPE) fibers yield very high strength and cut resistant ropes that can stand-in for steel cables at one tenth their weight.

Fittings: The end fittings have been a challenge. They have used carabiners at the pole ends for mechanical advantage.

Tools: 2-ton "come along" (hand operated ratchet lever winch). The tendons may be fitted with winches ( like a spanish windlass) for tightening.

Attachment to the ground: when there is a small base, some models need to be staked to the ground. Without staking, there is instability when the load shifts. In other words, for a 3-strut hammock stand, all three occupants would need to board and de-board at the same time.

Misc: the shade structure would drain if the struts were asymmetric.

Stacking Two Tensegrity Modules

If I stacked one on top of another, connecting the struts of the top tensegrity to the midpoints of the top tendons on the bottom tensegrity, then both would need to be under considerably more tension to handle the weight of hammocks without deforming. One reason to try this would be to make the base wide enough that it wouldn't need staking at all. There are probably a number of reasons not to try this, but we won't know what they are until we do. Of course, if we use longer struts the base of a single tensegrity could be big enough to make staking unnecessary.

Connecting The Shade Tarp

While the shade is not essential to the tensegrity, it is important as this stand is likely to be deployed in an area without trees, hence the need for shade. MacEntyre is considering a three cornered tarp, quadrilateral on one side and triangular on the other... use bungie to connect the "ridgeline" reinforcement points of the tarp to "my" hammock's stuts, bungie the triangle side's corner to the opposite strut, with the line you describe running down to a single stake, and guy the quadrilateral side's corners down to stakes in the ground. Each additional hammocker does exactly the same thing with an identical tarp. If you are the only hammocker on the stand, keep a line from the top of a strut to the ground, with a bungee prussic on it to pull the tarp, pull the triangle side down through the middle of the tensegrity stand and guy it to a stake in the ground directly beneath the top of the opposite strut.

Hammock Tensegrity Videos

MacEntyre video tour of two 3-strut tensegrity stands with multiple hammocks, uploaded 4 September 2010 to MollyMacPack's YouTube channel.

Link: http://www.youtube.com/watch?v=GMGucHehKak

Assembling a Tensegrity Hammock Stand

The struts are 123" long, tendons are 7/64 amsteel. There was a lot of calculating and then trial and error tweaking to arrive at the lengths of the tendons and how to connect them, but now that's out of the way, and it's not difficult to assemble.

Link: http://www.youtube.com/watch?v=FS_o4PlQ_Jk

Contact:

MacEntyre (at) Yahoo (dot) com

Molly Mac Gear will have a tensegrity stand product soon, complete with segmented aluminum struts, color coded tendons, and a modular tarp

Links:

http://www.hammockforums.net/forum/showthread.php?t=20209&highlight=Update+Tensegrity+Stand+People

Rocket Ships Are Tensegrities

2010-09-20T14:15:00.000-07:00

NASA's Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. It is essentially a smaller version of the Atlas, that is, a lightweight "stainless steel balloon" tanks whose structural rigidity is provided solely by the pressure of the propellants within. To keep the tanks from collapsing prior to propellant loading, they were either kept in "stretch" or pressurized with nitrogen gas. As such, these rockets are pneumatic structures, and so they qualify as being tensegrities.

Pneumatics in general is the study, application and use of pressurized gas in structures and manufactured devices, usually to affect mechanical motion. Pneumatics is significant to tensegrity structural study as the pneumatics of pressurized, inflatable, flexible membranes are considered as an ideal model of a prestressed tensegrity structure. The membrane plays the role of the tension network while the isolated, rapidly moving molecules of the compressed gas play the role of the compression struts. The two classic examples are balloons and pneumatic tires.

Pneumatics are also used in dynamic tensegrity structures to extend and collapse adjustable length struts. Sterk has written about pneumatics in dynamic structures here.

Of course, such pneumatic rocket ship structures are not to be confused with the growing literature on deployable tensegrities in space, such as "Concept of Inflatable Tensegrity for Large Space Structures" by Hiroshi Furuya, Makiko Nakahara†, Satoshi Murata‡, Daisuke Jodoi, Yuzuru Terada, and Keiki Takadamak from the Tokyo Institute of Technology, Yokohama, Kanagawa, Japan, presented at the 47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference held 1 - 4 May 2006 in Newport, Rhode Island, here. The former are for blasting off into space, the latter are for being in space.

Many thanks to sanman for reminding me of the importance of pneumatics: I updated the page in the wiki. Also, for those who missed it, check out the pneumatic girders made by Tensairity.

Links:

The forum thread, http://forum.nasaspaceflight.com/index.php?topic=22247.0#msg617472

Centaur at Wikipedia, http://en.wikipedia.org/wiki/Centaur_(rocket_stage)

More on pneumatics, http://tensegrity.wikispaces.com/Pneumatics

Shug Thomson, Engineer and Artist

2010-09-15T12:58:00.000-07:00

Selling his tensegrity sculptures now on eBay, Shug Thomson joins Bruce Hamilton and others in marketing his tensegrity models. The auction links below will expire soon, but I will contact Shug and get a more permanent address to post here.

Links:

Shug Thomson Ebay page, http://myworld.ebay.co.uk/photoencrypt

Mark Hamilton's Tension Designs, http://www.tensiondesigns.com/home.html

Octet Ring Supports 3 Layer Tensegrity Roof

2010-09-12T10:32:00.000-07:00

La Plata, in Buenos Aires, Argentina, is a 53,000-seat capacity stadium

originally opened in 2003, formed from the intersection of two 85 m circles, with 48 m between their two centers.

Designed by architect Roberto Ferreira, the stadium is receiving a 312,545 square-foot tensile roof featuring Birdair’s steel cable systems and PTFE, a Teflon®-coated woven fiberglass membrane. Around the perimeter is the octet steel tube compression ring consisting of 45 octahedron/tetrahedron modules, forming a load bearing ring that will support the roof.

The top chords of this ring are the starting line for a dome formed by a triangulated cable network. The network features tensioned steel cable hoops at three different levels, together with vertical columns, diagonal cables, and ridge cables, thus deploying a pre-stressed tensegrity design. True to its tensegrity deployment, PTFE panels will be added as cladding, and will not play a supporting function (as they do in the Bird's Nest Stadium, Beijing); instead, the panels will be cabled tight within the tensegrity structure, pulled stiff in the same way that a drum head is tautened.

As the site develops, please post details to the wiki, here: http://tensegrity.wikispaces.com/La+Plata+Stadium

Thanks to Nacho_7 for bringing this to our attention. His original post here: http://www.skyscrapercity.com/showthread.php?p=63518865

Links:

Birdair, http://www.birdair.com

Official stadium website in Spanish, http://www.estadiolp.gba.gov.ar/

Pages on the roof at that website, http://www.estadiolp.gba.gov.ar/index.php/component/content/article/13-foto-central/84-el-techo-del-estadio-ciudad-de-la-plata

72 Tensegrity Articles out of 13 Million

2010-09-07T21:04:00.001-07:00

Look how important tensegrity is to the scientific community! Tensegrity, like a vitamin, is critical to human health: a small dose goes a long way.

72 tensegrity papers are hosted on this website, among its other 13 million papers. 72 papers out of 13 million, that is, about 0.0005% of the papers are about tensegrity. Sounds small--sounds tiny! Is it insignificant? Of course not. After all, a 75 kilogram man needs 15 mg. of zinc a day: that is, 0.002% of the man.

So get your minimum daily requirement today: click and download. Scientific Commons is a project of the Institute for Media and Communications at the University of St.Gallen, Switzerland.

A direct approach to design of geometry and forces of tensegrity systems (2006)

A General Class of Tensegrity Structures: Topology and Prestress Equilibrium Analysis (2007)

A method to generate stable, collision free configurations for tensegrity based robots (2008)

A mixed 0-1 programing approach to topology-finding of tensegrity structures (2009)

A Semidefinite Programming Approach to Tensegrity Theory and Realizability of Graphs (2008)

Active Tensegrity Structure (2004)

Adaptive civil engineering structures: the example of tensegrity (2007)

Adaptive force density method for form-finding problem of tensegrity structures (2006)

Adjustable tensegrity structures (2003)

Advances in the Optimization and Form-finding of Tensegrity Structures (2008)

An adaptable tensegrity structure for space exploration (2006)

An intelligent spatial tensegrity structure (2004)

Analysis of tensegrity-based parallel platform devices [electronic resource] / (2003)

Analytical and numerical investigations of form-finding methods for tensegrity structures (2007)

Application of the tensegrity principles on tensile textile constructions (2009)

Arcus as a tensegrity structure in the arolium of wasps (Hymenoptera : Vespidae) (2002)

Classification, analysis, and control of planar tensegrity structures for robotic applications... (2007)

Combining dynamic relaxation method with artificial neural networks to enhance simulation of... (2003)

Comparison between experimental tests and numerical simulations carried out on a tensegrity minigrid (2008)

Controversial Origins of Tensegrity (2009)

Deployable Tensegrity Reflectors for Small Satellites (2002)

Design of tensegrity structures using parametric analysis and stochastic search (2010)

Designing tensegrity modules for pedestrian bridges (2010)

Developing intelligent tensegrity structures with stochastic search (2002)

Domain decomposition approach for nonsmooth discrete problems, example of a tensegrity structure (2007)

Dynamic equations of motion for a 3-bar tensegrity based mobile robot (2007)

Effects of member loss on the structural integrity of tensegrity systems (2009)

Evolutionary form-finding of tensegrity structures (2005)

Exploring Continuous Tensegrities (2007)

Exploring Continuous Tensegrities by (2007)

Folding/unfolding of tensegrity systems by removal of self-stress (2005)

Free-standing tension structures: from tensegrity systems to cable-strut systems (2004)

From graphs to tensegrity structures : geometric and symbolic approaches (2006)

From graphs to tensegrity structures: Geometric and symbolic approaches (2004)

Gait production in a tensegrity based robot (2005)

Geometry of configuration spaces of tensegrities (2008)

Growing Form-Filling Tensegrity Structures using Map L-Systems (2009)

JOURNAL OF MECHANICS OF MATERIALS AND STRUCTURES Vol., No., A MARCHING PROCEDURE FOR FORM-FINDING... (2008)

K.: Tensegric-Modeling-Based Soft Tissue Deformation for (2006)

Kinematic Analysis of Tensegrity Structures (2002)

Kinematic analysis of tensegrity structures [electronic resource] / (2002)

Learning and Self-Diagnosis of a Tensegrity Structure (2005)

Learning, Self-Diagnosis and Multi-Objective Control of an Active Tensegrity Structure (2006)

Mechanical behavior in living cells consistent with the tensegrity model

Modeling, design, and control of tensegrity structures with applications (1999)

Monitoring of full scale tensegrity skeletons under temperature change (2009)

MOTION CONTROL OF A TENSEGRITY PLATFORM ∗ (2008)

Multi-Objective Control of an Adaptive Tensegrity Structure (2005)

One-Story Buildings as Tensegrity Frameworks Des édifices d’un étage comme charpentes de... (1986)

Open-loop control of class-2 tensegrity towers (2004)

Parametric design methodology and visualization for single curvature tensegrity structures... (2004)

Practical Extension of Tensegric-Modeling-Based Soft Tissue Deformation (2008)

Second-order rigidity and prestress stability for tensegrity frameworks (1996)

Seismic behavior of tensegrity barrel vaults (2009)

Self-Diagnosis and Self-Repair of an Active Tensegrity Structure (2007)

Serviceability control of an active tensegrity structure (2005)

Serviceability Control of an Intelligent Tensegrity Structure (2004)

Simulating tensegrity systems with dynamic relaxation and neural networks (2002)

Symbolic Stiffness Optimization of Planar Tensegrity Structures (2008)

Tensegrities and Global Rigidity (2009)

Tensegrity Active Control: Multi-objective Approach (2007)

Tensegrity frameworks: static analysis review (2008)

Tensegrity Models and Shape Control of Vehicle Formations (2009)

Tensegrity modules for pedestrian bridges (2010)

TENSEGRITY STRUCTURES AND ECO-DESIGN: AS SOLUTION FOR THE REDUCTION OF ROW MATERIAL AND ENERGY IN... (2005)

Tensegrity structures for the Hellenic Maritime Museum (2010)

Tensegrity workshop: designing (the) building process (2009)

The role of the actin cytoskeleton in gravity signal transduction of hypocotyls of Arabidopsis... (2006)

The Theoretical Analysis of Self-Deployable Tensegrity Structures (1998)

Towards Intelligent Tensegrity Structures (2002)

Towards intelligent tensegrity structures (2003)

Two general methods for creating tensegrity structures of towers, arches, bridges and stadium roofs (2008)

Links:

The scientific commons: http://scientificcommons.org

St. Gallen University website: http://www.unisg.ch/en.aspx

Tensegrity Tower in an Emergency Blanket

2010-09-06T11:04:00.000-07:00

A new skyscraper model, built around 4 modules of a 3 strut tensegrity, will be wrapped in an emergency blanket by Cameron, Kassidy and Kelvin, students at the University of Auckland Faculty of Architecture. The blanket is cut and has zippers sewn on to as to form-fit the tensegrity.

Our new proposal keeps the same triangular formation as all previous modules. We want to keep the same prism-like shape formed by the tensegrity structures, but without the actual tensegrity units to hold the shape. The tensegrity idea was too dominant and did not merge in with the skin to make the structure as a whole. Therefore our solution to holding up the structure is to use inflation, blowing air into our skyrise.

Continuing with before, we will be sewing triangular pieces of emergency blankets together and also pleating them to give them strength. The connections of each triangular will be through strips of white fabric. The white fabric allows light to go through, and during the night this will act as a lead to attract people towards our skyrise. There will be numerous levels, around 10, of these triangles and will be connected through zips that run horizontally between each level. At the end, the module will have a triangular-cylindrical appearance held up by inflation.

Fairy Lights will be threaded in between the white strips of fabric so the whole structure will be one. Sandbags will be sewed and wrapped at the bottom to keep the structure heavy towards the floor so it would not fall over. We still need to test different methods of inflation which will be very interesting to see how it turns out. In due course, we will need to start finding sponsorships for materials. This includes emergency blankets, lighting, zips, white fabric, thread, needles, sewing machines, fans, air blowers.

Their post inspired me to finally add a page on masts to the wiki, here: http://tensegrity.wikispaces.com/Mast

Links

http://thetrianglecollective.blogspot.com/2010/09/03092010-studio-sessions.html

http://thetrianglecollective.blogspot.com/2010/09/23082010-mid-semester-crit.html

Tensegrity Masts on the India Skyline, 2020

2010-09-05T22:32:00.000-07:00

1000 square foot units hang from tensegrity towers, their roofs used for agriculture, their waste used to water lower level farms, and their waste in turn converted to biofuel to run the whole works. That is the winning proposal in the HP Skyline 2020 competition, open only to Indian citizens, as proposed by Anto Gloren, Sayali Athale and Pune. The jury wrote of their entry,

New image of future cities with high density but loose clustering. Very sociable and humane living. Circulation needs clarification. This seems the ideal direction for changing the skyline, not visual but really culturally and ecologically sustainable. Variable elevations of different clusters promise also a future visual delight. Vary attainable proposal without demand on high technology. Here is a winner!

I don't see the tensegrity masts, I see conventional 2x4s rectangular struts in their rendering, but maybe there are other renderings not published online. As we noted in past posts, for example in reference to bridges, it is not clear that a tensegrity mast would be the cheapest most efficient way to support such an overlapping complex of parallel planes, but i would sure like to see someone build it.

Links:

A good summary on TreeHugger,

http://www.treehugger.com/files/2010/09/hp-competition-winner-has-rooftop-farms-plugin-units.php

The winner announced,

http://www.bustler.net/index.php/article/winners_announced_in_hp_skyline_2020_online_competition/

Dew Water Collector Tensegrity Structure

2010-09-05T12:57:00.000-07:00

The DEWelectric water collector is supported on a tripod that is claimed to be structured in a tensgrity with the rest of the cooling tower. "These support legs become a tensegrity structural system enhanced by a protective shade covering device that collects and funnels water over the bowl shaped ‘rain space’ gathering area. The cooling effects of the tower clusters and shading devices creates comfortable places and subtle climatic shifts for people to gather and explore the passive systems of Yaz Island’s DEWelectric that benefits the entire region."

The tower draws dew from the air by a process based on biomimicry.

The Namib Desert beetle (genus Stenocara) survives in the harsh environment of the Namib Desert where only a half-inch of rain falls annually. In response to the arid environment, the beetle has developed a unique water collection mechanism. A series of small bumps on the surface of its wings enable the beetle to collect water from fog that forms in the early morning and blows across the desert floor. When the beetle positions its body at 45 degrees the fog collects on its back and runs down the wings to its mouth, supplying the animal with water necessary for its survival. Mimicking the Namib Beetle, each ‘water stalk’ condenser in DEWelectric is designed to draw water out of the air while simultaneously generating electricity and providing both fresh water and power to the region. Each condenser is constructed from a pneumatic tube that circulates fluid cooled by seawater. When the warm moist air reaches the surface of the tubes, water vapor condenses on the colder surface of the tower that is textured much like the beetle’s hydrophilic shell. The coolant is then returned to the sea in a closed loop system to be re-chilled by the sea. The delta in temperature around the chilled water stock towers creates a negative pressure that draws air down the column spinning a 7.5 kilowatt wind turbine that generates electricity to feed the grid as well as the pumps that draw the water from the sea to the condensers.

The cooling effect of the towers will create small microclimatic temperature zones as the wind moves through the site creating comfortable inhabitable outdoor places for people to occupy during even the hottest times of the year. In addition, the entire installation provides a safe environment for visitors to explore and interact in and amongst the ‘pneumatic condensors’ providing a means for people to learn about the rich possibilities of passive water and energy harvesting in a direct and experiential manner and gather around the celebration of water and clean power.

Links

The Land Art Generator Initiative: DEWelectric Blue-Green Field of Water Stalk Condenser Towers

Geschreven op 4-9-2010 - Erik van Erne. Geplaatst in Energie en Besparing, Water

http://www.stichtingmilieunet.nl/andersbekekenblog/energie/land-art-generator-initiative-dewelectric-vast-blue-green-field-of-water-stalk-condenser-towers.html

Tensegrity in 12 Languages

2010-09-02T05:23:00.000-07:00

Chanel markets their tensegrity-inspired skin cream in twelve languages. While their connection to tensegrity or tensile structures is nebulous at best, we can benefit from their writers, and present tensegrity in Arabic, German, English, Spanish, French, Japanese, Korean, Dutch, Polish, Russian, Mandarin Chinese, and Taiwanese Chinese. I think the languages are Japanese (日本語), Dutch (Nederlands), Spanish or Castilian (español or castellano), German (Deutsch), Mandarin Chinese (官話 or 北方話), Taiwanese Hokkien (臺灣話 or Tâi-gí 台語), Polish (Język polski, polszczyzna), Arabic (العربية al-arabīyah or عربي arabī). Too bad they missed Hebrew (עִבְרִית) since Shai Offer works out of there and some of his students publish in Hebrew.

Links: http://www.ultracorrection.com/

Tensegrity Staircase Made of Glass

2010-08-20T06:35:00.000-07:00

Cinderella's glass slipper has found its perfect mate, a glass staircase. “What’s unique about the staircase is that we don’t have any stringers in the conventional sense of two bending beams,” says Thornton Tomasetti’s Wilfried Laufs. “We prestressed thin cables like a harp from the floor to the ceiling and clipped the glass treads in between. There are no beams or slabs or walls in this system at all.” Instead, the inclined cables are tensioned against the floor and ceiling, where castellated steel beams receive the cable ends and transfer the loading over to the main building-structure columns." [1]

In the image above by Grimshaw Architects, on the left you see prestressed cables running from the floor to the castellated steel beams overhead carry the glass treads. On the right, a fish-bow truss beneath the treads provides lateral stability.

Laufs and his collaborators Valkai and Zdanius presented the staircase at Structures Conference 2010.

Transparent laminated safety glazing treads are bonded to local stainless steel fittings (Sentry-glass Plus autoclave lamination process) that are connected to thin stainless steel cables, pre- stressed in between the floor and ceiling of a specialty glazing shop fabrication facility in Long Island near New York City. The full flight is supported entirely bending- free (without any risers) and designed as a tensegrity structure, where tensioned cables transfer loading to treads in compression. The cables are placed in a poetic way with varying angles and integrated lighting next to each other that remind the user of musical harp strings, making the treads entirely 'flow within space'. Underneath the transparent treads is a single fish-bow truss that assures lateral stability and increases natural frequencies to an acceptable level, high enough to minimize staircase vibrations. From a structural engineering point of view, careful calculations were carried out, both for the glazed treads (assuming post- failure scenarios) as well as for the cable structure and required pre- stress levels (using special third-order form-finding software for cable structure analysis). From a precision manufacturing point of view, one single type of adjustable structural connection from cable to glass tread was invented to take all different cable angles in an economic and elegant way. The presentation will show the architectural intend, concept engineering design, all required calculations, fabrication and erection of this one-of-a-kind new transparent prototype staircase made in the US.

Links and references

Referred article on the staircase, Innovative Harp Staircase by George D. Valkai, Casimir Zdanius, and Will Laufs, ASCE Conf. Proc. 369, 226 (2010), DOI:10.1061/41130(369)226, http://dx.doi.org/10.1061/41130(369)226

[1] Shattering Myths About Glass, By Josephine Minutillo, p. 4. Accessed 20 August 2010 at http://continuingeducation.construction.com/article.php?L=5&C=674&P=4 © 2010 The McGraw-Hill Companies, Inc. All Rights Reserved

Tensegrity Model Oozes Movement

2010-08-19T08:10:00.000-07:00

A 21 strut tensegrity with a computer-driven air compressor, pneumatic valves and human-activity-tuned sensors was deployed by Yosuke Ushigome, a masters student in Informational Science and Technology at the University of Tokyo. He named it Archi/e Machina. In his words, it is a large tensegrity-based structure with sensors that activate changing tension members in its tendon net.

The hardware of Archi/e Machina can be divided into a sensing device and a spatial structure. The sensing device in the prototypes were either microphones or six infrared sensors. The spatial structure, based on tensegrity, was composed of aluminum pipe and steel wire. Pneumatic devices were used to dynamically modify the structure. Its software consists of PC programs such as Max/MSP patches, that can input the sensor data and actuate the pneumatic devices. The size of one prototype was 5m x 5m x 4m (WxDxH) for spatial structure and 1m x 1m x 1m for its background system.

Videos

Links

Archi/e Machina and structured creature from Yosuke Ushigome on Vimeo.

Ushigome's portfolio. http://www.cyber.t.u-tokyo.ac.jp/~ushi/wp/category/portfolio

His 21 strut tensegrity in "body ooze": http://www.cyber.t.u-tokyo.ac.jp/~ushi/wp/2010/04/body-ooze.html

Portal to tensegrity models, from 3 strut t-prism up to 60 struts and more: tensegritywiki

Tensegrity Under the Skin

2010-08-18T07:15:00.000-07:00

Jean Claude Guimberteau's remarkable images of living fascia are accompanied by a narration about tensegrity. Guimberteau is a surgeon who has spent the last 30 years working with fascia and muscular structures.

Guimberteau incorporates tensegrity in his larger concept of anatomical structure that he calls a sliding system. IN a recent abstract he wrote,

The mobility of our body structures is so intrinsic and natural to us that we tend to take it for granted. The very fact of being able to pinch your skin and lift it, then let it go and see it return to its initial shape and texture in just a few seconds may seem banal enough until you begin to think of all the elements involved. The same is true when you bend your fingers and think of the movement of the flexor tendon across the palm without external translation. For decades, scientists thought that the skin was simply an elastic structure with loose connective tissue and a more or less virtual space. However, in biomechanical terms, this explanation is very vague. These old concepts developed more than 50 years ago have evolved thanks to the impact of research at the microscopic level, and the global, mesospheric concept has been abandoned. And yet, surgical dissection in vivo demonstrates that there are only tissue connections, simply a histological continuum without any clear separation between skin and hypodermis, the vessels, the aponeurosis and the muscles. In fact, visible everywhere are structures, which ensure a gliding movement between the aponeurosis, the fat structures and the dermis. As they studied this system of gliding between the various organs, in particular at the level of the tendons, the authors noted the existence of a type of system composed of cables and veil-like structures that they term the Multimicrovacuolar Collagen Dynamic Absorption System (MCDAS). This system looks totally chaotic in organization and seems to function in a manner far removed from traditional mechanical structures. The functional unity of this sliding system is dependent upon a polyhedral three-dimensional crisscrossing in space of the microvacuoles, whose collagen envelope is type 1 or type 4 and whose content is made up of proteoglycoaminoglycans. The dynamic of this multimicrovacuolar system allows all of the subtle movements that occur within the body, thanks to its pre-stressed nature and the molecular fusion-scission-dilacerations that it is capable of. In this way, the system is mobile, can move quickly and interdependently, and is able to adapt is plasticity. This notion of microvacuoles is a fascinating one because it provides an explanation for the system’s space-filling ability.The matter is composed of elements. However, although they seem to be arranged in a haphazard manner, this is not the case. In fact, they occupy space in an optimal manner. If we accept this notion of microvacuoles, then it becomes possible to explain certain pathologies occurring with age, such as edema, obesity, aging and inflammation. This sliding system is to be found everywhere in the body and would seem to be the basic network of tissue organization.For this reason, it should be thought of in global terms. Since it constitutes the inseparable link and occurs in all living structures and at many levels, could it be that it the basic architectural design of Life?

Links

Dr. Guimberteau's website. http://www.guimberteau-jc-md.com/en/

The Skin Excursion (Le passage de l'epiderme) a continuation of the issues explored in the above film, sold at Tom Myers' website, http://www.anatomytrains.com/store/cat/dvds/45

Introduction to the sliding system, or Introduction a la connaissance du glissement des structures sous-cutanees humaines, Annales de Chirurgie Plastique Esthetique, Volume 50, Issue 1, Microchirurgie, February 2005, Pages 19-34, ISSN 0294-1260, DOI: 10.1016/j.anplas.2004.10.012. (http://www.sciencedirect.com/science/article/B6W8M-4F01165-1/2/429fe39bfd32b3b5df1de080bef50b90)

Tensegrity Card Trick

2010-08-18T06:22:00.000-07:00

Cards and pack float in this conjurer's application of the art of tensegrity. The magical card structure built by the magician is non-intuitive because the audience is not used to tensegrity. Mike Anderson wrote,

After stumbling over Paul Harris' Principle of Tensegrity, (found in his Art of Astonishment Book), I haven't been able to stop playing with this idea and trying to come up with new ideas on how to use it. This is a picture of what the basic Tensegrity effect is. And no the cards are not glued together. Each card is a single card and you form this gravity defying peice of art right in front of your spectator. I did this for my mother last night along with a few other effects and she stared at this for 20 min, trying to figure it out. Its so devious you have to learn how to do it. You can add items like Drinking straws, rubber bands, anything you can think of to make it even more impossible. But what the pic is is a basic idea of what you can do with the principle. Tensegrity ins't magic per say but does border on the verse of impossibility.

Apparently, Patrick Snowden first popularized this trick. Below, a magician on a Japanese TV show builds this card structure and adds a drinking straw to it.

Links

Ellusionist website forum posting: http://forums.ellusionist.com/showthread.php?90792-Paul-Harris-Tensegrity&s=50a1b6cdcab39b47bc0afacc1e302913&p=819791#post819791

Paul Harris website, selling his DVD http://www.paulharrispresents.com/ta_box.htmwith this text:

Tensegrity: Patrick Snowden's strange improbably balanced card sculptures have been pumped up to a new gravity-defying level. Can be done anywhere, surrounded, etc. A true piece of strange that leaves one dangling from the crumbling edge.

Ebay auction of the trick, from August 2010: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290464442479#ht_3634wt_1137 Buyer beware, read the reviews.

German Pride in Nano-Tensegrity

2010-08-15T22:34:00.000-07:00

Munich's Center for NanoScience, Cens, explains tensegrity in German in order to publicize the role that Tom Liedl played in building this amazing, tiny structure.

Tensegrity-Modell im Nanometer-Maßstab

Leicht wie ein Schleier scheint das Zeltdach auf den Säulen des Münchner Olympiastadions zu liegen. Seine Konstruktion beweist, dass stabiles Bauen auch mit geringem Materialaufwand möglich ist. Entscheidend hierfür ist eine optimale Kräfteverteilung: kompressionsresistente und zugstabile Bauelemente müssen so verteilt und miteinander verbunden sein, dass sich Druck – und Zugspannungen innerhalb des Systems ausgleichen. Auf diese Weise stabilisiert sich das Objekt selber. Das englische Kunstwort für dieses Prinzip ist „Tensegrity“, zusammengesetzt aus Tension (Spannung) und Integrity (Ganzheit, Zusammenhalt). Mit den weltweit kleinsten künstlichen Tensegrity-Strukturen beschäftigt sich Tim Liedl, seit 2009 Professor für Physik an der Ludwig-Maximilans-Universität München und Mitglied des Exzellenzclusters Nanosystems Initiative Munich (NIM). Während eines Forschungsaufenthaltes an der Harvard Medical School in Boston schafften es Tim Liedl und seine dortigen Kollegen erstmals, ein Tensegrity-Modell im Nanometer-Maßstab nachzubauen.

Links

Munchen University Center for Nano-Science Site, http://www.cens.de/index.php?id=261&tx_ttnews[tt_news]=755&tx_ttnews[backPid]=14&cHash=e8bc2e86fa

Post bragging about Tom Liedl's role, http://www.cens.de/index.php?id=261&tx_ttnews[tt_news]=755&tx_ttnews[backPid]=14&cHash=e8bc2e86fa

Proprioception and Tensegrity

2010-08-14T21:45:00.000-07:00

Tom Richards argues that tensegrity-based bio-informatics lies at the heart of human proprioception.

What if I were to tell you that your intelligence lies in much more than the thing between your ears? What if Iwere to tell you that there is intelligence in your muscles, fascia, and even your skin? These in fact are very important facets of a giant network of information gatherers that allow you to stand and move. You see posture is not a static “thing” that you just have. It is actually a dynamic state that is at every moment in a making micro-adjustments with the environment that it is working within. So at every moment 9.8 m/sec is pulling down on each segment of your body. In order to overcome this powerful ever-present force on us we must have a well-tuned highly intelligent network of information gatherers. When there is pain or loss of balance there is often confusion between the proprioceptive senses (the sense of the relative position of neighboring parts of the body) of the nervous system and the corresponding area of the body. A recent study showed a high correlation between scoliosis and diminished proprioception.

He goes on to explain tensegrity, and concludes by suggesting Structural Integration (or Rolfing) is the cure.

As much as tensegrity protects us it can also become disturbed by trauma and cause problems in the structural balance as well as our proprioception (awareness of spatial position and movement of the body). Tensegrity feeds back into the information gathering system. If don’t have the proper tensegrity to support our bodies we don’t have good proprioception. We begin to think that back is forward and crooked is straight. I have had many clients tell me that they feel self conscious about their rear end sticking out behind them when it is plainly tucked under them and actually causing pain in the back. It is not their brain that misinformed them. It is the information gatherers that feed into the brain. Translation: you may end up with a body that is tired, weak, and literally doesn’t know where its parts are. That person is residing in a body that is not enjoyable to be in.

Hands-on work (Structural Integration) is really the process of going only where the work needs to be done on the tissues and treating them with specificity. As someone who has had a Yoga practice for many years now I will contend that it is the best exercise you can do for yourself. That said you can almost never stretch your way out of the problem. Lifting weights at a gym usually won’t help either. If you think that your body doesn’t have the proper tensegrity that I am talking about then Rolfing may be the answer.

I look forward to more detailed work linking proprioception signalling to tensegrity concepts, at all levels: cellular, organ and body.

Link

http://rolftoevolve.com/uncategorized/tensegrity-proprioception-and-pain-oh-my/

Tiny Tensile Rods Signal Stem Cell Growth

2010-08-14T13:27:00.000-07:00

Tensegrity cellular researchers always contended, the tension components are both structural and bio-informatic, meaning that they signal critical information. The tiny, silly-putty-like rods in the photo were proven to signal stem cell growth patterns. This is important experimental proof that some inter-cellular communication happens using tensions between cells. The work was done at McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia. From the abstract:

Stem cells transit along a variety of lineage-specific routes towards differentiated phenotypes. These fate decisions are dependent not just on the soluble chemical cues that are encountered or enforced in vivo and in vitro, but also on physical cues from the cellular microenvironment. These physical cues can consist of both nano- and micro-scale topographical features, as well as mechanical inputs provided passively (from the base properties of the materials to which they are adhered) or actively (from extrinsic applied mechanical deformations). A suitable tool for investigating the coordination of these cues lies in nanofibrous scaffolds, which can both dictate cellular and cytoskeletal orientation, and facilitate mechanical perturbations to seeded cells. Here, we demonstrate a coordinated influence of scaffold architecture (aligned versus randomly organized fibers) and tensile deformation on nuclear shape and orientation. Sensitivity of nuclear morphology to scaffold architecture was more pronounced in stem cell populations than in terminally differentiated fibrochondrocytes. Tension applied to the scaffold elicited further alterations in nuclear morphology, greatest in stem cells, that were mediated by the filamentous actin cytoskeleton, but not the microtubule or intermediate filament network. With loading, nuclear perturbations were time- and direction-dependent, suggesting that the modality and direction of loading influence nuclear architecture. The present work may provide additional insight into the mechanisms by which the physical microenvironment influences cell fate decisions, and has specific application to the design of new materials for regenerative medicine applications with adult stem cells.

Credit:

Hats off to http://holykaw.alltop.com/silly-putty-scaffold-sizes-up-stem-cells for posting this first, and to Mr. Floating Bones Phil Earnhardt himself for bringing it to my attention.

Citation:

Mechano-topographic modulation of stem cell nuclear shape on nanofibrous scaffolds. by Ashwin S. Nathan, Brendon M. Baker, Nandan L. Nerurkar, Robert L. Mauck. Acta Biomaterialia, In Press, Accepted Manuscript,

Available online 13 August 2010, ISSN 1742-7061, DOI: 10.1016/j.actbio.2010.08.007.

http://www.sciencedirect.com/science/article/B7GHW-50S8PP1-5/2/f5da54691eb9bbcff5371df9341a2098

Keywords: Mesenchymal stem cells; nanofibers; nuclear orientation; anisotropy; cytoskeleton

Tensegrity According To Jáuregui

2010-08-09T23:22:00.000-07:00

Hats off for getting his book published! Valentín Gómez Jáuregui wrote this as his thesis, completed at the School of Architecture, Queen’s University, Belfast. It is an excellent and comprehensive survey of tensegrity with some interesting proposals for new structural directions.

Jáuregui's writing is clear and precise, and I learned a lot from his thesis. In particular, the Chronology of Tensegrity, one of the most popular pages on the tensegrity wiki, was based first on his work.

Links:

The book announcement: http://www.alumnos.unican.es/uc1279/Table_of_contents_Book.htm

Buy the book: http://www.libreriauc.es/ficha/publican/9788481025750/TENSEGRITY+STRUCTURES+AND+THEIR+APPLICATION+TO+ARCHITECTURE

Jáuregui's website: http://www.tensegridad.es/

6 Struts + LEDs = 2nd Prize

2010-08-09T05:46:00.000-07:00

Step on the pads and light up the tensegrity. This was the wayfinding method that Boston Architectural College students Oscar Anderson, Joshua Kirby, and Dan Lear proposed for the Common Boston Common Build competition.

This year the competition was devoted to Lost in Boston's agenda: wayfinding in the Boston area. Wayfinding encompasses all of the ways in which people orient themselves in physical space and navigate from place to place. This sense of place is eanbled by landmarks, signage, and objects that evoke a strong sense of center.

The 2nd Place Prize went to the 6 strut tensegrity pictured here. Stepping on the pads lit up LEDs to point out landmarks in Fort Point Channel. Judges thought the design was the "definite winner of innovation award for structure" and it "combined the notion of public art with the intent of way-finding."

Links:
Common Boston Common Build: http://commonboston.org/special-events/cbcb/

Lost in Boston: http://lostinboston.org

Pictures: http://thebacstudentdevelopmentblog.blogspot.com/2010/06/common-boston-common-build-bac-students.html
Announcement recap, http://thebacstudentdevelopmentblog.blogspot.com/2010/07/common-boston-common-build-competition.html

Fuller's Dictionary Online

2010-08-09T00:38:00.000-07:00

http://tensegrity.wikispaces.com/Synergetics+Dictionary now shows in one place the series of index cards Ed Applewhite filed on the subject of tensegrity. This is only possible thanks to R. W. Gray's herculean work uploading the dictionary to his website.

A sample card:

Link: http://www.rwgrayprojects.com/SynergeticsDictionary/SD.html

Tensegrity Explains Actin Formation In Cataracts

2010-08-05T08:57:00.000-07:00

F-actin production in rat's cataracts is best understood when the structure is considered in terms of tensegrity. The authors speculate that the rapid alteration of fiber end migration paths results in the F-actin being reorganized into configurations that help support and maintain the shape of the fiber ends, thus preventing their complete breakdown.

Similar to the concept of tensegrity in architecture, to balance the combined compressive and tensile forces that could potentially be acting on these fiber ends during phases of misdirected and/or uncontrolled migration, the F-actin could be rearranging itself into a structure that is tensegral. It is possible that the ‘rosette’ arrangement of F-actin seen during the initial cataract formation closely mimics a tensegral structure, rendering some semblance of stability to a rapidly deteriorating system. This would be especially advantageous in the fiber ends that are excessively enlarged and domed and could be the initial step that leads to the internalization and recovery of the lens previously documented in this animal model. Our studies indicate that lenses that develop dilated fiber ends stabilized by F-actin adopting tensegral configurations go on to recover by internalizing the cataract.

The authors are drawing on the growing body of evidence collected by Ingber and his colleagues. A decade ago they described the role of actin in this way

Established engineering and biological models of cell mechanics assume that the dense cortical microfilament network that lies directly beneath the cell membrane is the primary load-bearing element in the cell. In contrast, the cellular tensegrity model predicts that mechanical loads are borne by discrete molecular networks composed of interconnected actin microfilaments, microtubules, and intermediate filaments that extend through the cytoplasm and link to adhesion receptors, such as integrins, that span the cell surface. [1]

___

From "Abnormal fiber end migration in Royal College of Surgeons rats during posterior subcapsular cataract formation" By Anita Joy, Tabraiz A. Mohammed, Kristin J. Al-Ghoul.

Anita Joy is at the Department of Anatomy & Cell Biology, Rush University Medical Center, Chicago, IL; Tabraiz A. Mohammed is at the Department of Ophthalmology, Rush University Medical Center, Chicago, IL; he is currently at the Department of Medicine, University of Wisconsin Hospitals and Clinics, Madison, WI.

For more info, contact: Kristin J. Al-Ghoul, Ph.D., Department of Anatomy and Cell Biology, Rush University Medical Center, 600 S. Paulina St., Ste 507, Chicago, IL, 60612; Phone: (312) 563-2672; FAX: (312) 942-5744; email: kristin_j_al-ghoul -at- rush.edu

Link: http://www.molvis.org/molvis/v16/a159/

References:

[1] Mechanical behavior in living cells consistent with the tensegrity model by Wang et. al. www.pnas.orgycgiydoiy10.1073ypnas.141199598

Tensegrity Hammock Stand

2010-08-05T07:44:00.000-07:00

WV posted his hammock design to hammockforums.net in July 2010. He wrote:

The tendons are amsteel, and they need to be that strong. The tensegrity distributes the forces acting on it throughout the structure, and those forces are considerable. When you tighten that last tendon to assemble it, you're tightening all of them. How tight you make it depends on how springy you want it to be. It works fine in a slightly loose (springy) mode for hanging a hammock, but you still need to pull pretty hard. I loop the final tendon three or four times through the carabiners at the pole ends to get some mechanical advantage. The tool of choice would be a 2-ton come-along.

I used cast aluminum end caps for chain-link fence from Lowes.

The stand has a small base with one corner staked, not visible. You wouldn't need to do that with this stand if there were three hammocks on it and everybody got into and out of the hammocks simultaneously.

WV, if you are reading this post, give us more details in the wiki, "how to build a tensegrity hammock stand," please! Here: http://tensegrity.wikispaces.com/How+To+Build+A+3+Strut+Hammock+Stand

Mechanism As Mind: Tensegrity and Morphological Computation

2010-08-04T21:53:00.000-07:00

A soft robot design team defines mo

rphological computation as "the use of mechanism as mind". In "What Tensegrities and Caterpillars Can Teach" John Rieffel, Barry Trimmer and Hod Lipson address robotic locomotion via dynamic tensegrity structure.

They discuss that tensegrity embodies ”morphological computation,” where actuation and control of the structure is embodied within the structural dynamics of the robot itself.

The biological musculoskeletal system is thought to work in this way, as is cellular biomechanics. In this paper the authors review some details of a catepillar's anatomy and locomotion as it pertains to morphological computation. They then present related work in which a highly complex mechanical system – a tensegrity structure – is able to achieve locomotion by exploiting the dynamical coupling between modules as an emergent data bus.

The authors bring these aspects together when describing the design and control of a completely soft robot modeled loosely on the manduca. Their goal is to present morphological computation – the use of mechanism as mind – as the best approach to solving the issues of actuation and control inherent in soft robotics.

The examples of morphological computation that they bring - one from biology, the manduca sexta caterpillar, and one from engineering, a modular tensegrity tower - bring the design of a highly articulate, under-controlled, soft robot closer to fruition.

What Tensegrities and Caterpillars Can Teach Us About Soft Robotics by Rieffel, Trimmer, Lipson

Tensegrity Pin-up Girl

2010-08-03T12:36:00.000-07:00

Lydia is a 24 year old coed, she poses dressed only in her high heeled shoes. But this is no ordinary porn photo shoot. The camera in this case shines an X-ray beam that is captured by a photostimulable phosphor plate. After the plate is X-rayed, the excited electrons in the phosphor material remain "trapped" in "colour centres" in the crystal lattice until stimulated by a laser beam passed over the plate surface. The result, pornography for the tensegrity obsessed.

Okay, not so funny. But look: her bones are obviously compression islands, suspended in a omnidirectional network of fascial tension. And keep in mind: her tension network, distributed via body parts we have named tendons, fascia, etc, both coheres and signals information. That's my gal!

Wadhwani: Tensegrity and Membrane Integrator

2010-08-02T08:53:00.000-07:00

Wadhwani's unique explorations into combinations of tensegrity and membrane structures are very exciting.

Vishal Wadhwani (b. 1980) was trained at the Ahmedabad, India School of Interior Design, CEPT. He trained in steel and fabric structures at Kakani Associates before opening his own studio, "idea factor."

Now head designer of the firm he founded, he specilizes in tensile structures, and still has time for research into geodesic domes, tensegrity installations, origami/paper folding, and deployable systems. He also explores combinations of tensegrity & membrane structures to deploy kinetic/wind sculptures, and small kiosks & canopies. Currently he is working towards completing a masters in Membrane Structures at Dessau, Germany, combining tensegrity and membrane structures into one unit to develop some deployable systems. In these models, the tension cables are replaced by tensed membranes.

Links:

Wadhwani has a profile on Coroflot, here: http://www.coroflot.com/public/individual_details.asp?individual_id=93331&city=Ahmedabad&country=90&c=1&

His website: http://www.ideafactor.net

A workshop he ran, with many photos: http://tensegrityworkshop.blogspot.com/

Tensile Structured Chair

2010-08-02T08:30:00.000-07:00

Elastic bands in tension hold it together: no nails, screws or bolts.

Crosslegged chair was designed and built in 2006. Crafted with basswood, steel, reclaimed elastic bands. The Crosslegged chair was designed based on Japanese joinery. The structure comes together in a way that does not have any screws, nails or permanent joints. The chair holds itself together via tension and compression in mutual pre-stressed balance.

Wish I could see under that seat.

From Fishtnk. Link: http://www.fishtnk.com/tag/tensegrity/

Tensegrity Causes Headaches

2010-08-02T08:17:00.000-07:00

More and more healers, trained in Alexander Technique, Pilates, Rolfing, or Chiropractic, are preaching tensegrity as the way to comprehend the holistic nature of the human body. It is one of my ongoing delights to observe this way of thinking propagate messily throughout the blogosphere. Alex J. P. Boylan from Manchester, England recently posted a nice piece on headache care, and used the metaphor in a mixed way.

Is your headache really a pain in the bum?

Our bodies are always striving to stay in balanace, in fact our structural body IS in fact always in balance, or we wouldn’t be able to stand up without falling over. That doesn’t mean that we are always problem or pain-free however. The human body is what is reffered to as a tensegrity model, which basically means that any force acting on one part of the body is transfered to some degree to every other part. Within this model, there are certain structures which have relationship and effect each other greatly in keeping this balance.

But Boylan then contradicts this message with a traditional story of the stacked-up-spine.

At the base of your spine there is a wedge shaped bone call your sacrum, upon which the whole spine is stacked all the way up to your skull. The part of the skull which is at the base at the back is a bone called the occiput. The sacrum and the occiput basically have a very close inter-relationship which means that they mirror each others movement, and if one shifts in any direction the other will eventually move to keep the all important gravitational balance.

Maybe Alex J.P. Boylan BSc (Hons) MBAcC retreated from the metaphor to keep his reader engaged. Or maybe he his comprehension of tensegrity ends at a vague notion of holism, and does not extend to the idea of the myofascial network as a comprehension tension net that both integrates the body's tensegrity and propagates mechanobiological messages throughout the epi-hormonal system. Either way, his prose is proof that all the Skwishes sold to date, and all the Anatomy Trains workshops that have been held, are getting through to the general public, one strut at a time.

Link: http://www.re-creation.org.uk/all/is-your-headache-really-a-pain-in-the-bum/

Tensegrity in Polish

2010-08-02T04:10:00.000-07:00

As part of our service to non-English speakers, I paste below in its entirety a post by Justyna Michałkiewicz, permission pending.

TENSEGRITY TO ZŁOŻENIE DWÓCH POJĘĆ: ‘TENSION’ I ‘INTEGRITY’.

Tensegrity jest dopiero rozwijanym i stosunkowo nowym systemem (znanym od około 50 lat),dającym możliwość tworzenia spektakularnych, lekkich konstrukcji, sprawiających wrażenie zbioru prętów zawieszonych w przestrzeni.

Tensegrity bazuje na zastosowaniu elementów ściskanych, umieszczonych w sieci elementów rozciąganych w taki sposób, że komponenty ściskane (zwykle pręty) nie stykają się ze sobą, a wstępnie sprężone elementy (zwykle cięgna) nadają formę przestrzenną konstrukcji. Richard Buckminster Fuller ujął to obrazowo, mówiąc o współdziałaniu „wysp elementów ściskanych” otoczonych „morzem elementów rozciąganych”.

W TAKICH UKŁADACH PRĘTY NIE STYKAJĄ SIĘ
ZE SOBĄ, TWORZĄ SPÓJNĄ STRUKTURĘ JEDYNIE
ZA POMOCĄ CIĘGIEN

RYS. ELEMENTRNA STRUKTURA TENSEGRITY,
TZW. „SIMPLEX”

Tensegrity nie jest powszechnie znana strukturą, dlatego wiedza o mechanizmach i zasadach fizycznych, jakimi się rządzi nie jest zbyt rozpowszechniona wśród architektów i inżynierów. Jednakże jednym z ciekawszych i szczególnych aspektów systemu tensegrity jest jego geneza- kontrowersje i polemiki dotyczące odkrywcy.

TRZY POSTACIE SĄ UWAŻANE ZA TWÓRCÓW SYSTEMU:

• RICHARD BUCKMINSTER FULLER (PATENT 13.11.1962)
• DAVID GEORGES EMMERICH (PATENT 28.09.1064)
• KENNETH D. SNELSON (PATENT 16.02.1965)]
• ARIEL HANAOR

- BYŁY TO TZW. „SAMOSZTYWNE” SYSTEMY TENSEGRITY- „SELF-STABLE”,
WSTĘPNIE SPRĘŻONE.

KOLEJNE MODYFIKACJE IDEI TENSEGRITY PROPONOWALI:

• ZBIGNIEW BIENIEK- KSZTAŁT. STRUKTUR MODULARNYCH
• RENE MOTRO- „V- EXTENDER”
• DAVID GEIGER- „CABLE DOMES”
• DONALD E. INGBER- BIOTENSEGRITY

R. Motro (1987, 2003) pisze jednakże o wypowidzi Emmericha (1988), jakoby pierwszy bardzo prosty system proto- tensegrity („Gleichgewichtkonstruktion”) stworzył w 1920 r. Karl Ioganson/ Johansen.

Był to układ „Structure- Sculpture” złożony z trzech prętów, siedmiu linek i jednego cięgna nienaprężonego, służącego zmianie konfiguracji systemu, ale utrzymującego równowagę. Emmerich dodaje, że taki układ jest bardzo zbliżony do wynalezionego przez niego proto- systemu- „Elementary Equilibrium” z trzema prętami i dziewięcioma cięgnami. Mimo tego brak wstępnego sprężenia, które jest jedną z cech charakterystycznych tensegrity nie pozwala konstrukcji Iogansona na to, by była uważana za pierwszą ze struktur tensegrity.

Jedna z bardziej kontrowersyjnych spraw był trwający ponad 30 lat (!) spór między R. B. Fullerem i K D Snelsonem. Jak wyjaśnia ostatni w liście do R. Motro:

„Latem 1948 roku Fuller był nowym wykładowcą w Black Mountain College, równocześnie będąc charyzmatycznym i nonkonformistycznym architektem, inżynierem, matematykiem, kosmologiem, poetą (!) i wynalazcą (25 patentów w ciągu całego życia). Snelson natomiast był studentem sztuki, uczęszczającym na wykłady Fullera o konstrukcjach geodezyjnych. Zafascynowany wiadomościami, jakie posiadł tego lata, sam zaczął tworzyć trójwymiarowe modele.”

Jak wyjaśnia artysta: „Uzyskał nowy rodzaj rzeźby, która może być uważana za pierwszą strukturę tensegrity, jaką kiedykolwiek zaprojektowano. Kiedy Snelson pokazał swą rzeźbę Fullerowi, profesor uświadomił sobie, że jest ona odpowiedzią na pytanie, które nurtowało go przez wiele lat” (dokładnie 21!)

W tym samym czasie, lecz niezależnie, David Georges Emmerich, być może inspirowany strukturą Iogansona, rozpoczął badania nad różnymi rodzajami systemów: począwszy od tych bazujących na geometrii graniastosłupów po bardziej złożone struktury tensegrity, nazwane przez Emmericha „structures tendues et autotendants”= „tensile and self- stressed structures”.

„Z3-1 mat prismatique 4B racemique” www.frenchculture.org

Efektem jego poszukiwań były opatentowane struktury „reseaux autotendants”, będące tym samym typem struktur jakie badali Fuller i Snelson.

Nawet jeśli początkowo Fuller wspominał Snelsona jako autora odkrycia, po jakimś czasie zaczął uważać je za „swoje tensegrity”. Termin ten wprowadził w roku 1955 jako złożenie słów „Tensional- Integrity”, a sam fakt nazwanie nowego typu truktur pojęciem, które on sam wybrał, pozwoliło ludziom sądzić, że to właśnie jego odkrycie.
Snelson był wyraźnie zmieszany: z końcem 1949 roku Fuller pisał mu, że jego imię przejdzie do historii, by kilka lat później zmienić zdanie i prosić by na jakiś czas pozostał anonimowy. Taka sytuacja skłaniała Snelsona do egzekwowania własnego wkładu w odkrycie podczas wystawy prac Fullera w 1959 r. w Muzeum Sztuki Współczesnej (MOMA) w Nowym Jorku. Jego udział w tworzeniu tensegrity został uznany i ogłoszony publicznie.
Fuller uważał jednak zawsze, że tensegrity nie zostałoby nigdy wynalezione jako nowy rodzaj struktury, gdyby odkrycia Snelsona nie zauważył on sam. W rzeczywistości.Fuller nie wspomina nawet o swoim dawnym studencie sztuki w jednej z ważniejszych i bardziej znanych książek o tensegrity „Synergetics”, nie czyni tego równiej w swej korespondencji z Burkhardtem.

Kopuła R.B. Fullera w systemie tensegrity.

Któż zatem wynalazł tensegrity? Pewne jest, że odpowiedź nie jest jednoznaczna. „Synergia”- współdziałanie naprężeń rozciągających i ściskających - stworzona przez obydwu, studenta i profesora, stanowiła źródło i początek tensegrity. Choć sprawa autorstwa jest bardzo ważna dla obydwu, szczególnie dla Snelsona, który jako jedyny jeszcze żyje, możliwe, że lepszym byłoby poświęcić więcej uwagi możliwościom jakie daje struktura, nie zaś samemu sporowi.
Losy dwóch twórców potoczyły się zupełnie odmiennie.

Snelson, mimo że zaczął studia podstawowych pojęć i zasad, jakimi się rządzi tensegrity, podsumowując swe badania na własnej stronie internetowej - skupił się jednak na estetycznym i rzeźbiarskim aspekcie tensegrity. Unikał ściśle matematycznego i fizycznego podejścia, z uwagi na swoje artystyczne proweniencje. Taka postawa doprowadziła go do stworzenia wielu różnych konfiguracji- niekonwencjonalnych i niesymetrycznych i osiągnięcia imponujących rzeźb znanych na całym świecie..

Northwood III”, www.kennethsnelson.net “”El Olivo”,www.kennethsnelson.net

“Trigonal Tower”, www.kennethsnelson.net

„Dragon” www.kennethsnelson.net

SPOSOBY PODZIAŁU DWUNASTOŚCIANU ROMBOWEGO

Swój wkład w rozwój tensegrity ma również Polak- dr inż. Zbigniew Bieniek, pracownik naukowy Politechniki Rzeszowskiej. Odkrył on zupełnie nowe aspekty kształtowania tego typu struktur na podstawie wielościanów „quasi- sferycznych”. Bieniek proponuje np. podział dwunastościanu rombowego, na mniejsze bryły - czworościany.
Wspomniane wielościany służą autorowi do opisu budowy morfologicznej kilku typów elementarnych modułów tensegrity zw. „tensegrity extenders” (tzw. wypełniacze prętowo- cięgnowe). „Zgrupowanie odpowiednich czworościanów w specyficznych konfiguracjach oraz umiejętne zastąpienie ich krawędzi zestwami prętów i cięgien połączonych węzłami przegubowymi w wierzchołkach pozwala ukształtować kilka typów takich modułów.”

Przykładowe moduły bazujące na złożeniu czterech czworościanów typu II

Przykładowe moduły bazujące na złożeniu: a) czterech czworościanów typu III, b) dwóch czworościanów typu IV(+) i dwóch czworościanów typu IV(-) (rys. z pracy doktorskiej dr inż. Zbigniewa Bieńka)

Przykładowe moduły bazujące na złożeniu dwóch czworościanów typu III (rys. z pracy doktorskiej dr inż. Zbigniewa Bieńka)

przykład modularnej struktury tensegrity opartej na pierwszym module z poprzedniei ilustracjiprzykładowe dźwigary tensegrity (rys. z pracy doktorskiej dr inż. Zbigniewa Bieńka)

przykład lewo i prawoskrętnej wersji dźwigara tensegrity (rys. z pracy doktorskiej dr inż. Zbigniewa Bieńka)

struktura tensegrity utworzona ze złożęnia lewo- i prawoskrętnej wersji dźwigara trójpasowego (rys. z pracy doktorskiej dr inż. Zbigniewa Bieńka)

Przykładowy fragment konstrukcji nośnej hali sportowej o strukturze opartej na modułach tensegrity jednego typu (rys. z pracy doktorskiej dr inż. Zbigniewa Bieńka).

Przykłady struktur tensegrity V-EKSPANDER wg. Zbigniewa Bieńka

Przykłady struktur tensegrity V-EKSPANDER wg. Rene Motro

ARIEL HANAOR

Badania w dziedzinie tensegrity rozpoczął w latach 80- tych studiami nad geometrycznym ukształtowaniem dwuwarstwowych siatek tensegrity, tzw. DLTG (double- layer tensegrity grids) za pomocą wspomnianych już wcześniej „graniastosłupów” tensegrity- „T- prisms” .(generujących płaskie powierzchnie) oraz „ostrosłupów” tensegrity- „T- pyramids” (przy tworzeniu powierzchni zakrzywionych.

Hanaor w 1987 roku zdefiniował trzy zasadnicze typy połączeń modułów:

- Typ I- moduły połączone tylko węzłami:
Typ Ia – Typ I zastosowany do wielokątów o nieparzystej liczbie boków ( moduły prawo- i lewoskrętne), tworzące konfiguracje jednoznaczne
Typ Lb- Typ I zrealizowany w odniesieniu do wielokątów o parzystej liczbie boków- powstają konfiguracje symetryczne
- Typ II- moduły są powiązane ze sobą nie tylko węzłami, ale także częściami wielokątów „bazowych” tworzących moduł

Później nastąpił szereg badań dotyczących geometrii układów i testów z użyciem obciążeń. Przyniosły one m. in. takie stwierdzenia, że siatki trójkątne są bardziej sztywne od kwadratowych, przy podobnym zużyciu materiału oraz bardziej ogólne, mówiące o dużej odkształcalności tego rodzaju systemu, ale też niskim zużyciu materiału w porównaniu z konwencjonalnymi sztywnymi strukturami.
Konieczne były dalsze badania w rozważanej dziedzinie. Przełomem stało się przedsięwzięcie Rene Motro (1998)- Laboratoire de Génie Civil in Montpellier. Zaowocowało ono powstaniem takich elementarnych układów, jak ten oparty o tzn. „V expander” autorstwa Motro i Viniciusa Raducanu.

V- epander moduł jak w prototypie

Prototyp dwukierunkowej najprostszej struktury (będącej rozwinięciem modułu na il.) został zbudowany z końcem 2000 roku, przekrywając powierzchnię 82 m 2 konstrukcją o masie 900 kg. Stalowa struktura została skonstruowana według normy Eurocode3 dla 160daN/m2 zewnętrznego pionowego obciążenia. Było to dowodem zadziwiającej sztywności tego rodzaju siatek. Rezultatem wspomnianego wydarzenia było opatentowanie systemu przez Raducanu i Motro w 2000 roku. (ilustracja wyżej)

PATENT ARIELA HANAORA

Bio – tensegrity wg. Donalda E. Ingbera

NOMENKLATURA

Początkowo definicje poszczególnych układów tensegrity nie były w żaden sposób ustandaryzowane. Najprostszy z systemów posiadał kilka określeń: "simplex", "elementary equilibrium", "3 struts T-prism", "3 struts, 9 tendons", "twist element", "3 struts single layer", "(3,9;2,1)" i inne. Podobnie było z pozostałymi znanymi systemami.

Rezultatem takiego zjawiska była chęć stworzenia uniwersalnego, klarownego nazewnictwa. Pozwoliłoby to na sklasyfikowanie tzw. "floating compression" systems i usystematyzowanie informacji odnośnie tychże systemów.
Obecnie mozna spotkać się z kilkoma metodami nazewnictwa systemów tensegrity. Są one logiczne i zbliżone do siebie - bazują na definiowaniu geometrii za pomocą prostych, uporządkowanych zasad.

<> Williamson i Whitehouse (2000) stosują jedynie cyfry, średniki i przecinki ujęte w nawiasy. Rozpatrują ogólną klasę (N, S; P ,P ,..., P ) struktur tensegrity składających się z N ściskanych elementów (np. prętów) i S rozciąganych elementów (np. cięgien). Struktura jest M- rzędowa z P prętami przypadającymi na rząd. W tak zdefiniowanym zapisie struktura "simplex" jest określona następująco: "(3,9;3)".

<> Motro (2003) używa kodu literowo- cyfrowego (alfanumerycznego). Definiuje każdy element inicjałem jego nazwy- po nim występuje liczba odpowiadających elementowi pozycji:
n- Nodes (węzły)
S- Struts or compressed components (pręty lub elementy ściskane)
C- Cables or tensile components (cięgna bądź elementy rozciągane)
R- Regular system (system regularny)/ I- Irregular system (system
nieregularny); w zależności od wypadku,
SS- Spherical system (system homeomorficzny ze sferą); jeśli taki przypadek występuje
Wcześniej wspomniany już przykład- "elementary equilibrium" będzie wyrażony zapisem: "n6- S3- C9- R- SS".

KALSYFIKACJA

Pierwszą klasyfikację tensegrity stworzył prawdopodobnie Fuller i jego współpracownicy, jednakże był to jedynie główny podział na dwie klasy struktur:
<> "PRESTRESSED TENSEGRITIES" (wstępnie sprężone)- samostabilne (self- stable), dzięki istnieniu w nich wstępnego sprężenia (pre- exsisting tensile stress).
<> "GEODESIC TENSEGRITIES"- uzyskujące stateczność przy zastosowaniu form trójkątnych (w powiązaniu z geometrią geodezyjną).

Anthony Pugh (1976) opracował gruntowny katalog systemów tensegrity. Co prawda było to sporządzone prawie wyłącznie w powiązaniu z wielościanami, jednakże jest bardzo pomocne. Pugh najpierw opisał najprostsze struktury, zarówno 2D jak i 3D, w zależnośći od wzajemnego położenia w nich cięgien, złożoności elementów ściskanych (pojedyncze elementy lub ich grupy) oraz liczby warstw lub rzędu struktury. Później sklasyfikował trzy podstawowe metody łączenie prętów („patterns”), stanowiące podstawę do tworzenia systemu sferycznego i cylindrycznego:

· DIAMOND PATTERN
· CIRCUIT PATTERN
· ZIGZAG PATTERN

Ostatecznie w opracowaniu znalazły się również sposoby zespalania ze sobą poszczególnych modułów i opis konfiguracji większych struktur.

SPHERICAL SYSYTEMS (systemy sferyczne)

Systemy homeomorficzne ze sferą, tzn. wszystkie cięgna mogą być odwzorowane na sferę bez przecięć między nimi, pręty natomiast znajdują się wewnątrz sieci linek, tworząc rodzaj „sferycznej komórki” („spherical cell”)
· Rhombic configuration- wzór połączenia odpowiadający „Diamond pattern” Pugha. Nazwa rodzaju połączenia zdradza sposób jego realizacji. Każdy pręt systemu romboidalnego odwzorowuje najdłuższą przekątną rombu utworzonego z czterech niezależnych cięgien (wspomniany romb jest „zgięty” wzdłuż swojej dłuższej przekątnej).

„T- Prisms”- graniastosłupy tensegrity również są włączone do tej części. Tworzy się je bazując na zwykłych graniastosłupach: poziome i pionowe krawędzie są cięgnami, pręty stanowią natomiast przekątne boków graniastosłupa. Przy wprowadzeniu obrotu pomiędzy wielokątami podstaw uzyskujemy „tensegrity prism”.

„Circuit” configuration- w tej drugiej klasie elementy ściskane są realizowane w postaci układu prętów zamykających romb (tworzony przez cięgna i pręty) w pokazanym wcześniej układzię „Diamond pattern”

Kilka wielościanów foremnych (i nie tylko foremnych), może być zbudowanych w oparciu o tę klasę, np. cubooctahedron, icosidodecahedron, snub cube, snub icosahedron. Przedstawiona na ilustracji struktura cubooctahedron składa się z czterech „pierścieni” prętów (po trzy w „pierścieniu”), przeplatających się wzajemnie oraz cięgien stanowiących krawędzie wielościanu.

Circuit confifuration

„Circuit system” jest bardziej sztywny niż rombowy przy wykorzystaniu tej samej liczby prętów. Jest to zrozumiałe, gdyż wykształcił się z systemu „Rhombic”. „Circuit system” charakteryzuje to, że elementy ściskane stykają się ze sobą i występuje większe zagęszczenie elementów w stosunku do pierwotnego systemu.

· „Zigzag” configuration/ Type „Z”- konfigurację taką można uzyskać modyfikując system „Rhombic” tak, że poprzez usunięcie i dodanie kilku cięgien tworzą one kształt „Z”

„Rhombic system”

Typ Z

Należy zauważyć, że zamiana cięgien musi być spójna, jednolita, ze względu na stabilność systemu.

Przykład zmiany systemu na „Zigzag” pattern („expanded octahedron” jest przekształcany w „truncated tetrahedron”):

expanded octahedron”

„truncated tetrahedron”

Star systems (systemy gwieździste)

Systemy te to również „sferyczne komórki”, są jednakże uważane za klasę pochodną od sferycznej. Biorąc jako bazę np. jeden z systemów „rhombic” (przykładowo- „simplex”)- przekształcimy go w „star system” umieszczając pionowy pręt wzdłuż głównej osi symetrii i łącząc nowy element z pozostałymi cięgnami wielokątów podstaw. Można zaproponować też inny sposób- wprowadzając mały węzeł sferyczny zamiast centralnego pręta.

SYSTEM WYWODZĄCY SIĘ ZE SPHERICALSYSTEM
•MODYFIKACJA SYSTEMU RHOMBIC PRZEZ UMIESZCZENIE PRĘTA WZDŁUŻ GŁÓWNEJ OSI SYMETRII
•WARIANT Z WPROWADZENIEM SFERYCZNEGO WĘZŁA ZAMIAST PRĘTA

Cylindrical systems (systemy walcowe)

Są to również systemy wywodzące się z konfiguracji rombowej, uzyskane przez dodanie nowej warstwy prętów do pierwotnego systemu. Na ilustracji przedstawiono rozwinięcia wiązek prętów i cięgien pojedynczego modułu konfiguracji rombowej o czterech prętach oraz połączonych już modułów.

Jeśli „zwiniemy” tak powstałą siatkę z powrotem, otrzymamy cylindryczny maszt. Zależnie od liczby warstw powstała wieża będzie miała mniejszą lub większą wysokość.

Irregularl systems (systemy nieregularne)

Do systemu tego należą wszystkie konfiguracje, jakie nie mieszczszą się w wyżej wymienionej klasyfikacji. Duży procent rzeźb K. Snelsona jest zaliczany do nieregularnych struktur, gdyż nie rządzą się one żadnymi zdefiniowanymi zasadami.

INNE PRZYKŁADY

PRZYKŁADY ZASTOSWAŃ TENSGRITY

PIORUNOCHRON

STADION

PRZEKRYCIE

MOST - KŁADKA z wykorzystaniem modułów SIMPLEX

CIEKAWOSTKI

NASZ PROJEKT

KONSTRUKCJA NASZEGO ŁUKU OPIERA SIĘ NA POŁĄCZONYCH ZE SOBĄ DWÓCH RODZAJACH MODUŁÓW: PRAWO- I LEWOSKRĘTNYM

MODUŁY LEWOSKRĘTNE

MODUŁY PRAWOSKRĘTNE

OPRACOWAŁY:

JUSTYNA MICHAŁKIEWICZ (KRZYKWA) I ANIA MROZOWSKA

BIBLIOGRAFIA:

1. Tensegrity Structures and their Application to Architecture Valentín Gómez Jáuregui
http://www.alumnos.unican.es/uc1279/table_of_contents.htm

2 International Journal of Space Structures , volume 11 Numbers 1 & 2 1996 ,Special ssue on Morphology and Architecture

3. MOTRO, R. (2003) Tensegrity: Structural Systems for the Future, London: Kogan
Page Science.

4. http://www.kennethsnelson.net

5. BIENIEK:
* 2005, Kształtowanie modularnych struktur przestrzennych, Bieniek Zbigniew ;
* Examples of tensegrity structures composed of the polyhedral tensegrity extenders (Zbigniew Bieniek)

6. HANAOR, A. (1987) “Preliminary Investigation of Double-Layer Tensegrities”, in
H.V. Topping, ed., Proceedings of International Conference on the Design and
Construction of Non-conventional Structures (Vol.2), Edinburgh, Scotland: Civil-
Comp Press.

7. INGBER, D.E. (2003a) “Tensegrity I. Cell structure and hierarchical systems
biology”. Journal of Cell Science, No.116, pp.1157-1173
Also available in http://intl-jcs.biologists.org/cgi/content/full/116/7/1157
INGBER, D.E. (2003b) “Tensegrity II. How structural networks influence cellular
information-processing networks”. Journal of Cell Science, No.116, pp.1397 -1408
Also available in http://jcs.biologists.org/cgi/content/full/116/8/1397

8. EMMERICH, D.G. (1964), Construction de réseaux autotendants, French Patent No.
1,377,290, September 28, 1964
EMMERICH, D.G. (1964), Structures linéaires autotendants, French Patent No.
1,377,291, September 28, 1964
EMMERICH, D. G. (1966) "Reseaux", International Conference on Space
Structures, University of Surrey, pp.1059-1072.
EMMERICH, D. G. (1988) Structures Tendues et Autotendantes, Paris: Ecole
d'Architecture de Paris la Villette.\

9. FULLER, R.B. (1961) “Tensegrity”, Portfolio and Art News Annual, No.4. pp.112-
127, 144, 148. Also available in
http://www.rwgrayprojects.com/rbfnotes/fpapers/tensegrity/tenseg01.html
FULLER, R.B. (1962) Tensile-Integrity Structures, U.S. Patent No. 3,063,521,
November 13, 1962.
FULLER, R.B. (1975a) Non-symmetrical tensegrity, U.S. Patent No. 3,866,366,
February 18, 1975.
FULLER, R.B. (1975b) Synergetics: Explorations in the Geometry of Thinking, New
York: MacMillan Publishing Co., Inc. Also available in
http://www.rwgrayprojects.com/synergetics/synergetics.html
FULLER, R.B. (1981) “Tensegrity”, Creative science and technology, February
1981. Also available in http://www.bfi.org/infullerswords/Tensegrity.pdf

________________________

Accessed 2 August 2010 from http://justyna.adverhome.com/index.php?f=tensegrity

Devsuroop Singh's Winged Tensegrities

2010-08-02T02:18:00.000-07:00

I am not sure if they are tensile structures, classic tensegrities or both, but either way, Singh's designs are beautiful. These photos were uploaded by him, to Picasa, back in August 2007.

The silver strut he uses reminds me of the v-expander. A v-expander module is constructed from four equal length compressive members, six equal length outer tension cables and a central tendon. Its centre tendon is crucial as it stresses the whole structure, holds the form together and gives it rigidity.

Singh's compression member is curved, though.

Singh also built a tensegrity table, but you cannot see in the photo how the tension network is enabled.

Links: http://picasaweb.google.com/devsuroop9/TensegrityStructuresAndMore#

Double Helix Tension Mast in the Forest

2010-07-26T21:50:00.000-07:00

A tree-inspired tension mast has risen in "the Tuscany of Austria".

This observation tower by Munich office terrain:loenhart&mayr rises over the river Mur in Southern Styria, on the Austrian border with Slovenia, near Bad Radkersburg. It was engineered by the Office for Structural Design in Frankfurt.

It is a double helix tension structure composed of steel and clad with aluminum, by Klaus Loenhart, Director of the Institut für Architektur und Landschaft at Graz University of Technology and his colleague Christoph Mayr.

The supporting structure of the observation tower is designed like a tree. The lower part corresponds with a tree's trunk, while the steel structure of thinned-out tubes represents the more delicate branches up above. Its double spiral staircase boasts 168 steps that raise a visitor to a height of 27 meters. It has another flight going down. The tower sways as one climbs its stairs.

The tower was supported by local donors, whose names are inscribed on a plaque.

Client: Gemeinde Gosdorf Orts- und Infrastrukturentwicklungs KG
Design & planning of observation tower and exteriors: terrain:loenhart&mayr architects and landscape architects, Munich/Graz
Structural planning: osd – office for structural design, Frankfurt
Construction period: March – September 2009
Opening: 20 March 2010

Links
De Zeen Design Magazine article by Lilli Hollein
http://www.dezeen.com/2010/07/24/observation-tower-on-the-river-mur-by-terrainloenhartmayr

Resistance Training or Yoga? Only Tensegrity Can Help You Decide

2010-07-21T23:00:00.000-07:00

A yogi claims that resistance training builds tensional capability, while yoga promotes overall integrity. Not an earth shattering metaphor, but I always like a good tensegrity metaphor.

The overall health of the physical body, at least in terms of comfortable, efficient movement, boils down to the maintenance of tensional integrity. I say this because the word tensegrity itself is a contraction of the phrase, “tensional integrity.” This indicates to me a full integration of strength training and yoga posture practice is essential for maintaining a body that can move with strength and grace in any situation.

Resistance training, whether by picking up dumbbells, barbells, or even your own bodyweight, takes care of the tensional part, while yoga practice takes care of the integrity part.

Link:

http://yogaexercisetips.net/2010/07/21/which-is-best-yoga-or-strength-training/

Learning From Weaving in Architecture

2010-07-21T09:44:00.000-07:00

Indonesian weaving inspired the original tensegrity researchers, Fuller and Snelson. Their traditional Takraw ball was woven with a pattern cited by Snelson as similar to tensegrity structures.

Rizal Muslimin draws on such weaving traditions in the article he published in the latest issue of Leonardo, "Learning From Weaving For Digital Fabrication In Architecture". Muslimin formerly taught at the Bandung Institute of Technology, Bandung, Indonesia and now seems to be at MIT. His abstract:

This project restructures weaving performance in architecture by analyzing the tacit knowledge of traditional weavers through perceptual study and converting it into an explicit rule in computational design. Three implementations with different materials show the advantages of using computational weaving that combines traditional principles with today's digital (CAD/CAM) tools to develop affordable fabrication techniques.

The name Leonardo reminds me of Rinus Roelofs article on Leonardo roof grids, another woven surface that is a worthy study for students of tensegrity. Published by Kim Williams books, it features many images. Below, a grid by Roelfs, the author of that article and an intrepid tensegrity explorer. .

Links:

Leonardo website, http://www.leonardo.info/

The article is listed here: http://www.mitpressjournals.org/doi/abs/10.1162/LEON_a_00007

Rinus Roelfs article on Leonardo rooves, http://www.kimwilliamsbooks.com/leonardo/

Rinus Roelfs website http://www.rinusroelofs.nl/

Tim Tyler works with Leonardo space frames http://spaceframe.org/

The Clean and the Dirty in Tensegrity

2010-07-20T23:07:00.000-07:00

Dirty wins in Los Angeles Design Group's blog post last year on the pure and impure in tensegrity structures, a debate close to Tensegrity Wiki's heart. They find the dirty, or impure, provokes new developments.

Tensegrity systems have been co-opted by a kind of high modern discourse that privileges efficiency, balance, cellular repetition, and platonic forms. In this mode of thinking, tensegrity structures are valued for their purity, the way in which compression and tension are separated and are resolved into rational forms at the macro-scale. The strictness of this scheme has resulted in a problematic interface to the messiness of real architecture as designers attempt to accommodate complex programs and forms within the regime of the “pure” system. In other words, tensegrity is boring.

As the purity of this scheme is loosened, however, tensegrity structures can become sophisticated computing devices that allow complex exchanges between tension and compression to emerge. With this looseness also comes a shift in values. The pleasure of a “pure” or “perfect” tensegrity system is in observing the spatial array of tensile and compression forces: the beauty of being able to visually trace familiar engineering concepts in counterintuitive arrangements that seem to float. By contrast, the pleasure of a loosened or “polluted” tensegrity is in the way tension and compression are control devices that provoke the development of new morphological and material systems.

Put another way, tension and compression become interesting for the way they can do work that exceeds a structural capacity, but is at the same time driven by structural logic. In this way, experiments with matter can become “live” and “active,” energized by the activity of physics at play in the system. It’s time to reclaim tensegrity from the nerds.

Phil Earnhardt of FloatingBones adds some discerning differences,

Tensegrity makes more sense when weight is at a huge premium: deployable masts for satellites, etc. Another example: a deployable bridge for a Mars expedition: http://vimeo.com/4240683.

Sailboats are also a great example of a semi-tensegrity structure. Tensile forces are used to control the structure, but a pair of beams — the boom and the mast — touch each other. I could imagine the mast/boom constructed with tensegrity masts, but it would be a convoluted and probably a fragile structure.

The biggest reason for drawing the distinction is that there are certain structural behaviors that would apply to a true tensegrity but not for the semi-tensegrity structures. A true tensegrity is viscoelastic; Fuller describes that behavior in 724.32 – 724.34 of “Synergetics.”

"cy bish port street" agreed.

Purity as a criterion for design in tensegrity systems seems like a dead-end: we can catalogue all of the possible tensegrities that can be inscribed in prisms, spheres, and helical bounding geometries, but then what? Tensegrity becomes an encyclopedia of options, not a design principal. A more general approach — allocating tension and compression to separate ordering systems in a structure — seems to be more productive, allowing tensegrities to occasionally sacrifice purity in order to find a better “fit” with the demands of architecture and materiality. Tensegrity in biological systems seems like a particularly interesting case study because structural principals at play in the life sciences are often complex and excessive (in a good way); complex in terms of geometry, and excessive because material efficiency does not always appear to be the determining factor in how they emerge.

Continue the debate at the original post on LADG's blog, http://theladg.wordpress.com/2009/10/07/experiments-with-matter-can-become-live-and-active/, or below.

Bamboo Bridge, Tensegrity Hack, Being Built

2010-07-18T12:43:00.000-07:00

A one-hundred-feet long (33 meters) Bamboo Bridge is proposed by Michael McDonough, architect and designer. It features a polyten truss capable of supporting up to sixty times its own weight, and constructed of a unique high-strength Asian solid bamboo, steel cables, and connectors.

Located in a temperate redwood rainforest near Mendocino, California, it is being built to demonstrate the structural and aesthetic capabilities of bamboo as an engineered, high-tech material.

Michael McDonough keeps finding new ways to use the grass that is stronger than steel.

McDonough has worked with bamboo for years. An atrium he designed for the Sheraton Rittenhouse Square Hotel in Philadelphia, combined live bamboo plants, bamboo flooring and furniture, and tiles made, improbably, of soybeans and recycled paper. An architect and a designer of furniture, interiors, flatware, and jewelry--"from the spoon to the city," as he likes to say, quoting Adolph Loos--McDonough makes objects and spaces that address big questions about design and the environment.

Links

McDonough's website: http://www.michaelmcdonough.com/projects/spec/bambridge.php4

Andrea Moed covered McDonough earlier: http://www.metropolismag.com/html/content_0698/ju98bamb.htm

These Bones Were Made for Floating

2010-07-18T12:35:00.000-07:00

Alexander Technique teacher Ann Rodiger gives a warm, intuitive write up of the floating bones and sesamoid bones way of thinking... Nothing new here, but hats off to Ann for her accessible writing style.

Instead of thinking of our body as bones piled up and resting on top of each other (the post and beam or stack of plates system), the body is seen as a fluid and mobile structure capable of free and easy movement.

As we consciously lengthen our bodies and allow for the spaces between our bones, we can maintain the integrity of the tensegrity system.

Entertaining this way of understanding the body can change the way you experience your body.

Try this experiment:

First, as you sit or stand, think of your bones as supporting your body by resting on each other and thus compressing your body weight into the floor – how do you sense yourself?

Now conscious allow for space between your bones. Think of space between every bone, even between the bones of your head.

Add to that the thought of your body lengthen up out through your head, rebounding from gravity, and see how you sense yourself.

This is a good way to see how much our thinking changes how we move. Working with new ideas can reveal what we have been thinking in the past. Even if those previous thoughts have been unconscious we have been functioning from those principles.

At the recent AGM (Annual General Meeting of AmSAT American Society of the Alexander Technique) Carol Boggs gave a presentation where she quoted Dr. Stephen Levin who said that “all bones are sesamoid bones.” We played with this concept during Carol’s workshop and found that it significantly changed our experience of own body and balance.

Wikipedia says that in anatomy, a sesamoid bone is a bone embedded within a tendon. Basically our tissues thin and thicken into tendons, ligaments, and muscles. Fibers from one density flow into fibers with another density or elasticity. Our structure is continuous and fluid.

We suspend, we float, and we balance AND you can experience it!!!!

Ann Rodiger's Blog: http://balancearts.blogspot.com/2010/07/space-between-bones.html

And by the way, her skeleton's name is Bernie.