Learning Forum

[ssaeidab]

Hi,

I want to model the B-H curve of a material. I have data for H(A/m) and B(T) as follows.

[Navya Chode]

.
The slope of the last two data points is used to extrapolate the BH curve. (While you are entering the BH data you might have observed the extrapolated green line on the right-side graph, while the data you entered will be below the green line in red)
Points Need to keep in mind while defining the BH curve.
┬ÀFor a Normal BH curve, the slope of the curve cannot be less than that of free space anywhere along the curve.
┬ÀThe value of B must increase along the curve.
┬ÀThe first data points for B and H must be 0 (zero).
┬ÀThe data points representing the BH curve should have enough points for an accurate representation of the curve.20 or more points should be specified with increased representation on the "knee" of the curve.
┬ÀSince BH operating points in the FEA solution may extend beyond the input BH data set, the BH data set is extrapolated in Maxwell.The slope of the last two user-defined data points is used to extrapolate the BH curve, and thus should be as close to mu0 as possible.
Regards Navya

[AndyJP]

Mega-Ampere per Watt ? What kind of spectral responsibility is that? Please, check your questions after posting. There is an "Edit" button for fixing typos.

[AndyJP]

>the slope of the curve cannot be less than that of free space
For "Intrinsic" it can be.

O.k. That's why once and once again I point it out is that calling the curve BH in "intrinsic" mode is unphysical. It is not BH, but MH (you can call it JH, but you have already reserved M_s for saturation magnetization, and J for current density, so it is MH, or 4¤ÇMH after all). Bi is a special term used by technologists in measurements, where you can not be sure about the actual M. so yes, they measure some kind of Bi... But Ansys EDT is a simulation suit, there is no place for notation used in measurements.

[AndyJP]

>The first data points for B and H must be 0 (zero).
which brings us to the fact that it is an "initial" BH curve, and not just a BH curve.

However, in Maxwell the first data point MAY begin from the coercive force, which tells the solver the complete BH shape by mirroring. The whole topic brings us to the fact that the setup is not very intuitive, explained mostly in rare presentations, and not manuals. It leaves questions; particularly for HFSS in weak magnetic fields in the area of hysteresis loop.

[ssaeidab]

Hi Thank you for letting me know. It is about 45KA/m.