I need to modify existing Johnson-Cook model in LS DYNA to make it work for the material I am simulating. I believe there is must be some source to obtain user subroutine for the JC model rather than writing it from scratch? Please can anyone help me in this regard.
Hi @venkateshmd
So to clarify, you want to modify the Johnson-Cook material model itself, not just the parameters within the model? Unfortunately, I don't have experience writing material models from scratch, nor do I know where you can find the Johnson-Cook code.
May I ask why you want to modify it?
What I mean by modifying is to add more parameters to the existing JC model. Flow stress in the original JC model and modified formulation which I want are shown in the attached figure file. I want to add two more constants D and k. To do this, I need the user subroutine file for the original formulation. Using this, I can edit the code and implement it in LS DYNA. Making the code from the scratch is a big task. I hope you got my point. Generally I have seen that codes are available for Abaqus but not for LS DYNA. I was able to get JC code for Abaqus. But user subroutines writing style is quite different in both these softwares. Correct me if I am wrong.
The reason I want to modify the JC model is that at strain rates above 1000/s, it is not able to predict flow stresses accurately. When a power law is added to it like the one I am trying to do, it works perfectly.
Thanks.
@venkateshmd I'm following up with old topics and this seemed like something that others would find useful. I apologize for not following up with you sooner. Did you figure out a solution to this?