Non-linear analysis of an inflatable air-beam model not converging.
I am analyzing an inflatable air-beam with a baffle (similar to the ones used for inflatable wings).
Both bodies are modeled as surface bodes and meshed by shell-181 elements.
The boundary conditions are - Fixed support at 1 end, force over the cylindrical surface and internal pressure, to simulate the beam.
Shortly after 27-28 converged sub-steps, the solution fails and I get an error stating - "Solution not converged at time 5.47E-02 (load step 1 substep 30). Run terminated."
Also, the Newton-Raphson residual plots show barely any residuals -
Things I have tried -
1. Refining the mesh.
2. Increasing number of steps and sub-steps.
3. Adjusting % tolerance and MINREF load conditions.
4. Changing the material.
When I changed the material to structural steel the analysis did converge but I cannot converge it at all with the required nylon fabric material. I even tried reducing the overall load to about 1-2 N but that didn't help.
Are there some irregularities in my material properties or am I missing something else?
Thanks in advance