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Posted:
1 decade ago
Apr 5, 2010, 10:25 p.m. EDT
I believe the standard way everyone does it is to try a refinement of the mesh and look at the change in results. If the results change so little that you don't care, then you know the mesh is fine enough.
Another way to do this (I think) is to turn on Adaptive Meshing in the software and let the software refine the mesh automatically in regions where it sees strong gradients. You can have the software continue this process until some convergence criteria you can set.
I'll be interested to learn from anyone who wants to point out a better method.
-Jeff
I believe the standard way everyone does it is to try a refinement of the mesh and look at the change in results. If the results change so little that you don't care, then you know the mesh is fine enough.
Another way to do this (I think) is to turn on Adaptive Meshing in the software and let the software refine the mesh automatically in regions where it sees strong gradients. You can have the software continue this process until some convergence criteria you can set.
I'll be interested to learn from anyone who wants to point out a better method.
-Jeff
Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted:
1 decade ago
Apr 6, 2010, 2:11 a.m. EDT
Hi
That's indeed the metod I apply, normally after a refinement I expect less than 5-10% change in results to be happy, but often the need for refinements is very local, therefore it often becomes heavy computationaly to refine the full model. Then adaptive meshing is nice, but it need some tweaking. Typically in structural, or RF you get some stress or field concetrations in sharp corners, these are refined with the adaptive meshing but the L2 norm used does not seem to conentrate very strongly on these, it refines quite well everywhere, which means that the computation time increases quite a lot too.
I finish generally manually, but to really observe the places where the mesh is poor, one need to turn off the mesh visualisatiion refinment: "Posprocessing - Plot parameters, General Tab" "element refinement = 1" and then use a "flat" coloring, possible a "wireframe" rendering.
Have fun Comsoling
Ivar
Hi
That's indeed the metod I apply, normally after a refinement I expect less than 5-10% change in results to be happy, but often the need for refinements is very local, therefore it often becomes heavy computationaly to refine the full model. Then adaptive meshing is nice, but it need some tweaking. Typically in structural, or RF you get some stress or field concetrations in sharp corners, these are refined with the adaptive meshing but the L2 norm used does not seem to conentrate very strongly on these, it refines quite well everywhere, which means that the computation time increases quite a lot too.
I finish generally manually, but to really observe the places where the mesh is poor, one need to turn off the mesh visualisatiion refinment: "Posprocessing - Plot parameters, General Tab" "element refinement = 1" and then use a "flat" coloring, possible a "wireframe" rendering.
Have fun Comsoling
Ivar
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Posted:
1 decade ago
Apr 7, 2010, 11:33 a.m. EDT
I zoomed in the region of high stress concentration, then I refined the mesh locally and the result has converged with only 1000 elements instead of 40 000 in other software. I am still with comsol
thank you
I zoomed in the region of high stress concentration, then I refined the mesh locally and the result has converged with only 1000 elements instead of 40 000 in other software. I am still with comsol
thank you
Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted:
1 decade ago
Apr 7, 2010, 1:10 p.m. EDT
Hi
Good job then, nice to hear
Have fun Comsoling
Ivar
Hi
Good job then, nice to hear
Have fun Comsoling
Ivar
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Posted:
1 decade ago
Apr 15, 2010, 6:31 a.m. EDT
When I measure the coefficient of stress concentration KI result converges only for 1000 elements, but when I want to calculate the von Mises stress, the maximum value always increases until the memory limit comsol.
What is the way to converge the value of Von Mises with less mesh possible.
thank you in advance
When I measure the coefficient of stress concentration KI result converges only for 1000 elements, but when I want to calculate the von Mises stress, the maximum value always increases until the memory limit comsol.
What is the way to converge the value of Von Mises with less mesh possible.
thank you in advance
