Continuous Local Material Model for Cut Edge Effects in Soft Magnetic Materials

Shape-giving production steps in the manufacturing of electrical machines often introduce plastic deformation and residual stress into the soft magnetic material, thus decreasing the magnetic quality and locally increasing both the static and dynamic hysteresis losses near the cut edges. Different models have been published, aiming to describe the changing local magnetization and loss behavior. Current approaches often consider permeability deteriorations by subdividing the soft magnetic material into the slices of different material properties. Three cut edge models are discussed here, where two describe the changed local polarization and the third estimates the resulting global iron losses. This paper presents a continuous material model for an efficient numerical model of the local magnetization. By replacing effortful sliced models, the continuous model is independent of the discretization and converges in the case of coarse meshes to the sliced model.