The simple
kite frame, two crossed struts held firmly together by a girth
of four tension members, is a human invention and probably thousands
of years old. Long before people covered it with paper for use
as a flying object to loft in the wind the frame most likely was
used as a lightweight pallet, a stretcher for transporting things.
Basic as it is, the prestressed kite exits only in the world of
people; not as a product of nature.
The kite
frame can be built in many proportions as shown below. The structural
principle remains the same except that the distribution of forces,
both tension and compression, vary as the proportions are altered.
Always, though, the total of the compression forces pushing out
are equal to the sum of the tension forces pulling in.
The kite
frame is quasi-tensegrity because the two struts, lacking a force
in the "z" direction in order to separate, touch and
press on one another where they cross. The kite structure is the
basic prestressed tension-compression cell for x-module tensegrity
structures.
The lengths
of the four tendons and the lengths of the struts determine the
shape.
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