How to calculate force on tungsten/carbide

[larsencg]

Hello again,

I have some rough numbers for a bh curve and the permeability of tungsten/carbide/cobalt and now I am trying to figure out how to calculate the force exerted on a sample by an electromagnet. I have read some of the other posts here, but most seem to assume that the permeability of the core and the workpiece is high compared to the air gap. In my case, the permeability of the workpiece is not so high. It is almost 100x smaller than the core. It is attracted by the core but much more weakly than an ordianry piece of steel.

In this case, how does the workpiece properties enter into the force equation?

Thanks!!!

 

[israelkk]

You have to solve the magnetic circuits of the electromagnet coupled with the piece you want to pull. It can be done analytically using the techniques describes in the book Electromagnetic Devices, Roters, 1941 or using FEA.

http://israelkk.googlepages.com/home

 

[MagMike]

Hello larsencg,

Unfortunately, there is no simple analytical expression for calculating what you need. The force on tungsten/carbide/cobalt is heavily dependent on the magnetic response of the material to the magnetic field produced by the solenoid.

Even a ballpark estimation would be tough, it's a non-linear problem.

If you have the BH curve for the material (impressive!), it would be a pretty simple matter to model, especially if the system is rotationally symmetric. Check out the FAQ section for a list of magnetic modeling software. One of the freeware 2D/RS modelers should work for you.