I am trying to model a hollow beam that failed in punching. I tried to even reduce the loading plate to very small dimensions to force the model to fail in punching, but still in vain. Is there any certain procedure I should follow to have the punching mode of failure. The load deflection curve reaches an ultimate then softening without any drop. Also, the number of iterations reach the maximum I set for it. Should I expect a drop in the load deflection curve or no?

Thanks in advance