【摘要】 研究了常温下循环加载次数、应变幅值、加载速率等对NiTi形状记忆合金丝相变应力、单圈耗能、变形模量、等效阻尼比及残余应变等力学性能参数的影响规律.结果表明:在一定加载速率下,随着循环次数的增加,正、逆向相变应力均有降低,正向相变应力降低的幅度更大,正向相变应力在20个循环后趋于稳定,逆向相变应力在5个循环后趋于稳定;单圈耗能随循环次数的增加而减小,从第1圈到第30圈,能耗减幅达33%;残余应变随循环次数的增加而增大,第30圈时达饱和值0.4%;等效阻尼比随应变幅值的增加呈先增大后减小的趋势,幅值7%时达最大值,卸载模量随应变幅值增大而减小;加载速率影响材料的相变应力及耗能,相变应力随加载速率增加而增加,材料的耗能能力随加载速率增加而降低,但降低幅度不大.更多还原

【Abstract】 This paper deals with the effects of the cyclic loading number,the strain amplitude and the loading rate on such mechanical behaviors of shape memory alloy wires as the phase transformation stress,the energy consumption per cycle,the deformation modulus,the equivalent damping ratio and the residual strain.Experimental results show that(1) at a certain loading rate,both the forward and the inverse transformation stresses decrease with the increase of the cyclic loading number,especially the former;(2) the forward transformation stresses tend to be stable after 20 cycles,while the inverse ones be stable after only 5 cycles;(3) with the increase of the cyclic loading number,the energy consumption per loading cycle decreases and the amplitude is up to 33% when the cyclic number increases from 1 to 30;(4) the residual strain increases with the increase in the cyclic loading number till to the saturation value of 0.4% after 30 cycles;(5) the equivalent damping ratio increases with the strain amplitude till to the maximum at a strain amplitude of 7%,then it slightly decreases,while the unloading modulus decreases with the increase in the strain amplitude;and(6) the loading rate affects not only the transformation stress but also the energy consumption-specifically,with the increase in loading rate,the transformation stress increases,while the energy consumption slightly decreases.更多还原