Virtual Force

To compute the virtual force on an object, the system uses the principle of virtual work. In the structure shown below, the force on the plate in the direction of the displacement, s, is given by the following relationship:

where W(s,i) is the magnetic coenergy of the system. The current, i, is held constant.

Unlike the classical virtual work method, the plate is not actually moved during the force computation. Instead, only the tetrahedra that lie along the outside surface of the object are virtually distorted. Thus, the force computation only requires one field solution.