Hi, I'm new here and I would like help with a problem. I am trying to verify a torsion calculator for round tubing or pipe. However, I am having trouble trying to find a way to use a materials specified yeild strength and or tensile strrength(only info I have other than material type/grade) to find the shear modulus. Also, I'm just trying to find out the max torque that can be applied to a tube/shaft before it shears or deforms in any way. Any help with this problem would be greatly appreciated!
OK, I think I have it, I just need some verification.
If I use the formula:
Torque(max) in LB = [ (max shear stress in psi)(polar second momentof area in inches^4)/R in inches]/12inches
and I use the Von Mises contant/multiplier of 0.577 to convert minimum yield strength to maximum shear stress.
Does this make sense to anyone else?
Last edited by fzr400racer; 03-20-2012 at 10:42 AM. Reason: I have done more research/read other posts
Welcome to the forum.
If you have the elastic modulus and poisson's ratio you should be able to calculate your shear modulus for your material with this:
G = E/(2*(1+v)), where E is the elastic modulus, G is the shear modulus, and v is poissons ratio. For steel v is usually around 0.27 to 0.3, just do a google search for your material and go from there.
0.577*min yield will give the approximate yield stress in torsion, but it could be more or less depending on the material.