Anisotropic heat expansion coefficient in ElmerGUI

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thomasatelmer
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Anisotropic heat expansion coefficient in ElmerGUI

Post by thomasatelmer »

Hello alltogether,

this time I am hitting with a fairly simple question - so simple that I cannot believe that it has not been asked and answered before. But one and a half hour of heating google's servers did not provide me any hints. So sorry if this is a dull question ;)

I am trying to model an anisotropic material behaviour in thermal expansion for modeling an PC board, which expands more in direction of thickness than in lateral dimensions. I found actually the possibility to define the heat expansion coefficient in the SIF file as

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Heat expansion Coefficient(3) = 0.001 0.001 0.01
by overwriting the definition in the raw SIF after saving the project.

However, I would like to enter the material info the egmaterials.xml, but there the format is different:

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<parameter name="Heat expansion coeff." >3.43e-3</parameter>

and all guesses as to how it can be set separate for each axis have not been to Elmer's satisfaction... Can anyone give me a hint how to get this?

And if it is really possible, the next question that would torture me would be if the scheme

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Variable Temperature; 273.0 xxx.x; 323.0 yyy.y ; End
would also be possible for different axis' ?

I appreciate your targeted feedback,
Thank you! Thomas.
raback
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Re: Anisotropic heat expansion coefficient in ElmerGUI

Post by raback »

Hi

You could use a syntax not affecting the left-hand-side:

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Heat expansion Coefficient = Size 3; 0.001 0.001 0.01
I don't think this is easily extandable for being dependent on other stuff. User defined function might be needed. Check these tests for guidance:
elmeruser@elmeruser-VirtualBox:~/elmerfem/fem/tests$ ls | grep HeatUniso
HeatUniso
HeatUnisoMATC
HeatUnisoTable
HeatUnisoUDF
-Peter
thomasatelmer
Posts: 38
Joined: 18 Jan 2019, 18:18
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Re: Anisotropic heat expansion coefficient in ElmerGUI

Post by thomasatelmer »

Thank you Peter for answering this - I shall try to use the proposed nomenclature in the xml snippet for the respective material. As to my second question - well, I was afraid that would be the answer. But anyhow, just another reason to learn about UDFs :-).

Regards and keep up the good work and support,
Thomas.
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