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Force calculation between a multi-turn coil and a permanent magnet

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Hello,

I'm trying to simulate the force between a multi-turn coil and a permanent magnet.
The magnet is inside of the coil. It has to move against a flexure to reach its resting position.
Therefore i want to know the force with which the coil is able to move the magnet.
I thought i can get the force in dependence of the distance to between the coil and magnet.
But i only get the force of the coil and it is not changing with the increasing distance (implemented by a moving mesh) of the magnet.
Can someone give me a hint? Is it a practical way to simulate the increasing distance between the coil and the magnet with a moving mesh?

Thank you!

Jan


3 Replies Last Post 24 sept. 2015, 03:51 UTC−4
Nirmal Paudel COMSOL Employee

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Posted: 9 years ago 18 sept. 2015, 09:19 UTC−4
Hi,

To calculate the force on the magnet, you would need to add a "Force Calculation" feature which will compute the Maxwell stress tensor on the magnet. But, note that the moving mesh physics should be applied only one the sliding region. For this, you would need to finalize the Geometry with Form Assembly, which will automatically create an identity pair between the stationary and sliding domains. Make sure that this identity pair boundary is not touching the Magnet boundaries where you have a Force Calculation feature assigned. The computed force on identity pair boundaries will be inaccurate. See the attached model which demonstrate this.

Hope this will be useful.

Best Regards,
Nirmal Paudel
Hi, To calculate the force on the magnet, you would need to add a "Force Calculation" feature which will compute the Maxwell stress tensor on the magnet. But, note that the moving mesh physics should be applied only one the sliding region. For this, you would need to finalize the Geometry with Form Assembly, which will automatically create an identity pair between the stationary and sliding domains. Make sure that this identity pair boundary is not touching the Magnet boundaries where you have a Force Calculation feature assigned. The computed force on identity pair boundaries will be inaccurate. See the attached model which demonstrate this. Hope this will be useful. Best Regards, Nirmal Paudel


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Posted: 9 years ago 18 sept. 2015, 11:25 UTC−4
Hello Mr. Paudel,

thank you for your help. This will help me a lot!

Best Regards,

Jan
Hello Mr. Paudel, thank you for your help. This will help me a lot! Best Regards, Jan

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Posted: 9 years ago 24 sept. 2015, 03:51 UTC−4
Hello,

i now have a model, where the permanent magnet increasis its distance to the coil.
But the force of the magnet is increasing. as far as i know it shoul decrease, or am i wrong?
Can someone help me with this issue?

thank you and kind regars
Jan
Hello, i now have a model, where the permanent magnet increasis its distance to the coil. But the force of the magnet is increasing. as far as i know it shoul decrease, or am i wrong? Can someone help me with this issue? thank you and kind regars Jan

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