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Optimization Electromagnetic Device

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Hello!

I need help for an electromagnetic problem- a solenoid who has one main coil and another 2 correcting coils.
I want to optimize the length of the 2 correcting coils and the distance between them, so that the magnetic field be as uniform as possible.
The objective function is f(S,L)=(Bmax-Bmin)/2, where Bmax and Bmin are maximum and minimum of magnetic induction within the controlled subregion and B0 is the induction at the centre of the compound solenoid.
And I need to find the minimum f(S,L).
No constrains are imposed on the latter except the fact that S,L must be positive.

How do I putt that constrains or the objective function in Comsol?

Please help!


3 Replies Last Post 2010年7月12日 GMT-4 04:25

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Posted: 1 decade ago 2010年7月8日 GMT-4 03:01
Hi ,

I am not sure what is the problem but I think you need to have physic node next to optimization node, included as well. Additionally I would use deformed mesh to if you are running V3.5 but if you have V4.0 I heard (thou not yet tried) the geometry optimization is possible simply by creating geometry with variables (instead of the number you can say that your rectangle is variable rect_a which you can use after in you optimization.)

KR
Nenad
Hi , I am not sure what is the problem but I think you need to have physic node next to optimization node, included as well. Additionally I would use deformed mesh to if you are running V3.5 but if you have V4.0 I heard (thou not yet tried) the geometry optimization is possible simply by creating geometry with variables (instead of the number you can say that your rectangle is variable rect_a which you can use after in you optimization.) KR Nenad

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 2010年7月10日 GMT-4 09:50
Hi

I believe first you might restrain your model to the first quadrant and use a horizontal "antisymmetry" boundary on Y=0. It will speed up the calculations.

Then you need to solve the B value, so either you set up a full FEM model with an "air" interface (quarter of circle), perhaps add a spherical PML (perfectly matched layer) and integrate your B value to get a nice optimisation error function, or you add just the equations and solve the B value as 1D PDE case along Z.

In V4 you can also define the position of the coil as a variable, and have COMSOL reconstruct the geometry as it solves.

hope this helps
Good luck
Ivar
Hi I believe first you might restrain your model to the first quadrant and use a horizontal "antisymmetry" boundary on Y=0. It will speed up the calculations. Then you need to solve the B value, so either you set up a full FEM model with an "air" interface (quarter of circle), perhaps add a spherical PML (perfectly matched layer) and integrate your B value to get a nice optimisation error function, or you add just the equations and solve the B value as 1D PDE case along Z. In V4 you can also define the position of the coil as a variable, and have COMSOL reconstruct the geometry as it solves. hope this helps Good luck Ivar

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Posted: 1 decade ago 2010年7月12日 GMT-4 04:25
Thanks a lot!
Thanks a lot!

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