March 18, 2020 at 11:59 am
SAKLNT
Subscriber

Aim: To calculate the force on plunger for different Flux densities/ strength of the magnet

Background: We have a relay as per attached image. Alnico 5 is used a permanent magnet. We initially magnetize Alnico 5 till saturation and will measure the force on plunger manually. Then a controlled demagnetization pulse is given and the plunger force is measured again. This is repeated till the desired plunger force is obtained. So i need to model this problem in Ansys and simulate the force for different magnetic strengths.

Data available with me:

1. Demagnetization curve ( B-H curve of Alnico 5 in 2nd quadrant taken from Ansys library)  There are two ways of specifying magnetic parameters.

2. Mild steel magnetic properties.

My understanding:

Method 1:  B-H curve ( in second quadrant) for a permanent magnet + Magnetic coercivity (magnitude and direction)

    In this case, B-H curve of a particular magnet is available which will be fed as tabulated data. Magnetic coercivity is taken from B-H curve and only the direction is variable.

Method 2 :   Magnetic coercivity ( magnitude and direction) + Isotropic relative permeability

     In this case, magnitude of Magnetic coercivity of a particular material is constant( I dont understand why this is kept variable) and need to specify the relative permeability of the material ( I dont know how to get the permeability from B-H curve).

 

I am using Alnico 5 material as permanent magnet. Initially , Alnico 5 will be magnetically saturated. This Alnico 5 will be demagnetized step by step . I need to find the force on the plunger for each value of B in the curve ( Image attached for reference).

Now if I follow method 1, both B-H curve and magnetic coercivity of the material is fixed/constant and only the magnetization direction is variable. In this case how will I be able to check for different flux densities of the magnet? 

If I follow method 2, I can vary Magnetic coercivity ( magnitude and direction) as well as Permeability. Ideally magnitude of magnetic coercivity is constant for a particular material ( How this will be a variable). Also how to get the permeability for different flux densities.

Kindly help me in identifying the right method and how to give input parameters in the suggested method.

 

Regards