March 6, 2024 at 7:48 am
hdonner
Subscriber

Hi Marcin, 

in case of pressure loads in combination with large deflection, the stiffness matrix becomes unsymmetric. Thus, please go to Analysis Settings -> Nonlinear Controls -> Newton Raphson Option = Unsymmetric. 

Further, if this stability issue appears, which is mentioned by Dave, I would activate quasi-static solution in the Analysis settings. Please take care that the material has a density. Last but not least, I would set the max. number of substeps to 1e9, allowing Ansys using very small time steps.

Were these hints successful?

Kind regards

Hendrik