Looking for Assistance

[jameel ahmed]

Hello All, 

I am modeling quasi-static indentation of a polymeric foam using the explicit solver in LS-DYNA. The indenter is rigid, and the foam is modeled using the MAT 57 material model. I applied a uniform pressure on the indenter to drive indentation and tracked nodal Y-displacement beneath the indenter. The displacement history shows a monotonic trend with small oscillations, indicating dynamic effects. My questions are:

(i) Is pressure-controlled loading appropriate for quasi-static foam indentation in an explicit framework, or is displacement-controlled loading preferred?
(ii) If I prescribe indenter displacement instead, can the explicit solver still be considered quasi-static provided kinetic energy remains small compared to internal energy?
(iii) What best practices (loading rate, damping, energy checks) are recommended when using explicit methods for foam indentation problems?

I would appreciate your time and attention. 

Thanks, 

Best regards,

Jameel