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Stress in 3D in blocks by temperature reduction

Posted 20 sept. 2010, 22:46 UTC−4 MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Structural Mechanics 7 Replies

Piyush Bajaj
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Hi,

I am trying to model the stress in three plates touching each other in the z-direction becuase of the reduction in temperature in the top plate. All the edges are fixed except the top plate's top surface and only the top plate has a thermal conductivity. However, after building the geometry and meshing when I press the compute button the following error comes up:

Failed to evaluate expression
Expression: 1000000*mod1.solid.disp

Failed to evaluate operator
Operator: mean
Geometry: 1
Boundary: 6 9
Plot: surf1 (surface)

Can anyone explain me how can I model this simple system and what is the reason I am getting this error?

Thanks
7 Replies Last Post 9 nov. 2013, 17:46 UTC−5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 21 sept. 2010, 01:13 UTC−4
Hi

I understand this as the displacement = sqrt(u^2+v^...) is not defined for your domain/boundaries. Could it be that you did not select it in the model definitons ? or that some matgerial constant is not complete or not applied to all boundaries ?

--
Good luck
Ivar
Hi I understand this as the displacement = sqrt(u^2+v^...) is not defined for your domain/boundaries. Could it be that you did not select it in the model definitons ? or that some matgerial constant is not complete or not applied to all boundaries ? -- Good luck Ivar
Piyush Bajaj
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Posted: 1 decade ago 22 sept. 2010, 12:49 UTC−4
Hi Ivar,

I reduce the three plate model to a single plate and fix all the boundaries except the top surface for which I check the prescribed displacement in all the x, y and z directions. However, I still get the same error for the top surface of the single plate. Any suggestions or ideas?

Thanks


Hi Ivar, I reduce the three plate model to a single plate and fix all the boundaries except the top surface for which I check the prescribed displacement in all the x, y and z directions. However, I still get the same error for the top surface of the single plate. Any suggestions or ideas? Thanks
Piyush Bajaj
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Posted: 1 decade ago 22 sept. 2010, 13:01 UTC−4
Also, in warnings it says not all domains are meshed. But I do Mapped meshing for the entire geometry and selecte build selected. So I do not understand how are my domains not meshed.
Also, in warnings it says not all domains are meshed. But I do Mapped meshing for the entire geometry and selecte build selected. So I do not understand how are my domains not meshed.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 22 sept. 2010, 14:46 UTC−4
Hi

I have been burned a couple of times with someting similar, I had meshed all boundaries but not the volume/domain Could that be your case (rather easy in v3.5) probably not possible in V4 (to be checked)

Have you tried to use the "select remaining" in the mesh environment ? if something is selected then not everything is meshed.

--
Good luck
Ivar
Hi I have been burned a couple of times with someting similar, I had meshed all boundaries but not the volume/domain Could that be your case (rather easy in v3.5) probably not possible in V4 (to be checked) Have you tried to use the "select remaining" in the mesh environment ? if something is selected then not everything is meshed. -- Good luck Ivar
Mohsen Ekhtiari
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Posted: 1 decade ago 27 sept. 2010, 03:22 UTC−4
Hi

In comsol, when you use mapped meshing, it meshes the boundary only no the domain. So your model indeed has no solid mesh. Use Free Tetrahedral or Swept option instead.
Hi In comsol, when you use mapped meshing, it meshes the boundary only no the domain. So your model indeed has no solid mesh. Use Free Tetrahedral or Swept option instead.
Piyush Bajaj
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Posted: 1 decade ago 3 oct. 2010, 16:06 UTC−4
Hi,

Yes, when I use the treatrahedral mesh the problem goes away.

Thanks
Hi, Yes, when I use the treatrahedral mesh the problem goes away. Thanks
Arthur Chuang
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Posted: 1 decade ago 9 nov. 2013, 17:46 UTC−5
Hi Piyush,

I'm currently working on a project at UIUC. I read about your paper and was trying to use Comsol to create thermal stress between two layered plates. I was wondering if you could help me out. I have run into the message that says I have undefined value. I don't understand what it's referring to. What were the major steps you used in creating your models?

Many thanks in advance for any help!

PS. I've attached my file to this email

Arthur
Hi Piyush, I'm currently working on a project at UIUC. I read about your paper and was trying to use Comsol to create thermal stress between two layered plates. I was wondering if you could help me out. I have run into the message that says I have undefined value. I don't understand what it's referring to. What were the major steps you used in creating your models? Many thanks in advance for any help! PS. I've attached my file to this email Arthur

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