Research On The Magneto-Mechanical Coupling Properties Of Ferromagnetic Shape Memory Alloy Composites

Ferromagnetic Shape Memory Alloy(FSMA)is a new type of smart material with special magnetic-controlled shape memory properties.Under the action of external magnetic field,large macroscopic strain can be obtained.Compared with shape memory alloy,FSMA has dual functions of sensing and driving,and has wider practical applications than shape memory alloy.However,in the process of research,it is found that FSMA is fragile,difficult to process and high cost,which is not conducive to its application in practical engineering.In order to maintain the original performance of FSMA and improve its own defects,this paper made FSMA composite material by combining FSMA particles with epoxy resin,and carried out experimental and theoretical research on its magneto-mechanical coupling characteristics.The mechanical properties of FSMA composite are jointly determined by the properties of epoxy resin and FSMA particles.In this paper,a three-phase theoretical model of matrix,magnetic field preferred variant and stress preferred variant is established by using the method of micromechanics.Based on Eshelby’s equivalent inclusion principle and Mori-Tanaka mean field method,the constitutive model of FSMA and FSMA composites is structured.The stress-strain properties of FSMA and FSMA composites under the action of applied stress and magnetic field are studied respectively.Combined with the phase transition of FSMA,the relation function between the critical stress of martensite body orientation and magnetic field and the volume fraction equation of martensite are proposed.The results show that the magnetic field strength is the key factor affecting the reorientation strain of FSMA composites.FSMA composites can produce about 5.0% reorientation strain,compared with the maximum reorientation strain of FSMA material,it is not greatly limited,and the maximum stress is about 80 MPa.FSMA composite can better withstand pressure and is not easy to cause material damageIn the part of finite element analysis,the mechanical behavior of isotropic and anisotropic composites under the action of stress and the influence of inclusion radius on the elastic modulus of the whole composite were compared,and the finite element results were compared with the experimental curve.The trend of simulation results was consistent with the experimental results,indicating that the finite element model can effectively simulate the mechanical behavior of FSMA composites.