Hello all,

I have developed a vumat routine which normally works fine. Its an elastoplastic model that at each step checks to see if stress state is located within the yield surface or not. If its not the routine returns the stress state to the yield surface according to normality. Obviously for the routine to be able to return the stress state back to the yield surface the time increment should be small enough so that the change in stress increment wouldnt be large. In abaqus explicit the program decides about the time step and chooses small time increment to satisfy the stability. However I tested my routine and I realized when the deflection is high at some point the stress increment will be large and thereafter the routine cannot return the stress state back to the yield surface. I thought if I was able to use a time increment less than what abaqus decides then I can solve this problem. Is there any way in abaqus explicit to decrease the time increment of steps? Has anyone ever faced such problem in their routine? I really appreciate any comment or suggestion. And by the way I use both ALE adaprive meshing and nonlinear geometry.

Thanks