Discussion Forum

Posted: 1 decade ago 10.10.2013, 04:41 GMT-4

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

Posted: 1 decade ago 17.10.2013, 09:25 GMT-4

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

Posted: 1 decade ago 19.11.2013, 10:07 GMT-5

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

Posted: 10 years ago 28.04.2015, 06:20 GMT-4

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

Attachments:

• screenshot.png

Posted: 10 years ago 28.04.2015, 08:56 GMT-4

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

Posted: 10 years ago 29.04.2015, 06:05 GMT-4

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

Posted: 9 years ago 01.02.2016, 12:28 GMT-5

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

Posted: 8 years ago 07.06.2016, 16:30 GMT-4

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.

Posted: 8 years ago 11.07.2016, 17:21 GMT-4

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

Posted: 8 years ago 12.07.2016, 10:02 GMT-4

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,

Posted: 8 years ago 13.07.2016, 09:45 GMT-4

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

Posted: 8 years ago 13.07.2016, 21:48 GMT-4

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]

Attachments:

• Thermal expansion.JPG

Posted: 8 years ago 14.07.2016, 02:44 GMT-4

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

Posted: 7 years ago 23.06.2017, 10:45 GMT-4

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