Abstract: The functionally graded shape memory alloy(FG-SMA) is a new functional composite which possesses the excellent properties of both functionally graded material(FGM) and shape memory alloys(SMA). A macroscopic constitutive model of FG-SMA is established by using the mechanics of composite materials method and the existing SMA model. With this macro constitutive model, the mechanical behavior of a FG-SMA beam composed by elastic material A and SMA subjected to pure bending is investigated. The loading processes including elastic process and phase transformation process are discussed in detail and the analytical solutions are obtained. The distribution of stress on the cross section, the position of the neutral axis and the curvature-bending moment relation are discussed through numerical results. It can be learned that compared with common FGM, FG-SMA can decrease the maximum stress efficiently, preventing the destruction caused by oversize stress. This research can provide a base for the design and in-depth investigation of FG-SMA material.

Key words: Functionally graded material, Pure bending, Shape memory alloy