During running MES with Nonlinear Material Model (drop test) using Autodesk Simulation Multiphysics 2012, this " **Time step reduction due to: Contact penetration " appear in Analysis Information. Can anyone point out the problem ?! why did it reduce time step. Please help me.
At the end of a step/sub-step, if a penetration larger than tolerance is found, software will cut off the step size and re-do analysis for the current time till penetration is small enough.
If this response answers your concern, please mark it as "solved".
In MES surface to surface contact, beside the equilibrium convergence checking, there is contact checking. Even for a step, the equilibrium is convergent, marked with "c" or "cr" in log file. Further contact checking might find big penetration. In this case, Autodesk Simulation will cut time step to obtain a better solution in a smaller step.
For a convergent step, there are some other reasonss beside contact checking, which will result in time reduction,
element Jacobian error in shape function, element Jacobian error in stress calcualtion, creep calculation,
numerical checking in Mooney-Rivlin model, shell element calculation, etc.