Talk:Tensegrity
|
|
The following text has been removed for possible copyright infrongement. The text is identical to this page: http://www.synearth.net/TensegrityHtml/Tensegrity.html
== Yes, I have written permission to use this information in whole or in part. I am in the process of editing out the unnecessary parts. --Sv==
ah. ok. cool. YOu can restore the article from the edit history. Sorry about this, but we have to check for infringement. -- Tarquin 19:47 Oct 15, 2002 (UTC)
I uberunderstand - SV
The original author of that article you're importing understands that the parts of their article that are imported to Wikipedia will be released under the GNU Free Documentation License, right? -- Tarquin
Tensegrity is the pattern that results when push and pull have a win-win relationship with each other. The pull is continuous and the push is discontinuous. The continuous pull is balanced by the discontinuous push producing an integrity of tension – compression.
Push and pull seem so common and ordinary in our experience of life that we humans think little of these forces. Most of us assume they are simple opposites. In and out. Back and forth. Force directed in one direction or its opposite.
Buckminster Fuller explained that these fundamental phenomena were not opposites, but compliments that could always be found together. He further explained that push is divergent while pull is convergent.
Missing image
Tenseg1.png
Image:Tenseg1.png
Imagine pushing a yellow ping pong ball on a smooth table with the point of a sharp pencil. The ball would always roll away from the direction of the push, first rolling one way then the other. Push is divergent. Now imagine the difference, if you attach a string to the ping pong ball with tape, and pull it toward you. No matter how other forces might influence the ball to roll away from you, the string would always bring it to you more and more directly. Pull is convergent.
Another example from common experience occurs when we are pulling a trailer with our car. When I am driving uphill, I am pulling against gravity. The trailer converges nicely behind my car. If the trailer begins to sway, I can dampen it by increasing pull – simply increasing my acceleration. Now if I am driving downhill, the trailer may begin to push. This produces a strong side to side force – divergence. My trailer will begin to sway from side to side. Push is divergent. When the trailer begins to push us, experts advise us to accelerate our car in order to re-establish pull. Pull is convergent. The trailer will straighten out and we can congratulate ourselves for being good drivers. These then are the two always co-existing fundamentals of Universe – Push and Pull – Compression and Tension – Repulsion and Attraction.
Tensegrity Seeking the Gift Tensegrity TrustMark 2001 by Timothy Wilken
Tensegrity Theory Explained
A more common example of a tensegrity is a child's balloon. When we examine an inflated balloon as a system, we find that the rubber skin of the balloon continuously pullswhile the individual molecules of air are discontinuously pushingagainst the inside of the balloon keeping it inflated. All external forces striking the external surface are immediately and continuously distributed over the entire system. This makes the balloon very strong. We all know how hard it is to break a good balloon with a blunt blow. Molecules of air discontinuously pushing against the continuously pulling rubber skin of the balloon. Tensegrity — a balance of continuous pull and discontinuous push. The automobile tire is one of the strongest most durable inventions in the history of humankind. And few of us are aware that it is a tensegrity. It is the power of tensegrity in each tire that protects us from failure and blowout despite high speeds and long miles. A tensegritythen is any balanced system composed of two elements – a continuous pull balanced by discontinuous push. When these two forces are in balance a stabilized system results that is maximallystrong. The larger the system the stronger the system. Most of humanity knows of Fuller's discovery of the Geodesic Dome, but few realize that geodesic domes are themselves tensegrities: "The great structural systems of Universe are accomplished by islanded compression and omnicontinuous tension. Tensegrity is a contraction of tensional Tensegrity Seeking the Gift Tensegrity TrustMark 2001 by Timothy Wilken 3
integrity structuring. All geodesic domes are tensegrity structures, whether the
tension-islanded compression differentiations are visible to the observer or not.Tensegrity geodesic spheres do what they do because they have the properties of hydraulically or pneumatically inflated structures."2 We are all familiar with the geodesic dome at Disney World in Florida. The larger the tensegrity the stronger it is. Theoretically there is no limitation to the size of a tensegrity. Cities could be covered with geodesic domes Planets could be contained within them. The only limiting factors are the amount of materials and the degree of our technologies. As Harvard physician and scientist Donald Ingberexplains: "The tension-bearing members in these structures – whether Fuller's domes or Snelson's sculptures – map out the shortest paths between adjacent members (and are therefore, by definition, arranged geodesically) Tensional forces naturally transmit themselves over the shortest distance between two points, so the members of a tensegrity structure are precisely positioned to best withstand stress. For this reason, tensegrity structures offer a maximum amount of strength 2R. Buckminster Fuller, SYNERGETICS—Explorations in the Geometry of Thinking, Volumes I & II, New York, Macmillan Publishing Co, 1975, 1979 Tensegrity Seeking the Gift Tensegrity TrustMark 2001 by Timothy Wilken 4
for a given amount of building material."3
Biological Tensegrities My own search for tensegrities began in 1980. As a trained physician, my attention first turned to the human body. I recognized two tensegritiesinstantly which are systems of the human body. The muscle- skeletal systemis atensegrityof muscle and bone, the muscle provides continuous pull, the bonesdiscontinuous push.The forces between the bones and muscles are held in constant balance. This forms the basis for all of our physical mobility. The central nervous system also functions as a tensegrity. The sensory-motor systemis a tensegrity of sensory neurons and motor neurons. The sensory neurons always sensing information – continuously pullingand the motor neurons only occasionally involved in some motor action – discontinuously pushing. 3Donald E. Ingber, The Architecture of Life, Scientific American Magazine, January 1998 Tensegrity Seeking the Gift Tensegrity TrustMark 2001 by Timothy Wilken 5
Finding Other Tensegrities
However, my focus was above the cellular level. I wanted to understand how individual organisms related to each other and again I expected that the concept of tensegrity would help us understand. I was quite familiar with Alfred Korzybski's operational definitions of Plants, Animals and Humans as Energy-binders, Space-binders, and Time-binders. (Read Korzybski's
discussion in Manhood of Humanity _Chapter 3, Classes of Life.) So I then as I examined the three classes of life, I began looking for tensegrities. Plants –the energy-binders have their primary relationship with the sun. Their leaves are continuous pullingas they collect solar energy from the sky, but with the rotation of the earth and changes in the weather the sun only discontinuously pushesits radiation on to the leaves. •Photosynthesis-Radiationis the energy-binder tensegrity. Animals – the space-binders are usually fighting or fleeing. They are generally limited to two roles either as prey or as predator. The prey animals are continuous pulling predators to them. While the predators are only occasionally hungry. They discontinuously pushout seeking the occasional kill. Prey and predator must be in balance to stabilize the ecosystem. The larger the ecosystem the more stable it is. •Prey-Predatoris the space-binder tensegrity. An associate of mine, Ms.Leann Roberts, recognized that even our human sexual roles as Female and Male operate as a tensegrity. The femalewas continuouslymaking herself attractiveto pull on her male, but the malewas only occasionally interested and discontinually pushingtowards her for attention. Humans – or time-binders have the power of understanding. We develop understanding through education. The two roles of humans can then be seen to be Student and Teacher. I am continuously learning – continuously pullingin new information, but I am only occasionally teaching – discontinuously pushingout information to someone else. Tensegrity Seeking the Gift Tensegrity TrustMark 2001 by Timothy Wilken 6
•Student-Teacherthen is the time-binding tensegrity.
If we examine the three classes of life from the viewpoint of their relationships with each other, we can see that: Plants as the independent class of life have no relationship with each other. They mostly ignoreeach other and form no tensegrity. Animals as the dependentclass of life have a negative relationship with each other. They form an adversary tensegritywhere the prey is continuously at risk of being hurtand the predator is discontinuously hurting other. Humans as theinterdependent class of life can have positive relationships with each other. We can form a synergic tensegritywhere we are continuously being helpedand discontinuouslyhelpingother. Tensegrity Seeking the Gift Tensegrity TrustMark 2001 by Timothy Wilken 7
Animals and other biological structures are made strong by their tensioned and compressed parts. Muscles and bones act in unison to increase the strengthen the other. This kind of strength goes to the cellular level, and is a somewhat new understanding of biological structuring.
Tensegrity also refers to a means of creating structures, using rods and wires. The rods are always in compression and the wires in tension, the rods do not connect with each other but are held in place by the wires, no member is parallel or perpendicular. A completed structure resists pressure in one plane but compresses and then returns if subject to force in the opposing plane.
The concept was discovered by Kenneth Snelson at Black Mountain College in 1948, the term 'tensegrity' was coined for Snelson by Buckminster Fuller from tensional integrity. Snelson used the concept to produce sculptures such as his 18 metre high Needle Tower (1968). The idea was adopted into architecture in the 1980s with David Geiger designing the first significant structure - a competition hall for the Summer Olympics of 1988.