【作者】 邱自学；

【导师】 张河；

【作者基本信息】 南京理工大学 ， 机械电子工程， 2002， 博士

【摘要】 结构健康监测是近年迅速发展的一项应用技术，涉及结构的连续监测、检查以及损伤探测。最终目的是增加结构的可靠性和安全性，降低结构维修的成本。可广泛应用于大型骨干设备的关键部件、桥梁、水坝、民用建筑、航空航天设备、化工容器、电力领域等实现运行状态监测。 本文正是针对上述工程需要，主要研究基于形状记忆合金(SMA)传感和驱动性能的结构健康监测技术，目的是探索SMA传感与驱动一体化，提供一种较简单、经济和可行的技术方法，用于对工程重要结构的在线监测。 全文的研究工作主要分为四个方面： 首先，在对SMA形状记忆效应和超弹性行为分析的基础上，系统研究和测试了SMA的传感和驱动性能。研究选择NiTi形状记忆合金丝材和Cu基记忆合金螺旋弹簧。对NiTi记忆丝及超弹性丝在恒温拉伸卸载、恒载变温以及形状回复过程中的应力-应变-电阻-温度之间的关系进行了系统的测试和分析；对Cu基螺旋弹簧在三种基本使用状态下的驱动特性进行了研究。实验结果表明，纯马氏体态、纯奥氏体态NiTi记忆丝及超弹丝具有应变传感性能，约束回复中的SMA与自然回复过程中的超弹丝具有力驱动性能，一定状态的SMA可实现自传感驱动；NiTi超弹性丝可用作结构健康监测的应变传感元件。 第二，研究基于超弹性形状记忆合金的复合材料结构冲击响应的监测。将一定规格的NiTi超弹性丝埋入复合材料结构，制作典型的实验构件。总结和分析了纤维增强复合材料冲击动力学行为及理论。通过低速冲击实验，研究利用SMA超弹性特性所具有的大应变及电特性实现结构健康监测的方法和可行性。研究表明，以一定方式埋入结构的超弹性传感元件可较好地实现对结构冲击位置和程度等响应的监测。 第三，研究埋入NiTi超弹性传感元件的复合材料结构强度的监测。设计和制作了用于拉伸、弯曲试验的实验构件。对含孔洞的典型构件进行拉伸试验，对方板构件进行弯曲模拟受载试验，实时采集结构中传感元件的输出，以实验的方法监测结构宏观力学行为。实验结果表明，埋入的超弹性传感元件可对结构的裂纹、断裂特性及强度等进行监测。 第四，研制完成用于材料冲击试验的多参数动态性能试验机和健康监测微弱信号调理与放大仪，完成了结构健康监测的实验系统。为了能实现对埋入NiTi传感元件的复合构件进行低速冲击试验，进行各参数的测试，研究自制了低速冲击试验机。该试验设备可实现对冲击力、冲击初始速度、冲击能量等参数的测量。研制完成用于超弹性传感元件监测的多路微弱信号调理与放大仪，构建了16路并行数据采集与分析摘要博士论文仪，从而完成了结构健康监测的实验系统，成功用于结构健康监测。更多还原

【Abstract】 Structural health monitoring (SHM) is an emerging applied technology in recent years, dealing with the development of techniques and system for the continuous monitoring, inspection and damage detection of structures, and its ultimate goal is to increase reliability, improve safety and reduce maintenance costs. The technology can be applied to monitor structures during their whole life, such as critical parts of high-rating key equipments, bridges, dams, buildings, aeronautic and astronautic instruments, chemistry industrial containers, and electrical powers.The research of this dissertation is intended to meet the above engineering’s needs, and develop a new kind of structural health monitoring technology based on sensing and actuating properties of shape memory alloys to provide a simple, economic and reliable technique method monitoring important engineering structures on line. Therefore, research on whether the shape memory alloy can be simultaneously used as sensor and actuator or not was conducted.Main research works can be summed up in four aspects.Firstly, the sensing and actuating characteristics of shape memory alloys were systematically studied and measured after analyzing shape memory effect and superelasticity. NiTi shape memory alloy wires and Cu-based helical springs were selected to test. The relationships among stress, strain, resistance and temperature of NiTi memory-wire and superelastic wire, which are in constant temperature, constant stress and shape recovery, were measured and analyzed. The actuating property of Cu-based spring in three basic conditions was investigated. Experimental results show that NiTi memory wire for pure martensite or pure austenite and superelastic wire has strain-sensing nature, and memory-wire and superelastic wire possess stress-actuating property during restrained recovery, and that NiTi superelastic wire can be used as strain-sensing element to monitor structural health condition.Secondly, structural impact response monitoring technology of composite materials based on NiTi superelastic nature was researched. Some typical experimental specimens embedded with superelastic wires were designed and fabricated. The dynamics of impact on fiber-reinforced composite structure was analyzed and summarized. Methods and reliability of structural health monitoring utilizing the large strain and electric property of shape memory alloy’s superelasticity were studied by low velocity impact test. Theconclusion is that NiTi superelastic-sensing elements embedded in structure can be well used to monitor impact responses, such as impact position, impact degree, and so on.Thirdly, structural strength monitoring of composite materials embedded with NiTi superelastic sensing elements was researched. Experimental specimens embedded with superelastic wires, which are rectangle laminated composite panels with a circular hole and square plate, were prepared to make respectively tensile and bending test. The outputs of sensors embedded in structures were timely acquired to monitor mechanical properties of structure. Research results show that NiTi superelastic wires embedded in structures can monitor fracture behavior and strength in the structures.Fourthly, a dynamic property tester used to impact structure, which has multi-parameters testing function, and a health monitoring signal conditioner and amplifier were developed, and experimental system applied to monitor structural health was established. In order to realize low velocity impact test and measure parameters for composite structures embedded with NiTi sensing elements, low velocity impact tester was designed and manufactured by ourselves, which can be used to measure impact force, impact velocity, impact energy and so on. The multichannel signal conditioners and amplifiers were developed to monitor superelastic wires embedded in structure, and 16 channels parallel data acquisition and processing system was set up. So, the experimental system was established and successfully used as structural health monit更多还原