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Extract stiffness matrices and mode shapes from model
Posted Jul 3, 2023, 5:40 a.m. EDT Acoustics & Vibrations, LiveLink for MATLAB, Structural Dynamics Version 6.1 0 Replies
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Hi all,
I am working with a 2-step model, in which Eigenfrequency and mode shapes are calculated for a prestressed plate structure.
- The first step is Stationary, which computes the effect of prestress on the system.
- The second step is Eigenfrequency, which computes the frequencies and modes.
The second step should conduct the following analysis: ( (K+G) - w^2 M ) x = 0 where K is the standard stiffness matrix, G is the geometric stiffness matrix which is computed based on the prestress, w is the eigenfrequency, M is the mass matrix and x is the mode shape.
I would like to extract K, G and x using LiveLink commands, to use them in an optimization loop that runs in MATLAB.
Two questions: 1. When using mphmatrix(model,name,'Out',{'Kc'}) on the eigenfrequency step, one can extract "K" - is this only the aforementioned K or does it also contain "G" ? 2. How does one get the eigenvectors? I was not able to extract them ...
Gratefully looking forward to your replies,
Kaap H .
Hello Hendrik
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