Hello, 

I am trying to simulate a transient thermomechanical model of a roller test rig to get heat generation and stress analysis caused by load, slip and friction coefficient. Model consists of 2 rollers- Hollow Roller and Counter Roller. Load is applied to Counter Roller. I have made 3 steps- loading of counter roller, acceleration of both rollers to their respective velocities and steady running of both rollers. I am using Coupled Temp-Displacement as step. All the material properties are elastic. Nlgeom is on in every step.

However everytime I try to simulate my model I get a warning of NUMERICAL SINGULARITY WHEN PROCESSING NODE with node's DOF in Z-direction, and it leads to an error TOO MANY ATTEMPTS MADE FOR THIS INCREMENT.

All the interaction, interaction properties, constraints, boundary conditions and loads are correctly defined. I have tried various different parameters in step size and increments. I have tried very small step sizes, mesh sizes. But every time while simulating i get this error in the loading step.

I have attached my model's screenshot. Smaller roller is Counter roller and larger one is hollow roller.