【摘要】 试验研究了4种直径形状记忆合金棒材的力学性能,分析了热处理工艺、循环加卸载次数、应变幅值对棒材力学特性的影响,探讨了残余应变、单循环耗能、割线刚度和等效阻尼比等力学特征参数随循环次数和应变幅值的变化规律。研究结果表明,对于直径14 mm棒材,选择400℃保温15 min的热处理方案时相变应力最高;循环5次后,材料的各项力学性能基本稳定,在工程应用时应该予以考虑。试验的结果为大直径SMA棒材应用于自复位结构提供了依据。更多还原

【Abstract】 Cyclic tensile tests of shape memory alloy bars with four different diameters were conducted. The effects of heat treatment, cyclic loading-unloading numbers, strain amplitude on the mechanicalbehaviour of SMA bars were analyzed. The mechanical parameters such as residual strain, energy dissipation per cycle, secant stiffness, equivalent damping ratio were studied with different strain amplitude and cyclic loading-unloading numbers. The experimental results indicate that the phase transformation stress was higher when the heat treatment scheme was 400 ℃ for 15 min for 14 mm SMA bar. The mechanical properties were basically stable after 5 cyclic loading-unloading cycles, which should be considered in engineering applications. The test results provided a basis for the use of large size SMA bars in self-centering structures.更多还原