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Mass and stifness matrix

Posted Mar 24, 2011, 6:09 a.m. EDT MEMS & Nanotechnology, Piezoelectric Devices, LiveLink for MATLAB 1 Reply

Ilias Papalaios
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I am modeling a piezoelectric structure in an eigenfreq analysis.

i export my model in matlab as fem and as state space model

Mass matrix is zero, why? (i use assemble command)

M matrix in state space model is zero, why?

Any help woulb be great, thanks in advance
1 Reply Last Post Dec 26, 2011, 7:12 a.m. EST
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Hello Ilias Papalaios

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Jisoo Kim
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Posted: 1 decade ago Dec 26, 2011, 7:12 a.m. EST
Hi Ilias.
I found that I can help you in a manual.

assemble has an empty default value for the property Eigname. So if you want to assemble the matrices for an eigenvalue problem formulated using and eigenvalue name, then the Eigname property must be given. If the variable name lambda is used and if Eigname is not set (and if lambda is not defined in another way), then this variable is evaluated to zero.

Thank you.
Hi Ilias. I found that I can help you in a manual. assemble has an empty default value for the property Eigname. So if you want to assemble the matrices for an eigenvalue problem formulated using and eigenvalue name, then the Eigname property must be given. If the variable name lambda is used and if Eigname is not set (and if lambda is not defined in another way), then this variable is evaluated to zero. Thank you.

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