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Adding thermal expansion

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Hi,

I would like to add some simple thermal epansion to my model, however I do not have the thermal expansion part of the solid mechanics module... Is there a way to add it via the mathematics module?

Ideas and examples would be highly appriciated!

Thanks,

Tsvetoslav

14 Replies Last Post Jun 23, 2017, 10:45 a.m. EDT

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Posted: 1 decade ago Oct 10, 2013, 4:41 a.m. EDT
Hi,


Try if this works first...

I presume you have at least basic structural mechanics in which you can solve linear elasticity.

In that case, go directly to "equation view" under "solid mechanics > linear elastic material model" and then scroll down to the following variables:

solid.Sl11, Sl22 and Sl33 (diagonal components of stress tensor)

At the end of these 3 existing equations just append the following:

-3*thermal_coeff*(T-Tref)*Bulk_modulus

The variables are self explanatory.


Suresh
Hi, Try if this works first... I presume you have at least basic structural mechanics in which you can solve linear elasticity. In that case, go directly to "equation view" under "solid mechanics > linear elastic material model" and then scroll down to the following variables: solid.Sl11, Sl22 and Sl33 (diagonal components of stress tensor) At the end of these 3 existing equations just append the following: -3*thermal_coeff*(T-Tref)*Bulk_modulus The variables are self explanatory. Suresh

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Posted: 1 decade ago Oct 17, 2013, 9:25 a.m. EDT
Hi Suresh,

Thank you very much! I am away from my computer (with the COMSOL license) these days but I will try out what you suggested in the coming weeks and come back to you.

Thanks again and speak to you soon.

Best wishes,

Tsveti
Hi Suresh, Thank you very much! I am away from my computer (with the COMSOL license) these days but I will try out what you suggested in the coming weeks and come back to you. Thanks again and speak to you soon. Best wishes, Tsveti

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Posted: 1 decade ago Nov 19, 2013, 10:07 a.m. EST
Hello Tsvetoslav,

I am also very interested by this tip.
Have you succeed to integer thermal stress in the solid mechanic module ?

Julien
Hello Tsvetoslav, I am also very interested by this tip. Have you succeed to integer thermal stress in the solid mechanic module ? Julien

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Posted: 9 years ago Apr 28, 2015, 6:20 a.m. EDT
Hello everybody,

i have the same problem as above described. I want to model a coupling between strain and temperature distribution in a geothermal heat transfer where the fluid is injected through a sphere. My results are a bit confusing. I get a temperature distribution as implemented, but I get no strain distribution.
Attached you can find my model. Have I forgotten something? I can't understand the previous suggested solution.

In general I want to model thermoelastic processes. Is this the exact concept or thought at all?

Thank you and Cheers

Nastasja
Hello everybody, i have the same problem as above described. I want to model a coupling between strain and temperature distribution in a geothermal heat transfer where the fluid is injected through a sphere. My results are a bit confusing. I get a temperature distribution as implemented, but I get no strain distribution. Attached you can find my model. Have I forgotten something? I can't understand the previous suggested solution. In general I want to model thermoelastic processes. Is this the exact concept or thought at all? Thank you and Cheers Nastasja


Jeff Hiller COMSOL Employee

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Posted: 9 years ago Apr 28, 2015, 8:56 a.m. EDT
Hello Nastasja,
The screenshot you sent shows the GUI in German, which is fine but you may get more feedback on your work from other users of the Discussion Forum if you posted your mph file: this way other users would be able to switch the model to whatever language they prefer.
Best,
Jeff
Hello Nastasja, The screenshot you sent shows the GUI in German, which is fine but you may get more feedback on your work from other users of the Discussion Forum if you posted your mph file: this way other users would be able to switch the model to whatever language they prefer. Best, Jeff

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Posted: 9 years ago Apr 29, 2015, 6:05 a.m. EDT
Hey Jeff,
I can't attach my file because the size is too big. Is there a possibility to attach the file in another way?

Cheers

Nastasja
Hey Jeff, I can't attach my file because the size is too big. Is there a possibility to attach the file in another way? Cheers Nastasja

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Posted: 8 years ago Feb 1, 2016, 12:28 p.m. EST
Hi,

Could you please explain me about the negative sign and the coefficient 3.?

Thank you

--
Bhagya
Hi, Could you please explain me about the negative sign and the coefficient 3.? Thank you -- Bhagya

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Posted: 8 years ago Jun 7, 2016, 4:30 p.m. EDT
Hi,

I would like to add the thermal expansion coefficient to the Busbar geometry. Could you thus specify on how to go about the same; also working on basic structural mechanics module. Thanks a lot for any inputs/ideas.

Regards,
Chida.
Hi, I would like to add the thermal expansion coefficient to the Busbar geometry. Could you thus specify on how to go about the same; also working on basic structural mechanics module. Thanks a lot for any inputs/ideas. Regards, Chida.

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Posted: 8 years ago Jul 11, 2016, 5:21 p.m. EDT
Chidanand,
Did you figure this out? I can't seem to get it.

Bryan
Chidanand, Did you figure this out? I can't seem to get it. Bryan

Walter Frei COMSOL Employee

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Posted: 8 years ago Jul 12, 2016, 10:02 a.m. EDT
Hello,

To address the original question, about adding thermal expansion using the core capabilities of COMSOL Multiphysics, please see this Application Example:
www.comsol.com/model/thermal-microactuator-simplified-16357
This example uses the physics interfaces from the base package of COMSOL Multiphysics, and then manipulates them using the Equation View feature.

Best Regards,
Hello, To address the original question, about adding thermal expansion using the core capabilities of COMSOL Multiphysics, please see this Application Example: https://www.comsol.com/model/thermal-microactuator-simplified-16357 This example uses the physics interfaces from the base package of COMSOL Multiphysics, and then manipulates them using the Equation View feature. Best Regards,

Jeff Hiller COMSOL Employee

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Posted: 8 years ago Jul 13, 2016, 9:45 a.m. EDT
To remove any ambiguity:

- If your license includes either the Structural Mechanics Module or the MEMS Module, there is no need to edit any equation to include thermal expansion in a model. Instead, simply right-click on the "Linear elastic material" node in the model tree, and scroll down to "Thermal expansion".

- Some of the early posts in this thread suggest there is a bit of confusion going on between the basic structural mechanics capabilities included in the COMSOL Multiphysics core package on the one hand vs the much more extensive capabilities of the Structural Mechanics Module on the other hand. You can find the long list of capabilities for mechanical analysis that the Structural Mechanics Module adds to the core package, such as thermal expansion, shells, beams, membranes, plates, trusses, magnetostriction, piezoelectric materials, large deformations, hygroscopic swelling, the ability to connect with the Nonlinear Structural Materials Module or the Fatigue Module or the Multibody Dynamics Module, and many more, at this link:
www.comsol.com/products/specifications/structural-mechanics/

Unsure what modules are and are not included on your license? The Model Wizard is not where you find that information. Instead look under File > Licensed and Used Products.

Best,
Jeff
To remove any ambiguity: - If your license includes either the Structural Mechanics Module or the MEMS Module, there is no need to edit any equation to include thermal expansion in a model. Instead, simply right-click on the "Linear elastic material" node in the model tree, and scroll down to "Thermal expansion". - Some of the early posts in this thread suggest there is a bit of confusion going on between the basic structural mechanics capabilities included in the COMSOL Multiphysics core package on the one hand vs the much more extensive capabilities of the Structural Mechanics Module on the other hand. You can find the long list of capabilities for mechanical analysis that the Structural Mechanics Module adds to the core package, such as thermal expansion, shells, beams, membranes, plates, trusses, magnetostriction, piezoelectric materials, large deformations, hygroscopic swelling, the ability to connect with the Nonlinear Structural Materials Module or the Fatigue Module or the Multibody Dynamics Module, and many more, at this link: https://www.comsol.com/products/specifications/structural-mechanics/ Unsure what modules are and are not included on your license? The Model Wizard is not where you find that information. Instead look under File > Licensed and Used Products. Best, Jeff

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Posted: 8 years ago Jul 13, 2016, 9:48 p.m. EDT
Hi Walter,

I do not see any modified equation in "linear elastic material" section. it is just stationary equations. Am I missing something? By the way, I see "linear elastic material" kind of locked. what does it mean?




Hello,

To address the original question, about adding thermal expansion using the core capabilities of COMSOL Multiphysics, please see this Application Example:
www.comsol.com/model/thermal-microactuator-simplified-16357
This example uses the physics interfaces from the base package of COMSOL Multiphysics, and then manipulates them using the Equation View feature.

Best Regards,


Hi Walter, I do not see any modified equation in "linear elastic material" section. it is just stationary equations. Am I missing something? By the way, I see "linear elastic material" kind of locked. what does it mean? [QUOTE] Hello, To address the original question, about adding thermal expansion using the core capabilities of COMSOL Multiphysics, please see this Application Example: https://www.comsol.com/model/thermal-microactuator-simplified-16357 This example uses the physics interfaces from the base package of COMSOL Multiphysics, and then manipulates them using the Equation View feature. Best Regards, [/QUOTE]


Henrik Sönnerlind COMSOL Employee

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Posted: 8 years ago Jul 14, 2016, 2:44 a.m. EDT
Hi Adnan,

You have to make Equation View visible.

A screenshot of how to do that can for example be found (just below the second animation) in

www.comsol.com/blogs/how-to-make-boundary-conditions-conditional-in-your-simulation/

The 'padlock' symbol which you see indicates that the equations in that node have been edited manually.

Regards,
Henrik

Hi Adnan, You have to make Equation View visible. A screenshot of how to do that can for example be found (just below the second animation) in https://www.comsol.com/blogs/how-to-make-boundary-conditions-conditional-in-your-simulation/ The 'padlock' symbol which you see indicates that the equations in that node have been edited manually. Regards, Henrik

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Posted: 7 years ago Jun 23, 2017, 10:45 a.m. EDT
Hi henrik
I'd like to do a research of temperature effect on guided wave propagation, i'd like to see with different temperature, the variation of echos of guided wave, so i build a model with 2 mods "solid mechanical" and "heat transfert in solid", but it counts the thermal heat, which i don't want, i prefer a constant enviromental temperature.
So, do you have some solutions?
Best Wishes
Huang Pengtao
Hi henrik I'd like to do a research of temperature effect on guided wave propagation, i'd like to see with different temperature, the variation of echos of guided wave, so i build a model with 2 mods "solid mechanical" and "heat transfert in solid", but it counts the thermal heat, which i don't want, i prefer a constant enviromental temperature. So, do you have some solutions? Best Wishes Huang Pengtao

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