Quickfield vs Maxwell SV

Question

Quickfield vs Maxwell SV

cesaredu13 (Electrical)

(OP)

19 Aug 08 12:59

Hello everyone,

i am modeling a simple magnetic system with an U shaped yoke to pull an armature (see attached picture), i download quickfield and maxwell SV, i model the same geometry on both softwares, and i try to get the force exherted on the armature and i get different results, in quickfield i get a magnitude of .025N with an angle of 269 and with maxwell i get a magnitude of .039N with an angle of 270.5.
I already check and i have the same material properties and the same geometry dimensions and the same current density on the current carrying cable.

Am i missing something ? Boundary conditions maybe.

I know that quickfield calculate the integrals over 1 meter in the z direction, is the same thing for Maxwell SV ?

can this depth number be modified in Maxwell SV ?

If the software calculates 1N of force on the armature and is calculated over 1 meter in z direction it means if a wan to know the force if i had 50 cm depth in the z direction the force will be the half thats 1N/2= .5N ?

Any idea where i can find more info on understanding 2d FEA ?

Thanks in advanced ??

BobM3 (Mechanical) · Answer 1 · 2008-08-19 13:30:17

I use Quickfied. You are right in that you have to multiply the force number it gives you (actually force/depth) by the actual depth of your device. I would assume Maxwell (if it's a 2d program) would require a similar step.

Try running a textbook (easy model and known answer) problem in each to figure out what is going on.

dgallup (Automotive) · Answer 2 · 2008-08-21 09:49:11

Do both solutions assume infinite length? I would expect them to in a 2D solution but in the real world you will have fringing on each end. One solution may try to approximate the fringing. I don't use either program so I don't know any details on their solvers.

cesaredu13 (Electrical) · Answer 3 · 2008-08-21 13:10:05

On quickfield you can define the length, in this case is 1 meter, on maxwell i dont know , i am guessing that is also 1 meter .

but i have another question, how will fringing affect the force exherted over the armature ?

what i think is that fringing will reduce the efective magnetic field on the armature reducing also the force, is this correct ?

Thanks

Bilbrough (Materials) · Answer 4 · 2008-08-26 11:06:09

Force calculations are notoriously finicky in FEM. Make sure you have a very dense mesh before running this result then, to be sure, double the mesh and run it again comparing the results to the first time. If the results are significantly different then your solution is not converged and your results are no good. Keep bumping up mesh density until you get a converged solution.

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Quickfield vs Maxwell SV