Thanks for the feedback. The expansion of shells to solids being non-linear in combination with NLGEOM= True is understood to be the root cause for the convergence issue.
If I understand correctly, this means thats shell structures with NLGEOM= True currently need to be simulated with solid elements in CCX to avoid the convergence issue which has drawbacks regarding computational efficiency.
Is it planned to introduce different Shell Elements in CCX that work with NLGEOM = True or are there significant difficulties expected to change the Source Code accordingly?
Thanks!