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 The information provided may be out of date.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.
Clarification regarding Jacobian error
Posted 04.02.2013, 06:24 GMT-5 Version 4.2, Version 4.2a, Version 4.3 2 Replies
Please login with a confirmed email address before reporting spam
While modelling a cantilever beam with two layers using Piezoelectric devices model, I had to choose two materials. One from the same physics, i.e. PZT 5 A and the second material from a different physics- the mems materials, Poly Silicon.
While computing, the following error was given " the feature eigen value solver 1(sol1/e1) - error failed to evaluate variable Jacobian ."
When I retried the same with the materials from the same physics, such an error didn't occur.
This problem comes only when we take materials from different physics.
Hence kindly let me know how this can be solved.
While computing, the following error was given " the feature eigen value solver 1(sol1/e1) - error failed to evaluate variable Jacobian ."
When I retried the same with the materials from the same physics, such an error didn't occur.
This problem comes only when we take materials from different physics.
Hence kindly let me know how this can be solved.
2 Replies Last Post 04.02.2013, 10:36 GMT-5
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi
could it be that some of the material parameters are T or pA dependent, and that neither T nor pA are defined ? or something similar. In doubt, create a Global Parameter T = 20[degC], pA = 1[atm] or what ever applies.
But it can be other parameters too ;)
--
Good luck
Ivar
could it be that some of the material parameters are T or pA dependent, and that neither T nor pA are defined ? or something similar. In doubt, create a Global Parameter T = 20[degC], pA = 1[atm] or what ever applies.
But it can be other parameters too ;)
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
I think Ivar is on the right track. In specific, it could be that after differentiation of a material model (which happens at the Jacobian computation), you end up with en expression that contains sqrt(-1) or division by zero or similar. Later versions of COMSOL have more specific error messages if you click "More" in the error message dialog box. So my advice is:
1) Update to the latest version 4.3a from www.comsol.com/support/download/
2) Use the More button and check the error log for details.
Niklas
1) Update to the latest version 4.3a from www.comsol.com/support/download/
2) Use the More button and check the error log for details.
Niklas