Learning Forum

[Jérôme RENAULT]

According to LS-DYNA Material Manual, *MAT_058 can be fed with stress strain curves for tensile/compression and in-plane shear. Is there a way to include these curves directly in the engineering data in Workbench without the need of modifying the LS-DYNA input files generated by Mechanical/LS-DYNA to include it before analysis ?

Regards,

[Reno Genest]

Hello,

I don't think it is possible in engineering data. You can define *MAT_058 in engineering data:

But, if you define negative values for Ea, Eb, and Ec for example, Workbench will expect real values and will apply the units to it so that in the input.k file, -1 becomes -1E-6, -2 becomes -2E-6, and -3 becomes -3E-6. And so it does not work.

The best way to do this would be to use a command snippet in Mechanical and define the *MAT_058 card this way:

 

The negative value for Ea, Eb, and Ec correspond to a load curve for the stress vs strain. You can define the load curves (*DEFINE_CURVE) using a command snippet at the environment level:

 

 

Let me know if this helps or not.

 

Reno.

[Jérôme RENAULT]

Hello Reno,

First of all, many thanks for your answer. It helps for sure (also concerning the way to manage LS-DYNA Keywords snippets).

By the way, it seems to be not as important as expected at the beginning of the analyses we are working on. What I mean is that the inclusion of nonlinear behavior and the damage were not understood as it was supposed to be. We are going to work with constant value first for the different modules and then if needed we will add nonlinear module thanks to the definition of dedicated curves by applying the process you described in your answer.

Nevertheless, I hope that this kind of feature will be integrated in the next releases of Ansys (I mean at the "Engineering Data" level) as it allow us to lock and so on protect the material data in our models.

 

Best regards,

 

Jérôme

[Reno Genest]

Hello Jérôme,

I will file an enhancement request for this; it will help in the case where the composite layup is built with Ansys Composite PrePost (ACP).

 

Have a great day!

 

Reno.

[Reno Genest]

Hello Jérôme,

I filed an enhancement request to add this feature. It won't be in the next release (2024R1) because this release is already frozen. But, it might be in the releases after depending on priorities.

 

Have a great day!

 

Reno.