Ansys Maxwell -- How do I add a permanent magnet into my simulation?

[simakz2010]

hi all
I am going to do a project in ansys maxwel, actually i need to add a magnet and i know i have to do it with add material. my magnet is NdFeB . i give the material from net, actually i can not valid them because they are different in value. I need to calculate Mu(permeability ) and I nedd exact value for Hc and Br for this magnet. is there anybody here knew about that or use this magnet before? is it linear or none linear in practice? i will appreaciate any kind of response

 

[essenmein]

NdFeB is a common neodymium magnet composition, they come in a number of variants. I would pick a material and then hit google and find a manufacturer data sheet, this will give you the BH curve that you can enter into the material properties.

Generally magnetic materials are not linear, they all saturate or demagnetize given the right situation, although for some small signal analysis linearity can be assume without too much loss of accuracy.

Maxwell will handle both linear and non linear (ie BH curve) magnetic properties.

Then there are several ways you can do permanent magnet things in maxwell, fundamentally H field created by permanent magnet is no different from H field created by flowing current, (the only thing that can make magnetic field is moving charge, which is how both work), so in models depending on how much data you have available, how much time you have and what you are trying to achieve there are a few ways of creating the effect of a PM in your simulation, current in conductor, linear Hc/Br or BH curve, also fairly sure you can just set a B or H field as an excitation, but I have not tried that.

 

[simakz2010]

it is very very kind of you if you could give me the link for B-H curve of that .

 

[essenmein]

it is very very kind of you if you could give me the link for B-H curve of that .

Basically I'm not going to do that for two reasons, 1) I have no idea what material you might actually want, 2) This information is readily available on the internet, including actually the question you asked above, so in my opinion a good skill set to have in general is being able to use google to find what you want.

I'll give you a hint though, for me at least, the second/third/fourth/fifth link google provides when simply searching "NdFeB" provide a lot of back ground into on how to use permanent magnets as well as all the material data you could want.

 

[simakz2010]

thank you very much. yes you are right.
firstly,what i going to use in my model in ansys maxwell, ( because i have an interval value for Hcb and Br for my permenant magnet), i calculate mu respect to :
mu*m0=Br/Hcb . and I put average of Br and Hcb insteade of any value without purpose.

secondly, because I knew that the magnet I use is for sure nonlinear, i could not set anything related to that.

I want to know your opinion about the first part and also my pleasure to have your suggestion for second part

 

[essenmein]

When you view/edit materials you get a list, relative permeability, bulk conductivity etc. For relative permeability change the "type" from "simple" to "nonlinear", and the "value" column should now prompt you for BH curve. Entering a BH curve will need you to have a good understanding of magnetic material properties, eg you'll have to select between intrinsic and normal BH curve data, and translate the demag (2nd quadrant BH curve) to the 1st quadrant, this is done by adding a constant H shift.

Incidentally Maxwell has NdFe30 and NdFe35 as standard material properties, however the relative permeability is of the simple variety.