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Automatically enable/disable constraints/intial values basing on the study step

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Dear community, I'm Giulio and I'm fairly new to comsol.

My problem is quite simple but, at the moment, I'm not able to find a solution elsewhere.

My study has this structure: 1) Eigenfrequency study of a part (lets call it A) of the system to find its eigenmodes. 2) Use the eigenmodes of A as initial values for A in a time dependent study of the whole system. (in my case I use withsol('sol1',w,setind(lambda,3)), for instance, to select the z-compontent of the displacemente of the third auto-mode).

I want to re-iterate this process with a parameter sweep, changing the size of A. Therefore I have to repeat the eigenfrequency study for each parameter value, to retrieve the eigen-displacement of A.

Is there a way to (1) disable a part of the geometry and initial values node=> perform eigenfrequency study (2) enable all the geometry AND initial values for A => perform t-dependent study in an automatic way (parameter study?).

Otherwise, the solution, migh be study all the eigenmodes for all the parameters in a first time and perform all the t-dep studies in a second time. But it involves twice the meshing and it's probably not the best way to proceed.

Thank you masters.


2 Replies Last Post 27.02.2018, 09:45 GMT-5

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Posted: 7 years ago 27.02.2018, 08:11 GMT-5

Hi Giulio,

Is the option "Modify model configuration for study step" in the Study Step configuration can do what you want ? Parts of the model can be activated of disabled here ...

Best regards, Etienne

Hi Giulio, Is the option "Modify model configuration for study step" in the Study Step configuration can do what you want ? Parts of the model can be activated of disabled here ... Best regards, Etienne


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Posted: 7 years ago 27.02.2018, 09:45 GMT-5

Hi Giulio,

Is the option "Modify model configuration for study step" in the Study Step configuration can do what you want ? Parts of the model can be activated of disabled here ...

Best regards, Etienne

It is. I very apologise for having not noticied it by myself. Btw I'm using the version 6.3 of comsol and I only have the possibility to change the physics and not the geometry. However i suppressed the unwanted automodes fixing the displacement of the notA part to 0 .

Now I had another trouble: I change a geometrical feature on A and I perform the parametric eigenmode study. After that I want to study its first 3 eighenmodes with a time dependent solver.
I can't find a way to perform a parameter sweep only on a study step. Furthermore, every time i change the n (eigenmode number) the solver restart with a new mesh, even though nothing changed on the geometry of the system.

Thank you very much for your help. :)

>Hi Giulio, > >Is the option "Modify model configuration for study step" in the Study Step configuration can do what you want ? Parts of the model can be activated of disabled here ... > >Best regards, >Etienne It is. I very apologise for having not noticied it by myself. Btw I'm using the version 6.3 of comsol and I only have the possibility to change the physics and not the geometry. However i suppressed the unwanted automodes fixing the displacement of the notA part to 0 . Now I had another trouble: I change a geometrical feature on A and I perform the parametric eigenmode study. After that I want to study its first 3 eighenmodes with a time dependent solver. I can't find a way to perform a parameter sweep only on a study step. Furthermore, every time i change the n (eigenmode number) the solver restart with a new mesh, even though nothing changed on the geometry of the system. Thank you very much for your help. :)

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