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Eigenvectors in Modal analysis

Eigenvectors in Modal analysis

Eigenvectors in Modal analysis

(OP)
Hello!

I am running my first simulation in Abaqus about a supported-free beam and I got the natural frequencies and mode shapes, but I need the Modal Matrix, in which appear all the EIGENVECTORS so I can calculate the Modal Assurance Criterion to make a comparison with another simulation. I know this matrix should be quite large, n rows x r columns, being n = number of finite elements x degrees of freedom, and r = mode shapes.

Does anyone know where can I find this matrix in Abaqus? In the Data File I can only see the EIGENVALUE and the FREQUENCY and I can not create a Report with the displacemnet of all the nodes.

Thanks!

RE: Eigenvectors in Modal analysis

Hi
Have you already find the matrix with the eigenvectors? I am searching it
Kind regards

RE: Eigenvectors in Modal analysis

The eigenvector is just the displacements and rotations of for each shape. I think n would be just the number of DOF (I don't see why the number of elements has anything to do with it). That said, all you would need to is output the displacments/rotations at each node (which will be normalized) and those are essentially your eigenvectors.

Brian
www.espcomposites.com

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