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biomedical and comsol
Posted 10 nov 2009, 00:13 GMT-5 2 Replies
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Hi there,
I am planning to use comsol for my project in which i have to simulate the forward problem of bioelectromagnetic.
Since i am new to this package, therefore, i have quite a few questions in my mind. I hope you would not mind answering these questions.
If i need to model a 3 or 4 layer spherical head model in comsol, which solver would be the best one, keeping in mind all layers are homogeneous and isotropic and i would be using quasi-static electromagnetic module.
How to define current dipoles within the spherical head model.
Which package would you recommend to import the medical images for 3d head modelling?
Thanks
Salman
I am planning to use comsol for my project in which i have to simulate the forward problem of bioelectromagnetic.
Since i am new to this package, therefore, i have quite a few questions in my mind. I hope you would not mind answering these questions.
If i need to model a 3 or 4 layer spherical head model in comsol, which solver would be the best one, keeping in mind all layers are homogeneous and isotropic and i would be using quasi-static electromagnetic module.
How to define current dipoles within the spherical head model.
Which package would you recommend to import the medical images for 3d head modelling?
Thanks
Salman
2 Replies Last Post 10 nov 2009, 03:20 GMT-5
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Posted:
2 decades ago
Hi
I can give a few advises to your question:
1) start in 2D until your model is behaving in a way you fully understand (as it computes rapidly), a "axisymmetric" 1/2 of a sphere could be a good starting point.
There are always two issue with symmetry, your geometrie is symmetric, and/or the BC (boundary conditions) are symmetric (or anti-symmetric). If both geometry and BC are symmetric you are lucky you can remain in simplified symmetry modelling, if not you will end up to do a full 3D model.
Note that you cannot copy/symmetry a mesh, as you can with a geometry (unfortunatey) one (false in my view) reason is that the mesh inherits its material ad BC properties from the surfaces it "belongs" to. For me it could still be handy to be able to make a symmetric mesh, perhaps by first generating the symmetric geometry but for that you must still write your own script code, what is fully possible.
finally with symmetry you might need to perform 2 calculations with symmetric and with anti-symmetric BC conditions. I do not have an example just like that in AC/DC but in structural for modal analysis, you need to repeat your calculations to get all modes, otherwise you forget 1 mode upon 2 !
for the solvers, I would le COMSOL choose and use its default, at least to start with.
for the 3D images (for me this would be a second step once a simple "speherical model" is running 80%, you should search some of the other discussions hereby, or try COMSOl support
Good luck
Ivar
I can give a few advises to your question:
1) start in 2D until your model is behaving in a way you fully understand (as it computes rapidly), a "axisymmetric" 1/2 of a sphere could be a good starting point.
There are always two issue with symmetry, your geometrie is symmetric, and/or the BC (boundary conditions) are symmetric (or anti-symmetric). If both geometry and BC are symmetric you are lucky you can remain in simplified symmetry modelling, if not you will end up to do a full 3D model.
Note that you cannot copy/symmetry a mesh, as you can with a geometry (unfortunatey) one (false in my view) reason is that the mesh inherits its material ad BC properties from the surfaces it "belongs" to. For me it could still be handy to be able to make a symmetric mesh, perhaps by first generating the symmetric geometry but for that you must still write your own script code, what is fully possible.
finally with symmetry you might need to perform 2 calculations with symmetric and with anti-symmetric BC conditions. I do not have an example just like that in AC/DC but in structural for modal analysis, you need to repeat your calculations to get all modes, otherwise you forget 1 mode upon 2 !
for the solvers, I would le COMSOL choose and use its default, at least to start with.
for the 3D images (for me this would be a second step once a simple "speherical model" is running 80%, you should search some of the other discussions hereby, or try COMSOl support
Good luck
Ivar
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Posted:
2 decades ago
To start with the geometry will be symmetric, as i intend to use spheres. However, if i introduce a current dipole at any arbitrary location within the inner most sphere the geometry itself becomes non-symmetrical (that’s my opinion).
On the other hand, my BC will be symmetric, so is it still possible to employ the symmetric approach?
Secondly and most importantly how it is possible to employ a current dipole. As this entity needs to be very small, comparatively speaking.
Is it possible to define one node as a positive source and the adjacent node as a negative sink in this scenario?
Once again Ivar, thank you for your support and help.
Salman
On the other hand, my BC will be symmetric, so is it still possible to employ the symmetric approach?
Secondly and most importantly how it is possible to employ a current dipole. As this entity needs to be very small, comparatively speaking.
Is it possible to define one node as a positive source and the adjacent node as a negative sink in this scenario?
Once again Ivar, thank you for your support and help.
Salman