Hello everyone,

I am trying to run a quasi-static simulation crushing a tube between two flat, rigid plates. One plate is standing still, the other displacement driven (7 mm in 0.1 s). I would have expected that it still counts as quasi-static and the kinetic energy is much lower than internal energy, but that is not the case, see attached plots.

I uploaded a course version of my model as reference. the original mesh is finer.

Has anyone a clue what I am doing wrong?

I also tried to run the same simulation with implicit solver and 7 mm in 10 s as displacement. It took me a while until the simulation finished without error, but the results are just "different", and i cant tell which is more wrong or right. However, in implicit the energy ratio drops just after start of the simulation from 1 to 0, which I do not understand as well. A clue here would be much appreciated aswell.

Kind regards,

Richard

If you internal energy is zero then there's something wrong with you model setup. My theory is that your units are messed up. What unit system are you using? I know you mentioned mm and seconds but not sure if you mass is g or ton

Hi NegativeVolume,

I hope i did not mess up the unit system. I was using ton/mm/s/N/MPa.

I am simulating a compresible foam material that is encased with steel. The test setup is e.g. radial/axial compression or 3p Bending. Always the kinematic energy is very large. I tried implicit analysis, but not sure if that makes sense.

My steel case (hill 3R mat 122) has RO=7.8E-9 (t/mm^3) E=1.6E5 (MPa), PR=0.3, R00=0.77, R45=0.62, R90=0.60.

The hardening curve is like this (in MPa):

The foam (mat 063) has RO=2.5E-9 (t/mm^3), E=500 (MPa), PR=0.01, TSC = 10 MPa.

The hardening curve is like this (in MPa):

Any ideas what i am doing wrong?