SaiD
Ansys Employee

Hello,

Could you share the Force Convergence plots (you can obtain them by going to Solution Information > Force Convergence in the details)? Another place to look at would be the Solution Information > Solver Output and search for any error or warning messages. The messages might provide some clue about what is causing the non-convergence.

Bonded contact is a linear contact (meaning that the status of the contact remains unchanged throughout the simulation) and that is probably why the solver is able to solve it without any convergence issues. You should expect a very large large force reaction when using bonded contact (as you are seeing) since this simulates the case of no separation and no relative sliding of the screw wrt the vertebrae.

Ansys employees are not allowed to download any attachments from the forum, but you can trying attaching an archived file without the results (so that the file size is smaller), in case someone else has some suggestions. To reach a wider audience, please add inline images to explain your model setup etc.