Discussion Forum

Hello all,

This is my first time using COMSOL, (I used MATLAB to check my model) and for a research project's requirements, I need to create the 3D model of the following as soon as possible, however could not manage to do it.

Model is pretty basic: I have a beam, with one end fixed. On the top of it, there will be a neodymium magnet attached, and right under the magnet, there is going to be a coil. By applying an AC current to the coil, I would like to calculate the deflection at the tip of the beam.

What I have done:

I created the beam, with the required material
Applied a tetrahedral mesh, and did an eigenfrequency study to check whether the resonance frequency is OK with my MATLAB calculations.
Created a cylindrical goemetry, and formed an union with the beam.
Then added a new material for the Neodymium magnet.
Added its density, Young's modulus, Poisson's ratio, and relative permeability. However it keeps asking me for its relative permittivity and electrical conductivity. From what I saw from forum posts, and sample models, it seems like it should not be obligatory?

From now on, I am kind of confused on what to do:

As a beginning, I do not want to model the coil. I would like to apply a magnetic field, and observe the beam's deflection.
I checked the forums, and sample model's, and noticed that I needed an air box.
I created a big rectangle, and hopefully successfully filled it with air.
Now my second problem is: I see that, many people are using moving meshes on projects that are related to mine and I think I need to use that too. Do I need to use it?
Third problem: Under magnetic fields, I selected magnetic box's edges as my boundaries, and specified a dummy magnetic field. (Did not specify anything else, should I?) Now when I do a frequency domain study, I cannot see any deflection. I am not sure whether it is because I cannot apply the magnetic field correctly, or something is wrong with the magnet, etc. Do you have any ideas?

I am quite new and do not have an idea on what to do and since the time is limited, I really need your help. If you can describe what I need to do, I will be grateful.


You can find the project file attached,
Best,
Allen