Reply To: LS0DYNA High Strain Rate issue using Yeoh Model

[Jim Day]

If you're using an under-integrated element formulation, like solid formulation 1 (ELFORM=1), hourglass control is on by default. You have to use *CONTROL_ENERGY to turn on the hourglass energy computation.
If your nodal velocities in the high strain rate case far exceed the sound speed of the material, that would explain the need to reduce the time step scale factor.
At extremely high velocities, solid materials behave more like fluids. It's just physics. See my earlier comment about inertial effects dominating the response.