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Resistance of deformed body (Structural Mechanics)
Posted 09.09.2009, 04:18 GMT-4 2 Replies
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Hello. I am wondering if there is a way to integrate over a deformed subdomain in postprocessing. Specifically I am going to integrate p/dA in the x-direction of a curved bar, that is, the resistance (with constant resistivity p).
I have not even yet figured out how to do the same kind of integration over a non-deformed subdomain in comsol, so I am at the moment quite far from a solution.
Is there anyone who can help me? =)
I have not even yet figured out how to do the same kind of integration over a non-deformed subdomain in comsol, so I am at the moment quite far from a solution.
Is there anyone who can help me? =)
2 Replies Last Post 19.09.2009, 08:38 GMT-4
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Posted:
2 decades ago
Another related question: Is it possible to save the deformed shape of a subdomain in postproscessing as a new subdomain?
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Posted:
2 decades ago
Hello
I'm not sure I understand correctly your question but here are a few comments:
First to let us out here better understand your question pls add some units, by default in structral "p" is the pressure, for me in [Pa], so I'm not catching which "resistance" you are referring to.
Now integration over areas: by default you have an initial "frame" generally x,y,z to work with, giving structural deformation u,v,w for each point considered.
But you can also go into the "physics" settings and turn "deformed frame" ON. then you get a new "deformed" frame x2,y2,z2 with basically x2=x+u, y2=y+v etc for each point. Then when you define an integration variable you must specify on which frame you want to integrate, the reference or the deformed.
My main use of the deformed frame in structural is that on the boundary of my solid I get then defined the surface normals nx2, ny2, nz2 of the deformed structure, and this allows me to calculate where the average normal is pointing for my optical surfaces (I'm doing a lot of precise optomechanics FEM studies).
COMSOL is not very clearly defining exactly over which value they integrate, it's "implicit", but not always evident, especially for new users. Personally I would have preferred to see more clearly written out on the GUI's the full formula in a more classical mathematical way.
It's a question of learning the implicit of COMSOL, but as one start quickly to do mix many physics, with many "implicit" it can be confusing.
Hope this helps a littele on the way
Good luck
Ivar
I'm not sure I understand correctly your question but here are a few comments:
First to let us out here better understand your question pls add some units, by default in structral "p" is the pressure, for me in [Pa], so I'm not catching which "resistance" you are referring to.
Now integration over areas: by default you have an initial "frame" generally x,y,z to work with, giving structural deformation u,v,w for each point considered.
But you can also go into the "physics" settings and turn "deformed frame" ON. then you get a new "deformed" frame x2,y2,z2 with basically x2=x+u, y2=y+v etc for each point. Then when you define an integration variable you must specify on which frame you want to integrate, the reference or the deformed.
My main use of the deformed frame in structural is that on the boundary of my solid I get then defined the surface normals nx2, ny2, nz2 of the deformed structure, and this allows me to calculate where the average normal is pointing for my optical surfaces (I'm doing a lot of precise optomechanics FEM studies).
COMSOL is not very clearly defining exactly over which value they integrate, it's "implicit", but not always evident, especially for new users. Personally I would have preferred to see more clearly written out on the GUI's the full formula in a more classical mathematical way.
It's a question of learning the implicit of COMSOL, but as one start quickly to do mix many physics, with many "implicit" it can be confusing.
Hope this helps a littele on the way
Good luck
Ivar