Learning Forum

[shahria]

Hello,

I am trying to set up an explicit dynamic simulation with the TNM material model. According to the Ls dyna keyword manual , volume 2 ( dev), this material model supports ELFORM 3, which, to the best of my knowledge, refers to 20 node hexahedral elements. However, when I run the .k file containing 20 node hexahedral element model in Ls Dyna R14 I get the following error : “Material type 318 is not available for solid element type 3". I previously tried 8 node and 27 node hexahedral elements but received the same error. 

Besides, I tried to assign the TNM model to the geometric part overwriting the default structural steel in Workbench Ls Dyna using the command snippet option. I am able to run the simulation without any error in this case but from analysis of the result it appears that the solver is not considering the TNM parameters I have assigned. 

I am not sure what I am missing here. Can anybody please point out the right way to implementing the TNM_Polymer model with Ls dyna? I would highly appreciate any suggestions or insights in this regard. 

Thanks in advance.

Shahriar.

 

 

[Pedram Samadian]

Hi Shahriar,

The LS-DYNA User’s Manual Vol. II (LSDYNA Manuals) indicates that this material card supports thick shell element types of 3, 5, and 7 and solid elements. Those specified elements types refer to the thick shell elements, not the solid elements. 

You are right that Solid Element Type 3 is not supported by this material card as I also got a similar error message using different solver versions. I tried other solid element types, and they worked properly with this material card. Are there any specific reasons you want to use Solid Element Type 3 for your model?

Thanks,

Pedram

[shahria]

Hi Pedram,

 

Thank you for clearing up my confusion. It means a lot. I badly misunderstood the documentation and thought that TNM model only supports solid elements ELFORM 3, 5, 7. I previously tried ELFORM 4, and it didn't work, which added to my misunderstanding. After your response, I tried different solid elements and found that the model works for several other ELFORMS, as you said. I moved forward with ELFORM 10 and my model result also matches well with the experimental data. 

I have one last query: What versions of Ansys come with Ls Dyna R14? Or the Ls Dyna version is not related to the Ansys version a particular client has access to? I am asking this because my end goal is to run batch simulations with a particular HPC cluster. I am wondering what type of Ansys license they should have so that I can run my MAT_TNM_Polymer based Ls Dyna model.

 

Regards,

Shahriar.