VUMAT Viscoelasticity Problem

Hi all,

I’m trying to model agglomerate coark behaviour with a VUMAT in Abaqus/Explicit. In the VUMAT I use the Ogden Hyperfoam model to describe the hyperelastic behaviour and for the viscoelasticity I use the Prony series model (generalized maxwell). Lastly I include damage with Mullins effect. I have validated the model with compression tests at various strain rate but I have problems with a puncture test because the velocity profile does’t fit with the experimental one.

How can I solve this problem?

Thanks a lot!