Shape Memory Alloy Superelastic And Applied Research

In the paper, the superelasticity of shape memory alloy (SMA) are simulated. Themain work is divided into the following six aspects:Part 1 The properties and the researchful state of SMA are briefly reviewed. Thecontent of this paper is mentioned.Part 11 Auricchio superelastic model is introduced.Part III Anisotropic effects of polycrystalline shape memory alloys on the phasetransformation are analyzed. For different orientations the grains have differentmaterial properties which are assumed as uniform distributions. And experimentalresults indicate that although the result based on the hypothesis is a little larger thanthe experimental data, it provides a simple and appropriate method.Part IV Two kinds of SMA composites are researched. The strength of the compositesis increased by SMA reinforced fiber. The mechanical behavior of the compositesdepends on the SMA volume fraction. For normal metal-fiber reinforced SMA matrixcomposites, the SMA phase transformation is affected by the increasing Young'smodulus of the metal fiber.Part V SMA composites for cracked board repair are studied. The repair efficiencycan be enhanced by active closure stress which is produced by shape recovery ofpre-stretched SMA wires. With the increasing of the pre-strain, volume fraction andpatch thickness, the stress intensity factor decreases.Pan VI The mechanical responses of SMA have been investigated. Calorimetryreveals the presence of three phase transformations. In the uniaxial tensile test, thestress softening effect of martensite band leads to a macroscopic stress drop for wholematerial. Under cyclic loading, the initial and final stress of the phase transformationdecrease and the residual strain increases.