Reno Genest
Ansys Employee

Hello,

There are many ways to include failure. Many material models (*MAT_015 included) have material failure built-in. For metal failure, plastic strain at failure is commonly used. In *MAT_015, you can have failure strain a function of triaxiality (state of stress), strain rate, and temperature using the D parameters.

 

You don't need to have such a complex failure to begin with. *MAT_024 is commonly used to model metals and you can define a simple plastic strain at failure using the FAIL parameter. Once you get it working, you can add complexities (triaxiality, strain rate, or temperature effects) to be more accurate in your failure prediction. Here is a good video on *MAT_024:

https://www.dynamore.de/de/download/presentation/2020/copy_of_dynamore-express-good-old-mat_024-a-review-of-ls-dyna2019s-most-popular-material-model

 

Also, you will find some examples of material models (*MAT_224; tabulated Johnson-Cook) for some metals used in the aerospace industry on the Aerospace Working Group:

https://awg.lstc.com/tiki-index.php?page=Material+Parameter+Sets

You will find the LS-DYNA parameters (.k file) and also reports on how they developed the material model. This is very instructive.

At last, you could use *MAT_ADD_EROSION or *MAT_ADD_DAMAGE_GISSMO to add failure to your model. In the end, you want to be able to reproduce experimental test data. If you are able to achieve it, then your model should be ok. 

 

Let me know if this helps or not.

 

Reno.