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material property setting?

Posted 15.12.2011, 13:36 GMT-5 Materials Version 4.2, Version 4.2a 4 Replies

Luyao Xu
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Hi,

I want to customized set the material's property in a 2D model. the material property is a function of position (coordinate-dependent).

e.g.

the conductivity in a 2D model changed through x-direction:

conductivity=f(x), x is the x-coordinate.


How to do that in comsol 4.2?

is there any example in model library?


Thank you very much



4 Replies Last Post 24.02.2014, 12:55 GMT-5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 15.12.2011, 15:17 GMT-5
Hi

try it out, take a simple case i.e with a cylinder in 2D-axi, define a material conductivity as "sigma(z)" or for example:

sigma0 + sigma_slope * ( z - z0 ) / ( Ztop - Zbottom )

(since the axis in 2d-axi is along Z this should vary the conductivity along the axis), apply a constant current and check the voltage

here z0 is the starting point for z calculation, Ztop and Zbottom the Z coordinates of the cylinder top and bottom, hence the difference is the cylinder length

I believe this should work like that, I cannot check as I'm not now in front of my COMSOL WS ;)

--
Good luck
Ivar
Hi try it out, take a simple case i.e with a cylinder in 2D-axi, define a material conductivity as "sigma(z)" or for example: sigma0 + sigma_slope * ( z - z0 ) / ( Ztop - Zbottom ) (since the axis in 2d-axi is along Z this should vary the conductivity along the axis), apply a constant current and check the voltage here z0 is the starting point for z calculation, Ztop and Zbottom the Z coordinates of the cylinder top and bottom, hence the difference is the cylinder length I believe this should work like that, I cannot check as I'm not now in front of my COMSOL WS ;) -- Good luck Ivar
Luyao Xu
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Posted: 1 decade ago 15.12.2011, 16:16 GMT-5
It works, Thanks a million!!!
It works, Thanks a million!!!
Amir Najibi
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Posted: 1 decade ago 17.04.2012, 08:02 GMT-4
Hi Ivar.
I want to model a material which its properties are varying according to the spatial coordinates (x, y, z). The material has temperature dependent properties. In COMSOL 4.2 how can I do this task? I am new in COMSOL and I need the detailed comments.
Regards.
Hi Ivar. I want to model a material which its properties are varying according to the spatial coordinates (x, y, z). The material has temperature dependent properties. In COMSOL 4.2 how can I do this task? I am new in COMSOL and I need the detailed comments. Regards.
Edoardo Rubino
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Posted: 1 decade ago 24.02.2014, 12:55 GMT-5
Hello,

I have the same problem but I can't fix it by using the same procedure.

I have a 2D rectangle and I want to change the thermal conductivity along the x axis as a function of x.

I changed the predefined thermal conductivity with both expressions: "k(x)" and "k0+k_slope*(x-x0)/(xinitial-xfinal)". when I used the second one I also defined in Model->Definitions k0, k_slope, xinitial and xfinal but it doesn't work.

Am I missing something? Do I have to define anything else?

Thank you very much for your help,

Edoardo
Hello, I have the same problem but I can't fix it by using the same procedure. I have a 2D rectangle and I want to change the thermal conductivity along the x axis as a function of x. I changed the predefined thermal conductivity with both expressions: "k(x)" and "k0+k_slope*(x-x0)/(xinitial-xfinal)". when I used the second one I also defined in Model->Definitions k0, k_slope, xinitial and xfinal but it doesn't work. Am I missing something? Do I have to define anything else? Thank you very much for your help, Edoardo

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