NiTi形状记忆合金棒的受限回复与加热试验及分析

发布时间：2018-03-24 10:23

  本文选题：形状记忆合金棒　切入点：受限回复　出处：《华南理工大学》2013年硕士论文

【摘要】：由于形状记忆合金的优良特性，其在土木工程领域的应用具有广阔前景。若将形状记忆合金棒制成螺栓用于地铁盾构管片，则当管片因外力出现某种程度张开时，利用形状记忆合金的受限回复性能可为管片提供一定的闭合回复力，进而为后续被动修复创造更有利的条件。为此，本文对NiTi形状记忆合金棒的受限回复性能和加热方法进行了初步研究，主要工作包括以下三部分： （1）通过形状记忆合金棒的拉伸与剪切受限回复试验，，考察了残余变形不同时受限回复力随温度的变化关系。研究表明：随着形状记忆合金棒的残余变形增大，无论是升温阶段还是降温阶段的最大受限回复力均随之增加；形状记忆合金棒以及约束装置的热胀冷缩将对试件的受限回复力产生较大影响。 （2）基于Brinson模型对形状记忆合金棒的拉伸受限回复过程进行了理论分析，指出了其存在的主要问题，并对此进行了改进；随后，基于改进的Brinson模型再次进行了理论分析，发现不同拉伸残余应变情况下形状记忆合金棒升温阶段的计算曲线以及降温阶段的前半部分计算曲线均与试验曲线吻合较好，特别是计算所得最大受限回复力与试验实测值较为接近。 （3）提出了一种新的形状记忆合金棒材加热方法，进行了相应的加热试验和计算分析，初步验证了其可行性。研究表明：采用提出的加热方法，SMA棒从常温升至110℃所需时间小于20min，升温效率较高，效果良好。
[Abstract]:Because of the excellent properties of shape memory alloy, its application in the field of civil engineering has a broad prospect. If the shape memory alloy bar is made into bolt to be used in metro shield segment, when the segment is opened to some extent due to external force, The limited recovery properties of shape memory alloys can provide a certain closed recovery force for the segments, and thus create more favorable conditions for passive restoration. In this paper, the limited recovery properties and heating methods of NiTi shape memory alloy rods are studied. The main work includes the following three parts:. 1) through tensile and shear confined recovery tests of shape memory alloy bars, the relationship between temperature and residual deformation is investigated. The results show that the residual deformation of shape memory alloy rods increases with the increase of residual deformation. The maximum limited recovery force increases in both the heating stage and the cooling stage, and the thermal expansion and contraction of the shape memory alloy bar and the restraint device will have a great impact on the limited recovery force of the specimen. (2) based on Brinson model, the tensile limited recovery process of shape memory alloy rod is theoretically analyzed, and the main problems are pointed out and improved. Then, based on the improved Brinson model, theoretical analysis is carried out again. It is found that the calculated curves of the heating stage and the first half of the cooling phase of the shape memory alloy bars under different tensile residual strains are in good agreement with the experimental curves. In particular, the calculated maximum limited recovery force is close to the measured value. A new heating method of shape memory alloy bar is proposed, and the corresponding heating test and calculation analysis are carried out. The feasibility of the method is preliminarily verified. The results show that the proposed heating method takes less than 20 minutes to rise from room temperature to 110 鈩

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