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Dear Community, I am trying to implement an UEL for implicit dynamics analysis. After applying time-stepping scheme (implicit backward Euler), the formula of RHS vector requires the value of solution variables at time t. However, in UEL only an estimate of solution variables and their...

Thanks for your comments guys. My problem is solved now.

Thanks for your comment. Why doesn't first one match with the def of strain rate? In the manual, 'stepTime' is Value of time since the step began. It also represents the length of time corresponding to the current strainInc.

Dear community, I need to implement strain rate effect through VUMAT and I need to calculate strain rate in my VUMAT code. I read the VUMAT documentation and found two time-related variables: stepTime and dt. It seems that both variables can be used for the aim. T think that the strain rate can...

Thanks for your comment. I have tried mat059 with shell elements and it worked. So the conclusion is that it can only work with shell elements, not tshell.

Does anyone know whether we can use MAT_059 with TSHELL element in ls-dyna? I saw an introduction slide saying that MAT_059 is compatible with shell,tshell and solid elements. However, I have tried both two types of MAT_059 with TSHELL element and the solver always told me that the section type...

Thanks, guys, after trying these methods I finally gave up because they are too complicated for my model. I will use finite thickness or contact cohesive behavior. Thanks again!

Dear Community, I am working on modeling delamination between plies of composite laminate and now I need to create zero-thickness cohesive layer between plies. How can I do it? Currently I am using finite-thickness cohesive layer but the result has a small discrepancy from that of literature...

Make sense. Thank you!

Dear Community, when I use Abaqus UMAT and VUMAT, I notice that in the official doc the calculation is performed at each MATERIAL POINT. I am wondering what MATERIAL POINT is. Is it just identical to integration point? Thx!

Got it. Indeed it doesn't make sense to incorporate that in VUMAT since it defines constitutive relation.

Yes! I have added reference to his repo and thx for mentioning that. Actually, I have already done one element test for my code for orthotropic elastic material. The results had discrepancy too but it's negligible so I didn't pay attention on it. Although Rutger mentions that his VUMAT may not...

A previous question on this forum is cited here, https://www.eng-tips.com/viewthread.cfm?qid=475510#post

Dear Community, Hi! I am trying to verify Abaqus VUMAT with simple examples so I wrote a VUMAT for orthotropic material and compare the result with Abaqus built-in material model (Elastic -> Engineering constants). The material constants are given in 1.png and 2.png. All other settings from...