Variable coefficient magnetic energy loss calculating model for magnetostrictive materials considering compressive stress

The effect of variable compressive stress on hysteresis, eddy-current, and anomalous losses in magnetostrictive materials is investigated by the built magnetic characteristic testing system. Based on experimental results of Terfenol-D and loss separation theory, the trends of loss coefficients of three variables, magnetic frequency f, peak flux magnetic density Bm, and compressive stress σ, are analyzed. The reasons for the change in losses are explained from the point of view of micro-magnetism and physical mechanism. A variable coefficient magnetic energy loss calculating model considering compressive stress is derived using the algorithm of Levenberg–Marquardt and the method of multivariate parametric regression. The experimental and computed results of magnetic energy losses are compared and analyzed under different operating conditions. The analysis results show that the proposed model could well predict the losses under compressive stress at high-frequencies (5–20 kHz). The average error of the computed and experimental results is 5.5%. This research has improving significance in giving theoretical guidance for magneto-mechanical design in the high-frequency operated conditions of magnetostrictive devices.