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USERMAT for progressive failure analysis


masoudm
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Hi sir,

I am writing USERMAT subroutine in ANSYS for progressive failure analysis of composites subjected to tension. I am not getting good agreement between numerical and experimental Load vs Displacement curve. I am not able to rectify my mistake. Can you check it if i have made any mistake? I am attaching my USERMAT subroutine here in zipfile.

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Jorgen
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Hello Brijesh,

If you dont get good agreement between experimental and model predictions that may mean that your model theory is not appropriate for the material that you are studying. Are you sure your selected model is appropriate in this case?

-Jorgen

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masoudm
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(@masoudm)
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Dear sir,

Thank you very much for reply. With the same concept one of my senior performed progressive damage analysis. I am using usermat but he hasnt used usermat. He has used macros and he has degraded properties of whole element on failure initiation. I am also getting convergence issues with the usermat. what should be done to avoid it?

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Jorgen
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I am afraid that if you get convergence properties then that is likely caused by either the FE setup, or the USERMAT implementation. I recommend that you validate your USERMAT code by running simple FE simulations first. Once you are confident that it works you can try your real model.

-Jorgen

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masoudm
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I am using sudden degradation of material properties for CFRP laminate. I have attached my usermat code in first post. If you have time, can you check it once? And i have verified that my code is running fine for one element. What solution options i.e. number of substeps, convergence tolerance should be used for progressive damage?

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