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Recent Changes to Frames...

Posted 2011/11/10 16:31 GMT-5 Version 4.2a 3 Replies

Andrew Prudil Nuclear Materials
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I have a question about how frames have been changed in recent versions of Comsol.

I have a model which includes the solid-mechanics module. In past versions of COMSOL there was an option for "deformation control spatial frame". I cannot find this option in 4.2a.

Currently, my material and spatial frame coordinates are equal. If I calculate r/R or z/Z they equal 1 for all my time-steps.

Any ideas how to enable deformed spatial frames?
3 Replies Last Post 2011/11/13 19:17 GMT-5
Andrew Prudil Nuclear Materials
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Posted: 1 decade ago 2011/11/12 22:36 GMT-5
I figured this out. The material and spatial frame variables only appear to be different in my model if I select the option for "include geometric non-linearity". I just figured I'd post here in case anyone else is having the same problem.
I figured this out. The material and spatial frame variables only appear to be different in my model if I select the option for "include geometric non-linearity". I just figured I'd post here in case anyone else is having the same problem.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2011/11/13 3:55 GMT-5
Hi

I believe there are more here, thanks for pointing this out ;)

Below I have added an example model file of 4.2a change in "Solid Spatial Frame use:
I notice now (COMSOL pls correct if wrong ;) that the
Spatial Frame is always defined by a lower case x,y,z while the Material Frame is now always X,Y,Z. And the casing does not change dependent of selections, as before in the previous verions.

BUT: x=X+u, y=Y+v ... ONLY if
"Study - Stationary - (x) Include geometric non-linearity"
is checked (this point is NOT (yet?) mentionned in the related Dynamic Help pages).

But, the difference of small displacement and large displacements for the definition of the stress calculation is also (must be TBC) related to this check box, EXCEPT if the user has checked the
"Solid - Linear Elastic Material - (x) FORCE Linear Strain"
box. And this is explained at the end of the related Dynamic Help page.

This is so far my understanding, but I have not yet manage to identify all changes in the equation view due to the settings of these check boxes, such to consolidate my understanding

Pls take this as TBC so far (I'm not "COMSOL" and I do not know the interiour of the software more than any other user)

--
Good luck
Ivar
Hi I believe there are more here, thanks for pointing this out ;) Below I have added an example model file of 4.2a change in "Solid Spatial Frame use: I notice now (COMSOL pls correct if wrong ;) that the Spatial Frame is always defined by a lower case x,y,z while the Material Frame is now always X,Y,Z. And the casing does not change dependent of selections, as before in the previous verions. BUT: x=X+u, y=Y+v ... ONLY if "Study - Stationary - (x) Include geometric non-linearity" is checked (this point is NOT (yet?) mentionned in the related Dynamic Help pages). But, the difference of small displacement and large displacements for the definition of the stress calculation is also (must be TBC) related to this check box, EXCEPT if the user has checked the "Solid - Linear Elastic Material - (x) FORCE Linear Strain" box. And this is explained at the end of the related Dynamic Help page. This is so far my understanding, but I have not yet manage to identify all changes in the equation view due to the settings of these check boxes, such to consolidate my understanding Pls take this as TBC so far (I'm not "COMSOL" and I do not know the interiour of the software more than any other user) -- Good luck Ivar
Andrew Prudil Nuclear Materials
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Posted: 1 decade ago 2011/11/13 19:17 GMT-5
That does clear some stuff up.
Thanks for the reply Ivar.
That does clear some stuff up. Thanks for the reply Ivar.

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