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Why COMSOL still requires the Young's modulus and Poisson ratio when defining an anisotropic material?

Posted Feb 6, 2013, 12:31 p.m. EST Structural Mechanics Version 4.3a 6 Replies

Michael Renaud
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Hi all,

I want to play with Comsol for 3D simulations of linear elastic material. The materials are anisotropic so that I define elasticity matrices for them. But Comsol still requires me to give values for the Young's modulus and Poisson ratio (there is the little "stop" red sign in front of these properties). Why is that?

Thanks
6 Replies Last Post Feb 13, 2016, 6:36 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Feb 6, 2013, 3:15 p.m. EST
Hi

strange, I have noticed that once you have changed the physics node to non-linear material, and that your domains are correctly set up, the demand on material properties are changed from Young Poisson, to the appropriate tensor or Lamé constants.

But you need to go down into the solid sub nodes, change and up into the material nodes to have COMSOLl to notice the change of the need

--
Good luck
Ivar
Hi strange, I have noticed that once you have changed the physics node to non-linear material, and that your domains are correctly set up, the demand on material properties are changed from Young Poisson, to the appropriate tensor or Lamé constants. But you need to go down into the solid sub nodes, change and up into the material nodes to have COMSOLl to notice the change of the need -- Good luck Ivar
Michael Renaud
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Posted: 1 decade ago Feb 7, 2013, 3:55 a.m. EST
Hi Ivar,

I am very grateful that you're always here to help people :)
Yes, it is required to specify in the physics node the way material is represented, either in terms of appropriate tensor or in terms of Young modulus and co.

Thanks
Hi Ivar, I am very grateful that you're always here to help people :) Yes, it is required to specify in the physics node the way material is represented, either in terms of appropriate tensor or in terms of Young modulus and co. Thanks
Mayank Dhull
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Posted: 10 years ago Jan 29, 2015, 2:22 a.m. EST
Hi,
I have the same problem. Can you please explain how to get rid of it?

Thanks
Hi, I have the same problem. Can you please explain how to get rid of it? Thanks
Mayank Dhull
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Posted: 10 years ago Feb 1, 2015, 4:30 a.m. EST
"But you need to go down into the solid sub nodes, change and up into the material nodes to have COMSOLl to notice the change of the need"

Can you please explain how do i do it. I am using Joule Heating module.

Thanks
"But you need to go down into the solid sub nodes, change and up into the material nodes to have COMSOLl to notice the change of the need" Can you please explain how do i do it. I am using Joule Heating module. Thanks
Magnus Ringh COMSOL Employee

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Posted: 10 years ago Feb 2, 2015, 2:43 a.m. EST
Hi,

The material properties needed depend on the elastic or nonlinear material model that you use. For example, if you have a Linear Elastic Material node, you specify the linear elastic material in its Settings window. If you choose Isotropic from the Solid model list, you can choose how to specify it using the Specify list. The default is to specify Young's modulus and Poisson's ratio. If those properties are missing from the material in use, the Material node will have a red cross in its lower-left corner. If you, for example, instead have defined the elasticity matrix for an anisotropic material, then the red cross disappears if you select Anisotropic from the Solid model list (then the material properties defined match the material model defined in the physics). The indication in the Material node is updated immediately, so you don't need to revisit it unless you want to add some missing properties. To summarize, which material properties that are needed depends on the physics and material models that you use.

Best regards,
Magnus Ringh, COMSOL
Hi, The material properties needed depend on the elastic or nonlinear material model that you use. For example, if you have a Linear Elastic Material node, you specify the linear elastic material in its Settings window. If you choose Isotropic from the Solid model list, you can choose how to specify it using the Specify list. The default is to specify Young's modulus and Poisson's ratio. If those properties are missing from the material in use, the Material node will have a red cross in its lower-left corner. If you, for example, instead have defined the elasticity matrix for an anisotropic material, then the red cross disappears if you select Anisotropic from the Solid model list (then the material properties defined match the material model defined in the physics). The indication in the Material node is updated immediately, so you don't need to revisit it unless you want to add some missing properties. To summarize, which material properties that are needed depends on the physics and material models that you use. Best regards, Magnus Ringh, COMSOL
Mahmood Waqas
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Posted: 9 years ago Feb 13, 2016, 6:36 a.m. EST
Hi everyone.

Can anyone please elaborate the reason to get a notification that the solution is not converged? What is convergence tolerance related to? geometry or what else.

Regards,

Waqas.
Hi everyone. Can anyone please elaborate the reason to get a notification that the solution is not converged? What is convergence tolerance related to? geometry or what else. Regards, Waqas.

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