Make your own free website on Tripod.com

Twelve-Stage Tensegrity Torus Datasheet


Copyright © 2005 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.

# struts

<Member> s13  p1A  p3B   -1.0  sqr(2.2)  1 Con CalcClear *
<Member> s35  p3A  p5B   -1.0  sqr(2.4)  1 Con CalcClear *
<Member> s51  p5A  p1B   -1.0  sqr(2.2)  1 Con CalcClear *
<Member> s24  p2B  p4A+  -1.0  sqr(2.4)  1 Con CalcClear *
<Member> s46  p4B  p6A+  -1.0  sqr(2.4)  1 Con CalcClear *
<Member> s62  p6B  p2A+  -1.0  sqr(2.2)  1 Con CalcClear *

# tendons

<Member> t12A p1A  p2A   1.00 1       3 Con *
<Member> t23A p2A  p3A   1.00 1       3 Con *
<Member> t34A p3A  p4A   1.00 1       3 Con *
<Member> t45A p4A  p5A   1.00 1       3 Con *
<Member> t56A p5A  p6A   1.00 1       3 Con *
<Member> t61A p6A  p1A   1.00 1       3 Con *

<Member> t12B p1B  p2B   1.00 1       3 Con *
<Member> t23B p2B  p3B   1.00 1       3 Con *
<Member> t34B p3B  p4B   1.00 1       3 Con *
<Member> t45B p4B  p5B   1.00 1       3 Con *
<Member> t56B p5B  p6B   1.00 1       3 Con *
<Member> t61B p6B  p1B   1.00 1       3 Con *

<Member> t1AB p1A  p1B   1.00 sqr(1.0) 2 Con *
<Member> t3AB p3A  p3B   1.00 sqr(1.8) 2 Con *
<Member> t5AB p5A  p5B   1.00 sqr(1.8) 2 Con *
<Member> t2BA p2B  p2A+  1.00 sqr(1.3) 2 Con *
<Member> t4BA p4B  p4A+  1.00 sqr(2.1) 2 Obj *
<Member> t6BA p6B  p6A+  1.00 sqr(1.3) 2 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.
        The values are in model units.

      s13:          2.2       s35:          2.4       s51:          2.2
      s24:          2.4       s46:          2.4       s62:          2.2
     t12A:            1      t23A:            1      t34A:            1
     t45A:            1      t56A:            1      t61A:            1
     t12B:            1      t23B:            1      t34B:            1
     t45B:            1      t56B:            1      t61B:            1
     t1AB:            1      t3AB:          1.8      t5AB:          1.8
     t2BA:          1.3      t4BA:      2.00111      t6BA:          1.3


        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.

      s13:     -4.54304       s35:     -3.04858       s51:     -4.54304
      s24:      -3.6661       s46:      -3.6661       s62:     -5.58341
     t12A:      4.61372      t23A:      1.83869      t34A:      2.97757
     t45A:      1.40255      t56A:      3.58335      t61A:      2.40645
     t12B:      2.40645      t23B:      3.58335      t34B:      1.40255
     t45B:      2.97757      t56B:      1.83869      t61B:      4.61372
     t1AB:      3.65567      t3AB:      2.15891      t5AB:      2.15891
     t2BA:      3.11919      t4BA:      2.00111      t6BA:      3.11919

        Average tendon force magnitude: 2.76987


        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> 238/2.4
        Strut and Tendon Hub Adjustments - s;t> 4 3.5
        (The 4 mm adjustment for the strut is the amount
         the screw-eye center extends from the dowel.  The 3.5 mm
	 adjustment for the tendon is half the outer diameter of the
         screw eye.)

 
      s13: 210 0       s35: 230 0       s51: 210 0       s24: 230 0
      s46: 230 0       s62: 210 0      t12A:  89 0      t23A:  91 0
     t34A:  90 0      t45A:  91 0      t56A:  90 0      t61A:  90 1
     t12B:  90 1      t23B:  90 0      t34B:  91 0      t45B:  90 0
     t56B:  91 0      t61B:  89 0      t1AB:  90 0      t3AB: 169 0
     t5AB: 169 0      t2BA: 119 0      t4BA: 188 1      t6BA: 119 0

ray trace of tensegrity torus
Oblique View of the Twelve-Stage Tensegrity Torus
with Point Labels
(VRML Model)

structure file:  torus/x3l12torusa2.rc
 variable file:  torus/x3l12torusa2.dat
    digit list:  src/mm.dls

CONTACT:

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

e-mail: bobwb@juno.com

Back to First Tensegrity Tower

More Datasheets