Hello all,

I'm trying to do a static simulation on what I see as a simple setup. I have basically four plates meshed as bodies in a stack; plate 1 bolted to plate 2, plate 2 to 3, 3 to 4. Plate 1 is treated as rigid, and I fix one face of it. I apply some forces to plate 4, which I also treat as rigid. I want to see where stresses are occuring in plates 2 and 3. I am using bolt connectors to simulate the bolted connections and I have a global No Penetration contact. I have set the friction coefficient in the Study Properties to 0.6. The solver is telling me my model is unstable.

I'm assuming I'm missing something simple. I have rigid geometry fixed in space, then only bolt connectors holding plates together; I was under the impression that the bolt connector would account for the pressing force of the bolts causing friction between the plates and I know the friction between plates is much much higher then the forces I have specified in the study.

My bolt connectors are made using the edge of one hole, then I select the clearance bore and the threaded bore - Maybe because they are not "tight fit", there is slip allowed between the clearance hole diam. and the "bolt cylinder"?

Using soft springs did not help.

Anyone have an idea what is destabilizing the model?