Menu

Discussion Forum

New Discussion
Filter

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

How can I use the variables in solid mechanics module as an input without causing circular reference

Posted Apr 26, 2015, 9:20 p.m. EDT Studies & Solvers, Structural Mechanics Version 4.4 3 Replies

Rong Xu
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam


Hi,

Recently, I want to consider the pressure induced temperature increase in solid mechanics module. This temperature will cause the thermal expansion. So in the thermal expansion part, the temperature would be a function of the pressure solid.pm. However, if I add the pressure solid.pm in the T define(because solid.pm is an output variable in solid mechanics module), the Comsol will show:
Circular variable dependency detected.
- Variable: comp1.solid.Sl11
- Geometry: 1
- Domain: 1
- Feature: Time-Dependent Solver 1 (sol1/t1)

So I want to know how to solve this problem. In previous discussion, I found some people said we can use different solver methods like 'Iteration' to avoid this circular reference. Is it right? How can I change the solver method? Thanks so much
3 Replies Last Post May 25, 2015, 3:26 p.m. EDT
Nagi Elabbasi Facebook Reality Labs
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 10 years ago Apr 27, 2015, 6:56 p.m. EDT
You can create a Domain ODE/DAE, with a single variable, say PP that you assign equal to the pressure, solid.pm. Then in the temperature definition refer to PP instead of solid.pm.

Nagi Elabbasi
Veryst Engineering
You can create a Domain ODE/DAE, with a single variable, say PP that you assign equal to the pressure, solid.pm. Then in the temperature definition refer to PP instead of solid.pm. Nagi Elabbasi Veryst Engineering
Rong Xu
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 10 years ago Apr 27, 2015, 8:47 p.m. EDT
Hi,

Thanks for your advice. I think it would work well. I will try it right right!

Best,
Rong
Hi, Thanks for your advice. I think it would work well. I will try it right right! Best, Rong
Rong Xu
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago May 25, 2015, 3:26 p.m. EDT
Hi,

Last time you mentioned I can create a Domain ODE/DAE, with a single variable, say PP that you assign equal to the pressure, solid.pm. Now, in the Domain ODE/DAE, I set the source term as "PP-solid.pm" and set damping and mass coefficient as zero, as shown in Fig.
It seems there is a relatively large error between PP and solid.pm,especially at the boundary or interface. I am so confused about it. Did I miss something? Thanks!

Best,
Rong
Hi, Last time you mentioned I can create a Domain ODE/DAE, with a single variable, say PP that you assign equal to the pressure, solid.pm. Now, in the Domain ODE/DAE, I set the source term as "PP-solid.pm" and set damping and mass coefficient as zero, as shown in Fig. It seems there is a relatively large error between PP and solid.pm,especially at the boundary or interface. I am so confused about it. Did I miss something? Thanks! Best, Rong

Attachments:

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content