Hi,

I am modelling a compression test (quasi-static) for a micro lattice structure till 60% of strain.

i run through implicit and also explicit but the problem is that I saw overclosure or penetration of top platen into the top surface of lattice at later time step (around 60% of strain). I tied top and bottom platen to lattices and also used self-contact for individual struts.

On the other hand, I know that when I tied the top and bottom platen to the lattices , the initial stiffness is way higher than what I got from experimental test whaich is another problem
I am just wondering if BCs and contact are correct.

Can anyone give me advice how I can sort out the problem (higher stiffness and overclosure) and define the right BCs.

Many thanks for your help on this point.