I am trying to perform an analysis on a frame that has a ring on the bottom. The ring rests on a set of shafts. Whenever I run the analysis, I get an error stating that the model is unstable. I think it is because of this connection. I have placed a fixed constraint on the ring itself and it solves. I tried to run the FEA with the shafts as part of the assembly with Bonded connections, then I tried with the No Penetration connections. I finally tried to simulate the connection by creating circular split lines where the shafts would be and restraining the areas defined by the split lines allowing them to slide along the surfaces simulating the interaction with the shafts. However this also did not solve. Does anyone have and ideas about how fix the ring to shaft connection and/or simulate it? Thanks.