Anisotropic magnetostriction of non-oriented silicon steel sheet and its frequency dependence

Non-oriented (NO) silicon steel sheet is widely used as industrial materials in electrical machine, and its magnetostriction is a key factor of causing vibration and noise of a large-scale synchronous machine. There have been some foregoing researches to develop magnetostriction of silicon steel sheet under alternating and rotational magnetic flux density based on a two-dimensional (2-D) magnetic measurement system, in which the sample was 60mm square, and the three-axis strain gauge was employed to measure the in-plane magnetostriction at arbitrary direction. In this paper, an improved one-dimensional (1-D) magnetostriction tester was built to measure the principal strain along different magnetization directions, and the anisotropic magnetostriction was discussed. The model describing the vector relation between the principal strain and magnetic flux density (B) was established and applied to the finite element (FE) analysis of magnetostriction in stator core of a synchronous machine. The validation of proposed method is verified.