Learning Forum

[anarberk]

Hello everyone, I'm new in the forum and Ls-Dyna. I'm trying to simulate a gun system that consists of cartidge, ammunition, barrel and the hydraullic fluid. I've defined the fluid in Engineering Data. When I've tried to run the simulation so many times after tries the ways that I'd found some solutions in the internet to solve the problem, I've got always "termination due to the mass increase error". Could you help me about the problem? I've attached some screenshots(2022 R2). I've also read; https://www.dynasupport.com/howtos/material/negative-volume-in-soft-materials

1-Tried to things that I don't know clearly;

2-Fluid data;

3-Mesh;

4-Settings;

5-İnfo;

[Dennis Chen]

 

anarberk, the way you added the command snippit to add the ls-dyna mat/section/contact is not how you do this inside workbench ls-dyna.  I don’t have a very short video explaining how this is done but i just made a tutorial video for a hail-strike analysis where I used the same command snippit to define mat,eos,contact like you wanted to do, maybe you can quickly scan through below video and see if it helps you.

https://www.youtube.com/watch?v=SJVvZiCq-Hk

there are also likely numerous other issues with this model.    I would recommend maybe starting with a less complicated model or dissect your current problem into serveral smaller models and then focusing on one part at a time.   For example, you could focus on how to properly define fluids in the lagrangian frame by building a simple example model (see mat_null).    

Best of Luck.

[Rob]

Duplicate  https://innovationspace.ansys.com/forum/forums/topic/ls-dyna-negative-volume-problem-2/ so closing.