Time-varying magnetic-thermal-mechanical coupling model of giant magnetostrictive transducer under non-uniform magnetic field

Time-varying output characteristics of high-power giant magnetostrictive actuators (GMA) are determined by magnetic-thermal-mechanical coupling field effect. However, the influence of non-uniform magnetic field and temperature distribution on the output displacement of GMA is often ignored in the present researches. Therefore, a comprehensive model under multi-physics effects is established in this paper. Firstly, the leakage flux and eddy current effects are taken into account, and the non-uniform magnetic circuit model (MCM) is built. Then, the uneven power losses of heat source in GMA are analyzed according to the MCM results. A threedimensional time-domain thermal circuit is developed based on the heat transfer equation and the "T" equivalent thermal circuit model. Finally, the time-varying displacement is calculated on the basis of multi-degree-offreedom dynamics theory, so as to build the entire model. Compared with the traditional lumped parameter model and the steady-state thermal field researches, the proposed model is more accurate in analyzing temperature distribution and output characteristics of GMA under different working conditions. Furthermore, the proposed model can also provide a guidance for the temperature management methods and the optimal designing scheme of GMA in various application scenarios. The accuracy and effectiveness of the proposed model have been verified by experiments.