I'm using Autodesk Simulation Multiphysics 2013 on W7 64 bit.
I'm simulating pressure in a tank. I'm interested in Bending Stress. In Static Stress with Linear Material Model, using plate/shell elements: in the Results/Settings I can find Plate/Shell Options and ask for Bending Strain/Stress. It's OK. But due to Large displacement, I need to use MES simulation. I can find the same options for Plate/Shell options. But the Bending/Membrane options are greyed out and I can't change from Total Stress/Strain to Bending Stress/Strain. Do I do something wrong? Is there any reason this option is greyed out? Is there an other method to obtain wanted results.
The reason that the bending stress/strain option is disabled in MES is because MES does not calculate the bending and membrane stresses separately. Or maybe it does not output them separately. I am not sure which is correct since it is buried in the processor. But I suspect the processor actually calculates the stress at N points through the thickness of the shell and outputs the top and bottom surface stress.
If the shell is truly experiencing pure bending and axial stress, then you could estimate the bending and axial stress from the following two equations, two unknowns:
- stress on top = axial stress + bending stress
- stress on bottom = axial stress - bending stress
The signs of the axial and bending stress should indicate whether the shell is in tension (+) or compression (-) and whether bending "up" or "down" (probably following a right-hand rule, but I do not know the details).
16 years experience with Simulation Mechanical