I am trying to simulate a press fit plastic retaining ring in Solidworks Simulation using a Nonlinear study. I am using the 2d axisymmetric simplification.
For boundary conditions, all edges of items 1 2 and 3 are constrained such that the parts are essentially rigid. Body #2 is completely fixed. Body #3 is fixed in the horizontal direction and a downward displacement is applied from time = 0 to time = .5 so that it contacts Body #2. Body #1 is fixed in the horizontal direction and an upward displacement is applied from time = .5 to time = 1 so the that it also contacts Body #3. Body #4 is the press fit ring of interest. I am using no penetration contact sets with no friction.
The press fit ring is made of UHMWPE. A representative true stress/strain curve is shown here:
To try and simplify the material model, I have been using a bilinear plasticity simplification. Ex = 850 MPa and Etan = 104 MPa. Poisson's ratio is 0.46.
For a first run, I ran with a linear elastic model to test out the contact and boundary conditions. Shown is the stress plot at time = 1. Maximum stress is 122 MPa.
When I run the plastic model, I get failure at Step > 1 with the classic error message referencing a load limit or buckling:
Does anyone have any ideas about what might be going wrong here? It seems like the contact is failing for some reason with the plastic material condition. One thing I have noticed helps the solution get further is to increase my ETan, making the material stiffer after yield, but obviously this doesn't represent the material I will be using.