Unable to Obtain Non-Uniform Residual Stress Distribution in ISMB 150

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Dear Experts,

I am currently performing a nonlinear analysis of an uncorroded ISMB 150 steel beam using solid elements in ANSYS Mechanical. As part of the study, I am attempting to introduce residual stresses typically present in hot-rolled steel sections.

However, I am facing difficulty in obtaining the expected non-uniform residual stress distribution across the beam cross-section (compressive stresses near flange tips and tensile stresses near the web–flange junction). Despite defining the residual stress input, the results appear to be either uniform or not properly developed in the model.

I would appreciate guidance on the following points:

1. What is the recommended procedure to introduce non-uniform residual stresses in solid element models of hot-rolled steel beams?

2. Should residual stresses be applied using the thermal analogy method (equivalent temperature field) or through initial stress commands (INISTATE)?

3. Are there specific solver settings or modeling precautions required when introducing residual stresses in a nonlinear analysis?

Any suggestions or example approaches for modeling residual stresses in ISMB sections would be greatly appreciated.

Thank you for your time and support.

Best regards,
Gopi

 

[dlooman]

Using thermal strain is sometimes used as an artificial way to specify residual stress, but the INISTATE command is the more appropriate method.  It will require some expertise in APDL scripting though.  Initial steps would be to do a search on INISTATE in the APDL doc and to run a simple test on geometry where it is easy to select or specify the elements.