Shabnam, I'm not sure I understand your question. The Prony series, for instance a Maxwell model simulating stress relaxation, can be expressed ...

Thanks Fred. Glad you got it working. I usually run my rubber simulations with distortion control, reduced integration, linear element, and hourglassi...

Fred, Did you test your subroutine in planar tension and equibiaxial loading modes? If not, I would check those modes before moving on to simple she...

@castello , Yes, the paper was recently published and is available here: METHOD TO GENERATE ACCURATE ELASTIC AND HYPERELASTIC UNIAXIAL TENSION STR...

My browser is not working well. Has anybody answered yet? Your deviatoric parameters do look problematic. I also doubt you need 3 coefficients to mo...

You can find an updated VUMAT posted on this website here: I can share a paper with you that discusses VUMAT implementation in Abaqus. Search "Travi...

I see. Glad you found an approach that may work for your study. I recently ran into a similar issue. I collected stress relaxation data, but the tim...

stewie6514, I think you have answered your own question. The Prony series is quite limited because it assumes that, for instance, stiffness monotoni...

I-Cabeza, I have not used the functionality in a while, but if I recall correctly, normalizing your relaxation data the way you have done is fine fo...

trcc20, I regularly stop simulations using the first method you describe above. From what you've written, it appears you are aware that you can open...

@fat32ntfs, I have not personally tried matrix multiplication in my codes, but I have some that do (for example, search "Shawn Chester New Jersey In...

@fat32ntfs, Yes, it looks like zero is not defined. I never encountered problems validating this version of the code, so my compiler must have been ...

Great, thank you Jorgen. If you (or anybody else) gets around to a test-drive, let me know if you have any questions. At some stage, hopefully this ye...

Are you still working on this? What differential pressure must you seal? What is driving you to a foam instead of a typical rubber seal?