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Dimension Problems - AC/DC Module

Posted Jun 1, 2010, 4:30 a.m. EDT Version 4.0a 4 Replies

Nihit Madan
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Hi All,

I am trying to model Ogranic Light Emitting Diodes (OLED's) using the Conductive media DC under the Statics,Electric in the AC/DC module(Comsol 3.5a).
The dimesions of the OLED's are 120mm by 40 mm and the thickness is 250 nm, when I try to extrude the 2D geom to 3D with extrusion value of 250 nm,i get an error 2015, cannot find a valid topology for the generated geometric object.
I dont seem to understand this error.What can be done when working with such low values of dimension in comsol.
please help.

Warm Regards,
Nihit.
4 Replies Last Post Mar 15, 2011, 12:17 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jun 1, 2010, 5:42 a.m. EDT
Hi

but whith such dimensional ratios 120mm:0.25um = 480'000:1 are you sure you cannot use rather thin surface effects, as what is happening in the tichkness requires typically several elements and then you restrain the horizontal size too, and you will end up with something like 3-5*480'000^2 items. That would require really a super computer, no ?

Furthermore you should check your "repair" tolerance, that by default is at 10um (in V3.5) when you work with small or thin geometries

Hope this helps
Ivar

Hi but whith such dimensional ratios 120mm:0.25um = 480'000:1 are you sure you cannot use rather thin surface effects, as what is happening in the tichkness requires typically several elements and then you restrain the horizontal size too, and you will end up with something like 3-5*480'000^2 items. That would require really a super computer, no ? Furthermore you should check your "repair" tolerance, that by default is at 10um (in V3.5) when you work with small or thin geometries Hope this helps Ivar
Mike Gibbs
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Posted: 1 decade ago Mar 15, 2011, 11:56 a.m. EDT
I'm having the same problem modelling a MEMS cantilever. I've tried adjusting the tolerance - no help. Earlier version of COMSOL did not have this error, and coped with my dimensions. Sugestions?
I'm having the same problem modelling a MEMS cantilever. I've tried adjusting the tolerance - no help. Earlier version of COMSOL did not have this error, and coped with my dimensions. Sugestions?
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 15, 2011, 12:12 p.m. EDT
Hi

I have made several "thin" features in V4 (as before in v3.5a), cannot remember any special trick, apart from the tolerance settings.

You have possibly the CAD versus COMSOL kernel option (but I believe that is for the "import", would ahve to check again, but I do not have access to COMSOl just now ;)

For me V4.1 is working as good if not better than v3.5a now, but it took me quite some time to find back all the buttons and tweaks ;)

--
Good luck
Ivar
Hi I have made several "thin" features in V4 (as before in v3.5a), cannot remember any special trick, apart from the tolerance settings. You have possibly the CAD versus COMSOL kernel option (but I believe that is for the "import", would ahve to check again, but I do not have access to COMSOl just now ;) For me V4.1 is working as good if not better than v3.5a now, but it took me quite some time to find back all the buttons and tweaks ;) -- Good luck Ivar
Mike Gibbs
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Posted: 1 decade ago Mar 15, 2011, 12:17 p.m. EDT
My dimensions are defined in geometry by two planes each 40mmx4mm. One is extruded below the workplane by 400um to form the substrate, the other needs to be extruded by 0.072um above the workplane to define the second layer. It is at this step (tolerance tried from 10^6 to 10^10) that I get the problem.
My dimensions are defined in geometry by two planes each 40mmx4mm. One is extruded below the workplane by 400um to form the substrate, the other needs to be extruded by 0.072um above the workplane to define the second layer. It is at this step (tolerance tried from 10^6 to 10^10) that I get the problem.

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