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以NiTi合金在结构振动控制中的应用为背景,试验研究了加卸载循环次数和直径尺度对NiTi合金丝伪弹性特征的影响规律。研究结果表明,NiTi合金丝的残余应变随循环次数的增加呈指数关系增加,而其马氏体相变开始应力、奥氏体弹性模量、相变应变和等效阻尼比随循环次数的增加呈指数关系降低;随着直径尺度增加,循环加卸载后,NiTi合金丝的伪弹性退化程度显著增加。此外,残余应变与残余内应力、奥氏体弹性模量以及相变应变之间的线性关系揭示了NiTi合金伪弹性退化的内在机理。
Based on the application of NiTi alloy in structural vibration control, the effects of loading and unloading cycles and diameter on the pseudoelastic properties of NiTi alloys were studied. The results show that the residual strain of NiTi alloy wire increases exponentially with the increase of the number of cycles, and the martensite transformation start stress, austenite elastic modulus, phase transformation strain and equivalent damping ratio increase with the number of cycles The exponential relationship decreased. With the increase of diameter, the pseudo-elastic degradation of NiTi alloy wire increased significantly after cyclic loading and unloading. In addition, the linear relationship between residual strain and residual internal stress, austenite elastic modulus and phase transformation strain reveals the intrinsic mechanism of pseudoelastic degradation of NiTi alloy.