Hello. I was doing a simulation of a pressure vessel. When I tried to get the results, I got the following error:
^^^ USER FATAL MESSAGE 9137 (SEKRRS)
^^^ RUN TERMINATED DUE TO EXCESSIVE PIVOT RATIOS IN MATRIX KLL.
^^^ USER ACTION: CONSTRAIN MECHANISMS WITH SPCI OR SUPORTI ENTRIES OR SPECIFY PARAM,BAILOUT,-1 TO
^^^ CONTINUE THE RUN WITH MECHANISMS.
Does anyone knows how to correct this?
This is the typical novice error message received when you gorgot to prescribe the boundary conditions to your FE model, or the ones defined are not anough to prevent rigid body motions, and then you have a mechanism, ie, your matrix is singular (you have a zero in the diagonal). Take a look to the following post in my blog in the following address (is written in Spanish, but you always can use Google Translator):
A trick a use a lot to detect where the mechanism is located is to run a normal eigenvalue analysis using NX NASTRAN (SOL103) and animate the first mode shape with zero value: