Why the routine you proposed in the example for rotordynamic prestressed analysis fails?
Hi, I am a student developing computations on rotordynamics for my thesis. I am using ansys 2020 R2. I find a problem in the solution of the prestressed (where the prestress is given by the centrifugal force) case for a NON symmetric geometry. In particular, the solution in the rotating reference system seems to produce negative and zero frequencies as I was dealing with a symmetric part. This holds both for the example at https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v202/en/ans_str/strllinpertrotmach.html and, also for my case study which is a rotating bladed disc with a shaft attached and a cantilever mount (in other words a stodola-green rotor with blades). The error that comes out is that of a large negative pivot found. In the attachment I send you the routine used for the solution and some images describing the problem.
I would really appreciate your help since this problem is taking me away from the conclusion of my master thesis.
Ps: jsut for completeness, the part is meshed with solid185 elements and they are no distorted elements.