An original stationary method using local jacobian derivative for direct finite element computation of electromagnetic force, torque and stiffness

Abstract

For the direct computation of total force or torque in saturable magnetic field problems, the virtual-work principle is applicable. A finite element implementation of the virtual-work principle using the method of local jacobian derivative is proposed. A direct way to compute stiffness is also given. This new method is an extension of the virtual-work principle and is based on both the stationary method and the local jacobian derivative one. For each position of the movable body, the methods need only one field computation for either linear or nonlinear problems. These methods seem to be very attractive because they are accurate, cheap and easy to implement. They have been successfully used in two-dimensional and also three-dimensional finite element packages, using either magnetic scalar vector potentials. © 1982.