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In rectangular, anisotropic material

Posted Jun 18, 2018, 3:46 a.m. EDT Structural & Acoustics, Heat Transfer & Phase Change 2 Replies

Song Changhwan
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I use comsol to simulate microscale heat transfer. I made geometry with two rectangular pieces. I entered the material directly, but I have some questions. The diamond material I want to apply has the property of anisotropic, but the values of cross-plane and in-plane are different. In the case of 3D, we know that we apply c11 in the object direction and c22 and c33 in the vertical direction according to the direction of the material. In 2D rectangular, we do not know how to write cross-plane and in-plane in the matrix. Anisotropic material is c11 in x direction and c22 in y direction in graphic window regardless of dimension?

2 Replies Last Post Jun 18, 2018, 12:34 p.m. EDT
Bate Papo
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Posted: 6 years ago Jun 18, 2018, 11:22 a.m. EDT

Hi Song Changhwan

I think that in 2D Heat Transfer (x and y coordinates), the temperature in the z-direction is assumed equal for each (x,y). Meaning that the temperature distribution for the z-direction is constant.

Assuming your material defined as: plane - xy, cross plane - z: You won't see any anisotropy.

However if you set up your 2D model as x being the x of the material, and y being the z direction of the 3D plane, then you be able to define your anisotropy.

If this cross section is not what you're looking for (for example if you need to account for a finite xy plane) then I guess your problem can only be solved in 3D.

Hi Song Changhwan I think that in 2D Heat Transfer (x and y coordinates), the temperature in the z-direction is assumed equal for each (x,y). Meaning that the temperature distribution for the z-direction is constant. Assuming your material defined as: plane - xy, cross plane - z: You won't see any anisotropy. However if you set up your 2D model as x being the x of the material, and y being the z direction of the 3D plane, then you be able to define your anisotropy. If this cross section is not what you're looking for (for example if you need to account for a finite xy plane) then I guess your problem can only be solved in 3D.
Song Changhwan
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Posted: 6 years ago Jun 18, 2018, 12:34 p.m. EDT

Well, I mean, when I use an anisotropic diamond, I have to set the thermal conductivity to anisotropy with 2D rectangle, then I want to know how to write the matrix. I need to put a value in C11 C22, but I do not know what is the cross-plane-direction, C11 or C22. What is the definition of the matrix component of anisotropy? If the thermal conductivity in the x-axis direction is in-plane, is it necessary to put in-plane thermal conductivity value in C11? I'm sorry to complicate the question.

Well, I mean, when I use an anisotropic diamond, I have to set the thermal conductivity to anisotropy with 2D rectangle, then I want to know how to write the matrix. I need to put a value in C11 C22, but I do not know what is the cross-plane-direction, C11 or C22. What is the definition of the matrix component of anisotropy? If the thermal conductivity in the x-axis direction is in-plane, is it necessary to put in-plane thermal conductivity value in C11? I'm sorry to complicate the question.

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