Consideration of the spatial orientation of magnetic field quantities and tensile mechanical stress in the Finite Element Analysis of electrical machines

Due to speed-dependent centrifugal forces, the support of the torque, static mechanical stress introduced by manufacturing processes the laminated core of rotating electrical machines is exposed to considerable mechanical stress. The resulting stress distribution changes the magnetic properties of the electrical steel. To take this into account, a magnetization model is constituted on the basis of vector magneto-mechanical measurements that include the magnetic permeability as a function of the mechanical stress and the angle between magnetization - and the maximum principal stress direction. Subsequently, the model is integrated into the finite element simulation of a permanent magnet excited synchronous machine at different rotational speeds.