Learning Forum

[munkhunur]

Dear Sir,

Here is one question arising while designing one model.

The analysis runs without any problem while flanges are split into 2 divisions. When I split those flanges into 3 divisions, the following error message popped up, and the analysis was terminated almost in the final loading stage.

The error message was "Solver pivot warnings/ errors have been encountered during the solution. This is usually a result of an ill conditioned matrix possibly due to unreasonable material properties, an under constrained model, or contact related issues. Check results carefully..."

How to solve this problem, and why is it encountered regarding element division?

Thanks

UNUR

[Ashish Khemka]

Solver pivot error generally indicates rigid body motion. Please see if the parts are constrained properly.

Regards Ashish Khemka

[munkhunur]

Dear Ashish Khemka In advance, thank you so much for your reply.
So, How can I find that rigid body easily in the results?
Could this warning be that problem?
***********************
*** WARNING ***CP =330.301TIME= 22:45:24
There is at least 1 small equation solver pivot term (e.g., at the UZ
degree of freedom of node 6225) which may indicate a numerically
unstable model.Please check your results carefully.
EQUIL ITER8 COMPLETED.NEW TRIANG MATRIX.MAX DOF INC=0.3016E-03
DISP CONVERGENCE VALUE=0.1703E-03CRITERION=0.5779E-02 <<< CONVERGED
LINE SEARCH PARAMETER =0.5646SCALED MAX DOF INC =0.1703E-03
THE CONTACT STATUS HAS CHANGED AT3CONTACT POINTS
FORCE CONVERGENCE VALUE=275.9CRITERION=223.4
EQUIL ITER9 COMPLETED.NEW TRIANG MATRIX.MAX DOF INC= -0.3010E-03
DISP CONVERGENCE VALUE=0.3010E-03CRITERION=0.5897E-02 <<< CONVERGED
LINE SEARCH PARAMETER =1.000SCALED MAX DOF INC = -0.3010E-03
THE CONTACT STATUS HAS CHANGED AT5CONTACT POINTS
FORCE CONVERGENCE VALUE=134.3CRITERION=455.8<<< CONVERGED
>>> SOLUTION CONVERGED AFTER EQUILIBRIUM ITERATION
*******
Regards Unur

[munkhunur]