Tensegrity Half Cuboctahedron Datasheet


Copyright © 2003 by Bob Burkhardt

        Member Descriptions
        [name, end point names, weight (if in objective function),
        second power of length (if a constraint), member category,
        Obj/Con/Exc (put in objective function, use as a constraint or
        exclude from computations), flags]
        For assembly purposes, only the name and end point names are
        of interest.  The other information may be of interest after
        A Practical Guide to Tensegrity Design has been consulted.

# strut
<Member> strut     p2' p1  -1.0      0.0      1 Obj CalcClear Inelastic *

# side tendon
<Member> xlt       p1' p1   1.0      1/2      3 Con *

# bottom tendon
<Member> bottom    p2  p1   1.0      sqr(1.0) 2 Con *

# top tendon
<Member> top       p2' p1'  1.0      1/2      4 Con *


        In-Situ Member Lengths
        These are the lengths of the members when they are in place
        and prestress is applied.  The strut lengths are from
        screw-eye center to screw-eye center, as are the tendon lengths.
        These values are in model units.

    strut:      1.22474       xlt:     0.707107    bottom:            1
      top:     0.707107


        Relative Member Prestress Force Magnitudes
        These values are useful for developing an assembly
        strategy for the structure.  The tighter tendons are much
        easier to tie in place early on, while the looser tendons
        can be left to the last.  This information is also used
        to adjust tendon lengths since the measured length of a tendon
        will be shorter for a highly-stressed tendon with the same
        in-situ length as a tendon which is not so stressed.

    strut:     -1.22474       xlt:     0.707107    bottom:          0.5
      top:     0.707107


        Construction Lengths (in millimeters and halves)
        The construction length of a tendon is less than the in-situ
        length since when the tendon is measured off it isn't under
        any prestress force.  The construction length for the strut
        represents the length of the 5/16-inch-diameter wooden dowel.
        The tendons were made of braided nylon fishing line.
        Prestress forces were assumed not to affect strut lengths.
 
        Elongation of Tendon of Unit Cross Section
        Under Force of Average Magnitude (fraction)> .02
        Length Scale Factor> 170/1.22474
        Strut and Tendon Hub Adjustments - s;t> 6.5 3.5
        (The 6.5 mm adjustment for the strut is the amount
         the screw-eye center extends from the end of the dowel.
         The 3.5 mm adjustment for the tendon is half the outer
         diameter of the screw eye.)
 
        strut: 157 0       xlt:  89 0    bottom: 130 0       top:  89 0


ray trace of tensegrity half cuboctahedron
Tensegrity Half Cuboctahedron with Point Labels

structure file:  tprism/halfcubocta.rc
 variable file:  tprism/halfcubocta.dat
    digit list:  src/mm.dls

CONTACT:

Bob Burkhardt
Tensegrity Solutions
Box 426164
Cambridge, MA 02142-0021
USA

e-mail: bobwb@juno.com

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