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Square Membrane Eigenfrequency
Posted 25 mars 2011, 13:38 UTC−4 MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Structural Mechanics Version 4.1 1 Reply
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Hello,
I am attempting to simply solve for the first 10 eigenfrequencies of a square Si3N4 membrane. I have two geometries and implemented very similar conditions to a successful simulation I have completed in 3.5, however I get relative error and relative tolerances problems every time I run. I have tried to re-scale my mesh to allow for smoother conversion and less memory use. But I can't seem to solve this issue...
I have attached two files, the second of which is the one I prefer and have used in past versions of COMSOL.
Any help would be greatly appreciated.
Thank you,
Daniel
I am attempting to simply solve for the first 10 eigenfrequencies of a square Si3N4 membrane. I have two geometries and implemented very similar conditions to a successful simulation I have completed in 3.5, however I get relative error and relative tolerances problems every time I run. I have tried to re-scale my mesh to allow for smoother conversion and less memory use. But I can't seem to solve this issue...
I have attached two files, the second of which is the one I prefer and have used in past versions of COMSOL.
Any help would be greatly appreciated.
Thank you,
Daniel
Attachments:
1 Reply Last Post 26 mars 2011, 06:59 UTC−4
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Posted:
1 decade ago
Hi
first of all have you checked the influence of the mesh, using mapped/sweep mesh versus thets, and using several in the thickness, not "just" one ... ?
it would probably make your 2 models more similar.
By the way, if you restrain the domain, its not necessary to restrain the boundaries
And I use rather the "fixed" BC, it's in fact the same as what you have made, if you look at the equations beneath (turn them on in the options menu). Then also if you restrain the full domain of your frame, why not "just " forget it.
Or use a more realistic fixture, such that the "true" modes including the frame show up
The convergence error I get too rather often in V4 for eigenfrequency analysis, not sure exactly how to get around either, but I notice that my results are mostly OK
By the way get hands on the latest patch, tehre are several issues corrected since yours
--
Good luck
Ivar
first of all have you checked the influence of the mesh, using mapped/sweep mesh versus thets, and using several in the thickness, not "just" one ... ?
it would probably make your 2 models more similar.
By the way, if you restrain the domain, its not necessary to restrain the boundaries
And I use rather the "fixed" BC, it's in fact the same as what you have made, if you look at the equations beneath (turn them on in the options menu). Then also if you restrain the full domain of your frame, why not "just " forget it.
Or use a more realistic fixture, such that the "true" modes including the frame show up
The convergence error I get too rather often in V4 for eigenfrequency analysis, not sure exactly how to get around either, but I notice that my results are mostly OK
By the way get hands on the latest patch, tehre are several issues corrected since yours
--
Good luck
Ivar