Effect of magnetostriction on the elastic properties of goss-oriented Si-Fe sheet subject to bending

Samples of Epstein size (305 mm × 30mm × 0.3 mm) of Goss-oriented silicon-iron sheet have been subjected to static bending sufficient to cause longitudinal curvature of up to 4 m^-1. The relationship between bending moment and curvature, expressed in terms of a so-called bending modulus with the dimensions of Young´s modulus, is shown to be nonlinear. The nonlinearity is due to a combination of a) the interaction between magnetostrictive and elastic effects in the material (ΔE effect), and b) the effect of anticlastic curvature, which depends on the dimensions of the sheet. Both effects are examined theoretically. Changes of bending modulus of up to about ±16% were measured on the small samples, in agreement with theory; and changes of up to + 29% are tentatively predicted for large sheets.