I have a simulation which uses mat model 77, an ogden rubber model. It runs fine in lsdyna 970, but after updating to 971, the min timestep becomes much smaller (0.585E-05 goes to 0.429E-07) and I get negative volume elements. Looking at the release notes for 971...
Does LS-DYNA support 20 noded hexahedral elements?
Running the exact same simulation with linear (8 noded bricks) works fine, but after giving the elements midside nodes, the all quadratic bricks essentially are ignored by LS-DYNA even though they exist in the input file (IE the part with the...