Micromechanics of composites reinforced in the aligned SMA short fibers in uniform thermal fields

Analytical procedures are developed on the basis of the equivalent inclusion method and the Mori-Tanaka approach for a composite system consisting of shape memory alloy (SMA) short fibers within an elastic matrix subjected to uniform temperature. The incremental equivalent inclusion model is developed for studying the transformation behavior, transformation strain and thermal expansion coefficient of SMA composites under uniform thermal field conditions. Attention is focused on the discussion of the influence of the fiber volume fraction and fiber geometric ratio. The solution addresses the complexities induced by the nonlinear dependence of the in situ martensite fraction of the fibers on the local stress and temperature, and an iterative technique is necessary in the solution procedure. The results show that the transformation temperature band and transformation temperature points of the SMA composites are higher than that of the SMA materials, and the transformation strain coefficients and thermal expansion coefficients of SMA composites can be designed by changing thr fiber volume fraction and fiber geometric ratio.