Temperature variation of a NiTi wire considering the effects of test machine grips
Temperature variation of a NiTi wire considering the effects of test machine grips
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DOI：
10.1007/s00707-015-1322-6
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发表时间：
2015-03
期刊：
影响因子：
2.7
通讯作者：
Shengyou Yang;Guansuo Dui;Baoyu Ma
中科院分区：
文献类型：
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作者：
Shengyou Yang;Guansuo Dui;Baoyu Ma
最近的实验表明，潜热释放/吸收所造成的试样温度变化的机械响应的NiTi SMA的传播应力和阻尼能力，由于相变应力对温度的依赖性，如放置一个重要的角色。本文研究了考虑试验机夹具影响的镍钛丝温度变化。除了与环境条件的热对流外，试样端部与试验机夹具之间存在的强烈热交换对温度演变有很大影响。为了研究这种影响的温度变化，提出了一个简化的模型，并得到了封闭形式的解决方案的轴向温度变化。通过两个典型案例验证了模型的有效性。当试样足够长时，它退化为Dirichlet边界条件.在试样较短的情况下，该模型得到的温度变化与以往工作中常用的Neumann边界条件下的温度变化相似。本文的结果具有明确的物理解释，可为实际中形状记忆合金器件的设计和仿真提供有益的指导。
Recent experiments showed that the specimen temperature variations caused by latent heat release/absorption place an important role on the mechanical responses of NiTi SMAs like the propagation stress and the damping capacity due to the dependence of phase transformation stress on temperature. This paper studies the temperature variation of a NiTi wire considering the effects of the test machine grips. In addition to the heat convection with the ambient condition, the existence of strong heat exchange between the specimen ends and the test machine grips highly affects the temperature evolution. To investigate this effect on temperature variation, a simplified model is proposed and the closed-form solution of the axial temperature variation is obtained. The validity of the model is verified by two common cases. In the case of sufficiently long specimen, it reduces to the Dirichlet boundary condition. In the case of relatively short specimen, the temperature variation obtained in this model is similar to that under the Neumann boundary condition usually used in the previous work. The results presented in this paper that have clear physical interpretations can give useful advice in the design and simulation of SMA devices in practice.