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Mass matrix is Zero

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Hello,
I have built a model using pressure acoustic frequency domain module. I have tried to extract state space matrices using MATLAB Livelink. The problem is my mass matrix turns to null matrix. As I have read in the other discussions the problem could be related to the type of boundary conditions. My model is a simple cylindrical tube, I have specified pressure boundary condition to the inlet, sound soft boundary to the outlet and the others are sound hard boundary.
It will be great if someone gives me some hints that how can I solve my problem.

Kind regards,

Shahin Mohammadnejad

0 Replies Last Post 2016年7月21日 GMT-4 13:55
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Hello shahin mohammadnejad

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