From: =?Windows-1252?Q?Rapha=EBl_Guinamard?= 
To: "ATM" ,
        "Roy Diffrient" 
Reply-To: =?Windows-1252?Q?Rapha‰l_Guinamard?= 


Roy wrote
> >
> > First, forget about bending.  Truss stiffness does not result from
> > resistance to bending
.
.
> > Have you read about Hooke's Law? It says that the change in length of an
elastic
> > material (such as a metal shape) in tension or compression is calculated
> by
> > the equation P L / (A E),
> > Those changes in length are sufficient to directly cause truss
deflection

Roy,
If I understand correctly, this means that all the fantastic work done by
Tom is only one part of the problem... I suppose that Grape is not able to
calculate the effect of Hooke's law? (is it true Tom?)
Do you know if another sofware is able to calculate this effect? Could we
simply add the change of position you mentioned here
http://astro.umsystem.edu/atm/ARCHIVES/APR00/msg00921.html to the
deflection of grape
http://overton.tamu.edu/aset/krajci/truss-analysis/truss-analysis.htm to
have a more accurate result ?

Rapha‰l Guinamard

--- BBBS/NT v4.00 MP