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Outputting the stiffness matrix at each time step during the simulation

Saddam Hijazi Mathematics

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Dear all,

Hello, I would like to ask you a question about extracting the stiffness Matrix K at each time step during the Comsol simulation of a non-linear unsteady elasticisity problem. I need that in order to perform model order reduction of the non-linear model.

I have seen that there are discussions which were aimed at this goal in the past but without clear solution or at least an indication that this is impossible in Comsol. The function 'mphmatrix' in Matlab has an argument called 'Solnum' but when I set it to say 24 or any other time step I got an error which says :

error using mphmatrix cannot set the property 'solnum' to '24'. allowed values are: 'auto' 'first' 'last' 'interp' 'manual' '1'

Could you please help me in answering this question ? Thank you in advance.

Best regards, Saddam


0 Replies Last Post Dec 8, 2023, 5:17 a.m. EST
COMSOL Moderator

Hello Saddam Hijazi

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