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 The information provided may be out of date.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.
I have a singular matrix error on MEF simulation
Posted 18 gen 2012, 10:03 GMT-5 Low-Frequency Electromagnetics Version 4.2a, Version 4.3, Version 4.3a 5 Replies
Please login with a confirmed email address before reporting spam
What is the problem in my simulation?
Attachments:
Please login with a confirmed email address before reporting spam
to check your mesh, create a second view (Definition View) and add a sub node "Hide Geometrical entity" and select the air entity "1" then click the rebuild, I would start meshing your copper in a finer way, then mesh the air as very coarse
Ideally you should use a round cable/wires, as on the sharp edges you have singularities, but it also works more or less like that
Then I would not "ground the full surface but just the second wire connector, or at most the lower plate
Finally for MEF to work, you must have some conductance in all materials otherwise you cannot resolve "V", try 1[S/m] for air it should do
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
I will try that.
Please login with a confirmed email address before reporting spam
and also, in MEF, do not forget all materials must have some conductivity (even 1S/m sould do)
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
It took me almost half of a work day just to find out that the "singular matrix error" is solely related to some materials in my setup having zero conductivity...
How am I supposed to know that materials inserted from the Comsol Material Library have to be _altered_ in order to make the simulation work in some cases!?
Why doesn't Comsol simply _validate_ the materials used in a simulation in order to give _meaningful_ error message?
A check for conductivity=0 when the mef module is used shouldn't be too complicated to be implemented....
Please login with a confirmed email address before reporting spam
its always our responsibility to check what we are doing. Anyhow this is a peculiarity of MEF, in MF a s=0 is OK. In fact in MEF too if you choose a "Domain Ampere law" node for the air.
It all depends on what you are modelling, and which hypothesis you need for a given physics, so there is no 1:1 way here
That is also why the training courses, or even the mini courses at the COMSOL conference are that useful, as they help you identify such simple traps, still remains the more subtle traps ;)
--
Good luck
Ivar