Modeling 2-D Magnetostriction in Nonoriented Electrical Steels Using a Simple Magnetic Domain Model

Magnetostriction in electrical steel is a source of acoustic noise and vibration of rotating electrical machine cores. Magnetostriction of nonoriented (NO) steel under 2-D magnetization is much greater than that under unidirectional, alternating magnetization. An analytical interpretation of the relevance of 2-D magnetostriction and magnetostrictive anisotropy of NO steel based on a simple magnetic domain model is presented. The analysis helps explain the effect of anisotropy on 2-D magnetostriction measurements made on commercial NO steels with different anisotropy factors. The magnitude of the 2-D magnetostriction is shown to depend on the magnetostrictive anisotropy and magnetic Poisson´s ratio.