Datasheet for Emmerich's Prism

```        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
struta  po2' pi1  -1.0      0.0      1 Obj CalcClear *
strutb  pi1' po2  -1.0      0.0      1 Obj CalcClear *

# interlayer tendons
xlta    pi1' po1   0.0      1.0      3 Con CalcClear *
xltb    pi1  po1'  0.0      1.0      3 Con CalcClear *

# end tendons
end     pi2  pi1   0.0      1.0      2 Con CalcClear *
end'    pi2' pi1'  0.0      1.0      4 Con CalcClear *
endx    po1  pi2   0.0      1.0      2 Con CalcClear *
endx'   po3' pi1'  0.0      1.0      4 Con CalcClear *

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.

struta:      1.73205    strutb:      1.73205      xlta:            1
xltb:            1       end:            1      end':            1
endx:            1     endx':            1

Relative Member 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.

struta:     -1.73205    strutb:     -1.73205      xlta:            1
xltb:            1       end:            1      end':            1
endx:            1     endx':            1

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> 170/1.73205
Strut and Tendon Hub Adjustments - s;t> 6.0 3.5
(The 6.0 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.)

struta: 158 0    strutb: 158 0      xlta:  89 1      xltb:  89 1
end:  89 1      end':  89 1      endx:  89 1     endx':  89 1

```

View of Emmerich's Prism with Point Labels

 ```structure file: tprism/x3eprism2.rc variable file: tprism/x3eprism2.dat digit list: src/mm.dls ```

CONTACT:

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

e-mail: bobwb@juno.com