Ansys Employee
What is the yield stress value defined in engineering data? Could you check the equivalent stress result and see if stress in any region exceeds this value? Also, instead of fixing the ends scope a remote displacement to the circular edges (surface splits), free translation rotation in Z and fix rest. The mesh quality can also be improved to an all quad mesh. And I hope you have set Large deflection under analysis settings to "on".
Regards Ishan.