Homogenized Magnetoelastic Behavior Model for the Computation of Strain Due to Magnetostriction in Transformers

This paper deals with the prediction of the deformation of a multilayer transformer core made of an assembly of anisotropic E-shaped and I-shaped sheets. This magnetomechanical coupled problem is solved by a stepping finite-element method sequential approach: magnetic resolution is followed by mechanical resolution. A 3-D simplified multiscale model describing both magnetic and magnetostrictive anisotropies is used as the constitutive law of the material. The transformer core structure is modeled in 2-D, and a homogenization technique is implemented to take the anisotropic behavior of each layer into consideration and define an average behavior at each element of the finite-element mesh. A three-layer transformer prototype is fabricated with Hi-B grain-oriented iron-silicon alloy. Experimental measurements are carried out and compared with the modeling results. Small discrepancies are observed and discussed.