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Try eigenfrequency analysis by LMS and MBD

Posted Aug 14, 2019, 6:09 a.m. EDT Structural & Acoustics, Structural Mechanics Version 5.3a 2 Replies

Leon Chan
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Hello,

While I am trying a 1dof example to test the eigenfrequency analysis by LMS and MBD, I feel really confused that I have one model passed but with another failed which have all the parameters same but only the direction of applied force on the rigid domain. I attached my idea and the two models which I setup in Comsol5.3a windows. Does anyone have ever suffered this? Thanks a lot in advance.

Erro info: - Feature: Eigenvalue Solver 1 (sol1/e1) Singular matrix. - Detail: There are 1 degrees of freedom that do not occur in any equation (empty columns in matrix) for the variable comp1.mbd.rd1.u. at coordinates: (0,0,0), ...

2 Replies Last Post Aug 18, 2019, 7:51 a.m. EDT
Pawan Soami COMSOL Employee

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Posted: 5 years ago Aug 16, 2019, 4:29 a.m. EDT
Updated: 5 years ago Aug 16, 2019, 5:58 a.m. EDT

Dear Leon,

I had a look at your model and it seems you have missed to update the displement in the External Source node in LMS. Once you change the port-1 displacement as intop1(u) instead of intop1(w), it works as expected.

Best regards,
Pawan Soami

Dear Leon, I had a look at your model and it seems you have missed to update the displement in the External Source node in LMS. Once you change the port-1 displacement as *intop1(u)* instead of *intop1(w)*, it works as expected. Best regards, Pawan Soami
Leon Chan
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Posted: 5 years ago Aug 18, 2019, 7:51 a.m. EDT
Updated: 5 years ago Aug 18, 2019, 7:41 a.m. EDT

Dear Pawan,

Thank you very much for the help!

Best regards, Leon

Dear Pawan, Thank you very much for the help! Best regards, Leon

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