When I said Contact, I should have been more specific and said Frictional Contact. Your model is using Bonded Contact, which doesn't pick up new contact as the structure deforms.nYou will have some trouble with frictional contact because your stack of washers is not precisely assembled. There is significant interference. Fix that before you start.nThere are five waves in each washer. Make two planes, and cut through the washers where they touch, then apply symmetry on those planes and the model that will solve much faster.n