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.

[pdsamuel]

Hello,

The issue is that ELFORM23 i.e 20 noded hexahedral (solid) element form does not work with MAT318. It gives an error message as ' does not work with ELFORM3". 

Has anyone been able to use the 20 Hex solid with MAT318?

Response from ANSYS (LS-DYNA) will be appreciated!

Thanks!

[Pedram Samadian]

Hi Shahriar,

Sorry for the late reply.  I just saw your comment. Ansys LS-DYNA 2024 and 2025 include the R14 solvers.

Thanks,

Pedram

[Pedram Samadian]

Hi pdsamuel,

This element type is not very commonly used. Are there any specific reasons that you are using ELFORM = 23? However, as per the manual, this material models supports all solid elements, so there shouldn't be any limitation. Please use the latest solvers available on the ftp website (LSDYNA Download / Install Overview). There might have been bugs in the code, which were fixed later on.

Please let me know if you have any questions.

 

Thanks,

Pedram

[pdsamuel]

Hello Pedram,

Unfortunately, even with R15.0.2 (smp_d)-ELFORM 23 does not work with MAT318. 

I get this error:  *** Error 41295 (SOL+1295)
     Material type 318 is not available for solid element type 3

Can you please look into this?

Thanks 

[Pedram Samadian]

Hi pdsamuel,

You are using ELFORM = 23; why is the error message talking about element type 3? Please use double precision MPP solvers instead of SMP ones. MPP codes are much more advanced and well-maintained thaN SMP codes.

We also have R16 solvers available. Please give them a try and let me know how it goes.

Thanks,

Pedram