Contact non-linear issue

[Salm979]

I have been trying to solve a model, but there is no convergence achieved. The model is attached.

The boundary conditions are as follows, frictionless in two sides of the rectangular object, a displacement constraint in the z direction in the 3rd side (set z to 0), fixed support in the cylinder -applied at the sides-, and a force in the y direction at top of the rectangular object -force is minus-.

There are three regions in which contact occurs. I set two to be frictionless and one to be bonded -down at the bottom-.

I expect the cylinder to move upwards in the y direction and initially it does that! However, when it reaches a certain load it fails due to a rigid body motion -that is what I think anyway-.


I tried almost everything I could think of, changed the contact to frictional, load in steps, gave it more substeps, changed stiffness, ..etc

Any help is appreciated !

 

[Salm979]

By the way this is my second week using ansys only, so I could have missed some simple things!

 

[Salm979]

argh.. boundary conditions !