Menu

Discussion Forum

New Discussion
Filtrer

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 The information provided may be out of date.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.

"Failed to find solution" Error in Structural Mechanics problem

Posted 17 août 2012, 10:35 UTC−4 Studies & Solvers, Structural Mechanics Version 4.3 2 Replies

Ricardo Aguilar
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi,

I keep running into a problem when I try to solve my model on COMSOL 4.3. The geometry is pretty simple, it's a rectangular piece of Polyethylene Naphtalate, with an array of hexagon cuts. The purpose of this study is to see if adding these cuts will affect the yield's strength of the material. The dimensions are as follows: 3mm by 1.5mm, with a thickness of 12.5 um. The forces that I've applied to the material are on opposite edges, applying equal but opposite forces. A third edge is left free, while the fourth edge I've applied a symmetry boundary condition to it. After meshing and clicking on solve, I get the following error:

Failed to find a solution.
The relative error (4.4e+002) is greater than the relative tolerance.
Returned solution is not converged.

I'm not sure what this exactly means, specially for such a simple study. I've attached the file.

Thanks in advance,
Ricardo Aguilar Jr.
2 Replies Last Post 7 mai 2015, 04:43 UTC−4
COMSOL Moderator

Hello Ricardo Aguilar

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Sumathi Ayyalusamy
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 7 mai 2015, 04:14 UTC−4
Hi
I am getting the similar problem ..stating the relative error is more than the tolerance.
\Please suggest if anybody found same problem and solved it.

Thanks in advance...

Sumathy A

Hi,

I keep running into a problem when I try to solve my model on COMSOL 4.3. The geometry is pretty simple, it's a rectangular piece of Polyethylene Naphtalate, with an array of hexagon cuts. The purpose of this study is to see if adding these cuts will affect the yield's strength of the material. The dimensions are as follows: 3mm by 1.5mm, with a thickness of 12.5 um. The forces that I've applied to the material are on opposite edges, applying equal but opposite forces. A third edge is left free, while the fourth edge I've applied a symmetry boundary condition to it. After meshing and clicking on solve, I get the following error:

Failed to find a solution.
The relative error (4.4e+002) is greater than the relative tolerance.
Returned solution is not converged.

I'm not sure what this exactly means, specially for such a simple study. I've attached the file.

Thanks in advance,
Ricardo Aguilar Jr.


Hi I am getting the similar problem ..stating the relative error is more than the tolerance. \Please suggest if anybody found same problem and solved it. Thanks in advance... Sumathy A [QUOTE] Hi, I keep running into a problem when I try to solve my model on COMSOL 4.3. The geometry is pretty simple, it's a rectangular piece of Polyethylene Naphtalate, with an array of hexagon cuts. The purpose of this study is to see if adding these cuts will affect the yield's strength of the material. The dimensions are as follows: 3mm by 1.5mm, with a thickness of 12.5 um. The forces that I've applied to the material are on opposite edges, applying equal but opposite forces. A third edge is left free, while the fourth edge I've applied a symmetry boundary condition to it. After meshing and clicking on solve, I get the following error: Failed to find a solution. The relative error (4.4e+002) is greater than the relative tolerance. Returned solution is not converged. I'm not sure what this exactly means, specially for such a simple study. I've attached the file. Thanks in advance, Ricardo Aguilar Jr. [/QUOTE]
Henrik Sönnerlind COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 7 mai 2015, 04:43 UTC−4
Hi,

The model attached to the original posting is singular because it does not have enough constraints. This is the most common reason for getting an error like this. A structural mechanics model must not possess any possible free rigid body movements in a stationary analysis.

The same error can however also appear of the problem has sufficient constraints, but is very ill-conditioned. It is then possible modify or completely switch of the error control in the linear equation solver in the study sequence (The Error section in the Direct node). Any results obtained after doing so must however be checked thoroughly.

Regards,
Henrik
Hi, The model attached to the original posting is singular because it does not have enough constraints. This is the most common reason for getting an error like this. A structural mechanics model must not possess any possible free rigid body movements in a stationary analysis. The same error can however also appear of the problem has sufficient constraints, but is very ill-conditioned. It is then possible modify or completely switch of the error control in the linear equation solver in the study sequence (The Error section in the Direct node). Any results obtained after doing so must however be checked thoroughly. Regards, Henrik

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