General Mechanical

General Mechanical

Solver pivot warning / under constrained model

    • Dominik Kolář
      Subscriber

      Hello,

      I´m trying to do a simplified model of a ferris wheel. I created a beam model in DesignModeler from line bodies and then formed a new part of them. Once I try to solve it in Mechanical Solver pivot warnings appear also with error been detected in the .. (UY...) degree of freedom of node ... (941...). Can someone help me with the solution? Thank you very much. 

      The messages:

      "Solver pivot warnings or 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."

      "A solver pivot warning or error has been detected in the UY degree of freedom of node 941 located in Body1. 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. You may select the offending object and/or geometry via RMB on this warning in the Messages window."

       

      Link for geometry file:

      https://drive.google.com/file/d/1NbEiYeG1g6yeA4TNkTw7CryAL2D_6Uzd/view?usp=share_link

    • Erik Kostson
      Ansys Employee

       

       

      Make a modal analysis to see if the beams are all connected (if they are not then use multi-body part in design modeler). If all is ok (so beams are all connected as seen from modal analysis), then you need to apply appopriate constraints to prevent rigid body motion/rotation in the static analysis.

      Erik

       

       

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