hello @ialina , i am not well aware of SSR keyword, but why don't you apply some constraints to your model like remote displacement or use spc to free rotation by an axis and axis component, you are asking the solver to rotate but when you give no constraints, it simply don’t understand, And your hourglass is more evident try to correct them. Why are you using motor type, why cant be Surf to surf with some set friction any specific reasons?https://forum.ansys.com/discussion/comment/108382#Comment_108382

Dear @ramgopisetti, ,nthank you for the hints. I am applying the mortar type as it is the preferred method for implicit analysis (at least i read so in the manuals). The keyword *BOUNDARY_SPC_SET restricts the nodes on the inner side of the disk. I understood the concept of the *LOAD_SSR so, that the body does not rotate, it is analysed in a static manner with respect to the arbitrary reference configuration. So, i assumed, nodes should be restricted. I cannot prescribe displacements as i need them coming into normal contact with the flat rectangular body. I could definitely try to move the disk towards the surface, true. And then, apply a translational displacement to it. However, according to the article I read, ni need to work with velocities, not displacements.nPlease, let me know if you have any other ideas in mind.nRegardsn