Mechanical Properties And Constitutive Model Of Ferromagnetic Shape-Memory Alloy Epoxy Composites

Ferromagnetic shape memory alloy is a new type of shape memory alloy which was developed in the 1990 s.It not only has the physical effects of magnetothermal and magnetoresistive,but also has the characteristics of temperature control,stress control and magnetic control.At present,ferromagnetic shape memory alloys are brittle,which is difficult to be processed,and can not be used in engineering.In this study,ferromagnetic shape memory alloy was combined with epoxy resin to obtain a new type of composite material-ferromagnetic shape memory alloy/epoxy resin composite.The composite not only maintains the mechanical properties of ferromagnetic shape memory alloy,but also effectively corrects the shortcomings of ferromagnetic shape memory alloy,which provides a new idea for further promoting the application of this smart material in engineering practice.Firstly,this paper prepared ferromagnetic shape memory alloy/epoxy resin composite material specimens with different volume fractions and particle diameters.All of them were subjected to mechanical training.After mechanical training,their stress resistance was improved by about 0.4%.Then,the material specimens were tested for mechanical properties.Based on the test data,the purpose was to explore the influence of volume fraction and particle diameter on the mechanical properties of ferromagnetic shape memory alloy/epoxy resin composite.Secondly,based on thermodynamic theory,combined with Eshelby equivalent inclusion principle and Mori-Tanaka field average method,martensitic 1(magnetic field preferred martensitic variant)in ferromagnetic shape memory alloy is regarded as inclusion phase and martensitic 2(stress preferred martensitic variant),and the constitutive model of ferromagnetic shape memory alloy is established.Lastly,by applying Eshelby’s equivalent inclusion principle and Mori-Tanaka field average method,the particles of ferromagnetic shape memory alloy as a whole are regarded as inclusion phase and epoxy resin as matrix phase,and the meso-thermodynamic constitutive model of preferred martensitic reorientation of ferromagnetic shape memory alloy/epoxy resin composite is derived.Finally,by using the ABAQUS platform,ferromagnetic shape memory alloy/epoxy resin composite was used for finite element simulation analysis.In order to more truly reflect the mechanical properties of the overall composite material,a script of particle random distribution was written to simulate the randomness of the shape of ferromagnetic shape memory alloy and its random distribution in the inner space of the matrix by taking advantage of the characteristics of the meso-structure of ferromagnetic shape memory alloy.The written random distribution script was imported into ABAQUS for statics simulation analysis,and the final stress-strain curve was roughly similar to the results of the derived constitutive model,which verified the accuracy of the ferromagnetic shape memory alloy/epoxy resin composite constitutive model.This paper not only reveals the special mechanical properties of ferromagnetic shape memory alloy/epoxy resin composites,but also provides theoretical basis for many special applications of ferromagnetic shape memory alloy materials in practical life.