Homogenized magneto-elastic behavior model for the computation of strain due to magnetostriction in transformers

Abstract : This paper deals with the prediction of the deformation of a multi-layer transformer core made of an assembly of anisotropic ’E-shaped’ and ’I-shaped’ sheets. This magneto-mechanical coupled problem is solved by a stepping finite element method sequential approach: magnetic resolution is followed by mechanical resolution. A 3D Simplified Multi-Scale Model (SMSM) describing both magnetic and magnetostrictive anisotropies is used as the constitutive law of the material. The transformer core structure is modeled in 2D and an 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 grainoriented iron-silicon alloy. Experimental measurements are carried out and compared to the modeling results. Small discrepancies are observed and discussed.