NiTi shape memory wires are fostered to be utilized as actuators due to their strain recovery capability involved with phase transformation and the high mechanical properties. Since large strains are involved with the phase transformation, fatigue is a crucial issue that needs to be carefully investigated. Fatigue of superelastic alloys is usually analyzed through S-N curves obtained by imposing alternated stresses. Differently, actuators based on shape memory alloys are usually subjected to a bias load and thermal cycles drive the actuation. This work presents an experimental characterization of the thermo-mechanical static and fatigue properties of shape memory NiTi wires intended for actuation purposes. A series of original results are presented. The wires’ stroke capability is found to depend on the heat rate and temperature associated with a varying magnitude of the current utilized to perform the thermal cycle exploiting the Joule’s effect. Alongside a reduction of the act...

中文翻译：

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电流对形状记忆镍钛丝热机械静疲劳性能的影响

由于NiTi形状记忆线的应变恢复能力与相变和高机械性能有关，因此被提倡用作致动器。由于相变涉及大应变，因此疲劳是一个至关重要的问题，需要仔细研究。通常通过施加交变应力获得的SN曲线来分析超弹性合金的疲劳。不同的是，基于形状记忆合金的执行器通常要承受偏压力，而热循环会驱动执行器。这项工作提出了形状记忆NiTi导线用于致动目的的热机械静态和疲劳特性的实验表征。提出了一系列原始结果。发现导线的行程能力取决于加热速率和温度，该速率和温度与利用焦耳效应进行热循环的电流大小变化有关。除了减少行为...