Eigenfrequency Post-Processing OptiStruct

Rahul_P1
Rahul_P1
Altair Employee
edited October 2020 in Community Q&A

Hello,

what is being displayed when looking at the Eigen frequencies in HyperView (Analysis: EIGRL, Solver: OptiStruct)? (Result type: Eigen Mode Mag) I.e. how should you interpret the deformation that is being displayed? Something physical or just to give a qualitative demonstration of the shape of the Eigen mode?

If I compare an OptiStruct EIGRL analysis to Abaqus Frequency Analysis, I get the same Eigen frequencies and modes but the deformation that is presented by HyperView is different when looking at the EIGRL analysis results. Abaqus shows 'displacement' and HyperView 'Eigen Mode (Mag)'. And the 'Eigen Mode (Mag)' seems to be around 300-times the Abaqus 'displacement' with my example.

Deformation factor is set to 1.0.

See the figure enclosed, where the original geometry is wireframed. I am wondering why this deformation that is displayed in HV is so large.
48jf5-eigfr1.png

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Answers

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited September 2014

    Seppaelae,

    You are basically looking at mode shapes not the displacement, It is indicative of the shape of vibration that the model will exhibit (in say perhaps a resonant condition)

    You can request for the displacement using the global output request in the control cards and contour this to compare,

    h6rmw-1.JPG
    04bj2-2.JPG

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