Two-fold Prism Girdled by Four-fold Prism
with Point Labels
(NB: The colors are reversed here as compared with the assembled model.)
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> sa pa' pa -1.00 0.0 1 Obj CalcClear Inelastic *
<Member> sb pb' pb -1.00 0.0 1 Obj CalcClear Inelastic *
<Member> s1 p1' p2 -1.01998 0.0 9 Obj CalcClear Inelastic *
<Member> s2 p2' p3 -1.01998 0.0 9 Obj CalcClear Inelastic *
<Member> s3 p3' p4 -1.01998 0.0 9 Obj CalcClear Inelastic *
<Member> s4 p4' p1 -1.01998 0.0 9 Obj CalcClear Inelastic *
# tendons
<Member> tab' pa' pb' 3.0 sqr(1.0) 2 Con *
<Member> ta1' pa' p1' 3.0 sqr(1.0) 2 Con *
<Member> ta2' pa' p2' 3.0 sqr(1.0) 2 Con *
<Member> tb3' pb' p3' 3.0 sqr(1.0) 2 Con *
<Member> tb4' pb' p4' 3.0 sqr(1.0) 2 Con *
<Member> t1 p1' p1 3.0 sqr(1.0) 2 Con *
<Member> t2 p2' p2 3.0 sqr(1.0) 2 Con *
<Member> t3 p3' p3 3.0 sqr(1.0) 2 Con *
<Member> t4 p4' p4 3.0 sqr(1.0) 2 Con *
<Member> ta1 pa p1 3.0 sqr(1.0) 2 Con *
<Member> tb2 pb p2 3.0 sqr(1.0) 2 Con *
<Member> tb3 pb p3 3.0 sqr(1.0) 2 Con *
<Member> ta4 pa p4 3.0 sqr(1.0) 2 Con *
<Member> tab pa pb 3.0 sqr(1.0) 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.
These values are in model units.
sa: 2.08845 sb: 2.08845 s1: 2.08846
s2: 2.08846 s3: 2.08846 s4: 2.08846
tab': 1 ta1': 1 ta2': 1
tb3': 1 tb4': 1 t1: 1
t2: 1 t3: 1 t4: 1
ta1: 1 tb2: 1 tb3: 1
ta4: 1 tab: 1
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.
sa: -2.08845 sb: -2.08845 s1: -2.13019
s2: -2.13019 s3: -2.13019 s4: -2.13019
tab': 1.71887 ta1': 2.01762 ta2': 1.52751
tb3': 2.01762 tb4': 1.52751 t1: 1.96191
t2: 2.48823 t3: 1.96191 t4: 2.48823
ta1: 2.01762 tb2: 1.52751 tb3: 2.01762
ta4: 1.52751 tab: 1.71887
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.
Braided nylon fishing line was used for the tendons.
Prestress forces are assumed to affect tendon lengths and
not strut lengths.
Elongation of Tendon of Unit Cross Section
Under Force of Average Magnitude (fraction)> 0.02
Length Scale Factor> 292/2.08846
Strut and Tendon Hub Adjustments - s;t> 5.0 3.5
(The 5.0 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.)
sa: 282 0 sb: 282 0 s1: 282 0 s2: 282 0
s3: 282 0 s4: 282 0 tab': 130 1 ta1': 130 0
ta2': 130 1 tb3': 130 0 tb4': 130 1 t1: 130 0
t2: 129 1 t3: 130 0 t4: 129 1 ta1: 130 0
tb2: 130 1 tb3: 130 0 ta4: 130 1 tab: 130 1
Two-fold Prism Girdled by Four-fold Prism
with Point Labels
(NB: The colors are reversed here as compared with the assembled model.)
structure file: tprism/x2girdle4.rc variable file: tprism/x2girdle4.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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