I got a problem when simulating a process of compressing a piece of metal with a punch. As you can see in the figures, I applied a pressure on the upper punch, set fix constraint on the lower punch, the boundary condition for the sample/upper punch surface is mechanical contact, and the lower boundary of the sample is set to roller constraint.
Then I got a Mises stress on the contact surface to be very wavy, I wonder how to remove those waviness?
Best,
Yun Deng