Micromechanics modeling and experimental characterization of shape memory alloy short wires reinforced composites

Shape memory alloys (SMAs) due to their extraordinary physical and mechanical properties، recently are used to enhance the mechanical properties of composites. In the present paper micromechanics model based on Eshelby’s equivalent inclusion and Halpin-Tsai model was used in order to predict the elastic properties of randomly oriented shape memory alloy short wires reinforced epoxy. The presented incremental micromechanics model considers the gradual changes in the elastic modulus of the SMA wires due to martensite phase transformation. Experimental tensile tests were applied to the shape memory alloy short wires/epoxy composites to investigate the accuracy of the model. The micromechanics results were in good agreement with the experimental results and also the previously reported results in the literature. The effect of shape memory alloy wires volume fraction as well as the aspect ratio of the wires was investigated on the elastic modulus of SMA/epoxy composites. Moreover the effect of orientation of SMA wires on the modulus of composites was studied. Micromechanics results showed that in SMA volume fractions lower than 5%، the minimum acceptable aspect ratio of wires is about 25، However for SMA volume fraction above 15%، aspects ratios above 40 are required in order to enhance the elastic modulus of the composites efficiently.