Stress analysis of motor cores based on the measurement of magnetostriction of non-oriented silicon steel sheet

In order to control and reduce the electromagnetic vibration of motors, the stresses in motor cores, which are the inherent reasons of vibration, should be computed accurately. Electromagnetic stresses in motor cores are mainly generated from magnetostrictive effect of silicon steel and Maxwell electromagnetic force between the stator and the rotor. So far, stress analysis on motor cores, which is based on the finite element numerical method, did not consider the influence of stress on magnetostrictive and magnetic properties of the core material. Thus, this paper first measures multi-group magnetostrictive and magnetic characteristic curves of non-oriented silicon steel sheet under different stresses to support the computation. Then an electromagneto-mechanical coupled numerical model for motors considering anisotropy and the influence of stress on magnetic properties of the core material is proposed and stress distribution of motor cores is calculated. From the computed results, it can be seen that radial stress and circumferential stress show different characteristics in different parts of motor cores, which provides a theoretical basis for further analysis of vibration and noise reduction.