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 The information provided may be out of date.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.
Skull and Electrical Conductance
Posted Mar 4, 2013, 12:42 a.m. EST Low-Frequency Electromagnetics, Geometry, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.3 3 Replies
Please login with a confirmed email address before reporting spam
I'm just a beginner with Comsol and I'm trying to build a model of a human head that includes a top layer of skull, a brain, and space in between the two filled with some kind of conductive liquid.
The idea is to model and simulate how a point voltage source somewhere within the “brain” will affect the current flow on the surface of the head through the conductive materials. The issue I’m running into is how to create a point voltage source for one (if it’s even possible) as well as the ease of the geometries I’m using.
Currently, I’m using the basic idea of a 2 cm solid sphere (the “brain”) inside another solid 2.5 cm sphere, the 2.5 cm sphere is made up of conductive water, and an additional surface sphere with a 2.5 cm radius. I’m having trouble defining the material for the surface sphere (I’ll make it something like carbon).
So my two questions are, is there any advice for creating the geometries for such an endeavor and how does one create a point voltage source inside of a model?
Thanks for any help!
Additionally, when I run the study, I'm getting the error "Failed to find a solution - Singular matrix" There are xxx void equations. Returned solution is not converged.
- What does this mean systematically? Are one of my geometries not in contact correctly?
Please login with a confirmed email address before reporting spam
in the magnetic fields interface you can find the electrical dipole in the model builder according to the figure i attached.
The singular matrix is probably due to the fact that you tried solving the system without an exciation.
Bye
Eric
Attachments:
Please login with a confirmed email address before reporting spam
a 'point' voltage source would produce a singular field. Why not define something like a sufficiently small sphere and assign a potential BC to it. And you need a ground BC of course.
Cheers
Edgar
Please login with a confirmed email address before reporting spam
Though as far as i can remember current dipoles are used conventionally for human brain mapping, rather than voltage dipoles.