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zero pivot nodes

Abaqus Eigen Value Analysis Error

Submitted by paulamil on
research
ABAQUS
zero pivot nodes
Factorization Error

Hello,

I am having issues running an Eigen value simulation on a bridge model that I have developed. The model consists of a bridge super-structure supported by pinned connections on the ends of the bridge length and a roller support in the middle.

The model runs without errors when I do not request an Eigen value analysis, but aborts when I request an Eigen analysis. The message file sites the cause as a factorization error. Warnings also appear stating a zero pivot when releasing the 1st dof of the nodes associated with the roller connection.

Model Overconstraints

Submitted by gprinz on
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ABAQUS
zero pivot nodes
NLGEOM

Hello all,

I have created a 3-d dynamic model in ABAQUS using shell elements.  When I run the analysis I get several warning messages indicating that I have zero pivot nodes.  When I locate where these nodes are, I find that they are in the middle of my beam (modeled with shell elements) away from any boundary conditions.  Does anyone know why ABAQUS is indicating these inconsistent overconstraints in the middle of my model???  The analysis fails to converge when NLGEOM=yes but has no problems converging when NLGEOM is removed.

Thanks in advance

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