Multi-field Coupled Model And Application Research Of Magnetically Controlled Shape Memory Alloy

Magnetically controlled shape memory alloy（MSMA）,also known as ferromagnetic shape memory alloy,which not only have temperature controlled and magnetically controlled memory effects,but also have fast response,high energy density and other excellent features,have a broad application prospects as a potential intelligent actuator and sensor materials.However,the inherent hysteresis nonlinearity of MSMA affects the positioning accuracy of MSMA actuator,which limits the application of the alloy in the field of precision positioning.In this paper,N i₂MnGa magnetically controlled shape memory alloy was used as the research object.The multi-field coupled model was constructed by using the law of energy conservation under the stress-magneto-thermal coupled condition,and the hysteresis nonlinearity of MSMA was studied deeply.The main research contents are as follows:（1）With stress-magneto-thermal multi-field coupled loading measurement system of MSMA,experiments were carried out by controlling the experimental temperature and magnetic field strength.Then,the experimental data such as external stress,temperature,magnetic field and MSMA strain were recorded.Based on the experimental data,the MSMA multi-field coupled model was constructed by using the law of conservation of energy and thermodynamics theory.The model predicted the multi-field coupled variable curve by the parameter identification method.More importantly,the best operational coupling condition of MSMA actuator was obtained which is helpful to realize the high precision positioning of the MSMA actuator.（2）Against the positioning accuracy problem of MSMA actuator,the reasons of hysteresis nonlinear phenomenon was analyzed by microcosmic theory of magnetic domain wall motion.Based on those reasons,a method to improve the positioning accuracy of actuator was proposed by reducing the error of MSMA hysteresis.In this paper,MSMA hysteresis nonlinear was reduced by improving the accuracy of fitting,increasing the hysteresis compensation ability,optimizing the control method and controlling the working temperature.Ultimately,the precise positioning of MSMA actuator was achieved...