# Simple torque analysis doesn't match hand calcs?

Question asked by Aaron Hayden on Dec 12, 2008
Latest reply on Dec 15, 2008 by Bill McEachern
Folks,

I have a tube loaded in a static torsion condition. The tube is 1" O.D. by .67" I.D. by 36" long. The tube is fixed at one end and the load applied to the other. First I calculated the Shear Stress by hand based on T = S X Z (where T is the torque applied and Z is the Polar Section modulus). That works out to about 48,000 psi. Cosmos says 86,000 psi (about 1.75 times). I turned on large displacement, but didn't see any change in results. Clearly I have made a mistake somewhere, but this seems so simple I can't figure out where. I appreciate any input you guys have.

Also, is there a way to get Cosmos to calculate angular displacement for the above torque application? I haven't looked into figuring that part out yet, but since I am here I thought I would ask.

Thanks,
Aaron