Fortunately, I could solve my problem. The problem was not choosing appropriate name for one of my variable and a problem in defining my iteration variable.

Hi Ali, 

This error often shows that there is something wrong with your routine. Zero or negative dilatational (bulk) modulus practically means that your material will grow in size under hydrostatic pressure... Are you sure that the one-element results are correct even for complex load histories? Are you perhaps near incompressible material properties?

Regards,

George

Dear Goerge;

Thanks for the reply. I have checked the code for compression and simple shear mode for one element and my run completed to the end. However, I don't know how much reasonable is the answer. 

Hi Ali,

I don't know what your code is doing,  but the best practise is to compare your results with test results if available. If not, use engineering judgement and apply more complicated load histories (e.g. biaxial tension). Also try to "push the code to its limit" where things might get unstable. A failure is helpful for understanding what can be wrong.

Regards,

George

Fortunately, I could solve my problem. The problem was not choosing appropriate name for one of my variable and a problem in defining my iteration variable.

Hi Ali

I met the same problems with you in my vumat. My vumat can support at most 136 element. Could you tell me more details about how you solve this problem?

Best,

JIadi

Hi Ali,

I have same problem, Could you please explain it, how did you solve your problem?

Regards,

Mehdi

I believe this has something to do with your parameters. You have to check the names of your parameters and make sure they are legal names for VUMAT.