override negative pivots
override negative pivots
(OP)
Hi all,
I try to "override" a negative pivot. I am running a static linear analysis with a model containing a superelement. The stiffness matrix inside the SE is created outside Ansys and results from different calculations.
The matrix in SE is not positive definite, but the whole model (including SE) is "positive" (checked by combining all stiffness matrices in another program). Actually the model is really overconstrained but I still get a "large negative pivot" message.
Principally I suppose that even negative pivots in small regions of the model should result in great values of result DOF provided the rest of the model is "positive".
I tryed to switch the pivot chcking off by PIVCHECK,OFF but other errors stop the solution.
Has anybody encountered similar problem?
Thanks H-up
I try to "override" a negative pivot. I am running a static linear analysis with a model containing a superelement. The stiffness matrix inside the SE is created outside Ansys and results from different calculations.
The matrix in SE is not positive definite, but the whole model (including SE) is "positive" (checked by combining all stiffness matrices in another program). Actually the model is really overconstrained but I still get a "large negative pivot" message.
Principally I suppose that even negative pivots in small regions of the model should result in great values of result DOF provided the rest of the model is "positive".
I tryed to switch the pivot chcking off by PIVCHECK,OFF but other errors stop the solution.
Has anybody encountered similar problem?
Thanks H-up





RE: override negative pivots
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RE: override negative pivots
Therefor I think the problem should have a physical solution.
RE: override negative pivots
RE: override negative pivots
H-up