3D Thermal Strain, Quick Hand Calc?

[vikiso]

I know the 1D equation...coeff. th. exp. * delta T * L = e. I am able to do a quick check with that equation, but I want to check my FEM results with a more accurate 3D equation. Anyone know of a simplified way of checking strains in 3D?

 

[prex]

If you are speaking about unconstrained thermal expansion, then in 3D every linear dimension of the object will elongate exactly with the formula for linear expansion.
However, as you mention FEM results, I suppose you have stress in your object (otherwise you would get the result with very simple hand calcs): in that case there is no general rule, only a few simple cases may be solved by analysis and you must specify all the conditions (geometry, materials, boundary). prex

http://www.xcalcs.com

Online tools for structural design

 

[davefitz]

I would suggest reviewing some of the books by Timoshenko. If I remember right, for a constrained object in 3 D, the stress one would normally calculate for linear problems is multiplied by the factor ( 1/ poisson ratio ) = (1/0.35)