基于压电阻抗法的FRP加固混凝土结构健康监测方法研究

Fiber reinforced polymer (FRP) reinforcement technique has been widely used for the strengthening of reinforced concrete (RC) structures for its excellent material properties. However, this kind of strengthening often leads to structural failure due to concrete cracks and FRP debonding. Therefore, health monitoring of FRP-strengthened structure becomes a key problem to be solved. Herein, theoretical analysis, numerical simulation and experimental tests will be carried out in this study for the health monitoring of FRP-strengthened RC structure by using piezoelectric impedance method. First of all, theoretical piezoelectric impedance model of FRP-strengthened RC structure will be established, based on that, the principle of electromechanical coupling and the mode of energy transmission among structural components will be revealed. Then, the accuracy of theoretical model will be evaluated according to experimental tests, and influences of structural damage for piezoelectric impedance measurements will be analyzed. Finally, damage detection methodology will be proposed based on theoretical model and experimental tests by using impedance method. The investigation in this project are helpful for the theory of piezoelectric smart structures, furthermore, scientific basis can be provided for the health monitoring of FRP-strengthened structures.

纤维增强复合材料(FRP)以其优越的性能被广泛地应用于混凝土结构加固，但混凝土开裂、片材剥离等结构损伤常常导致加固失效，因此对FRP加固混凝土结构的健康监测成为亟待解决的关键问题。本课题拟通过理论分析、数值模拟和模型试验开展基于压电阻抗法的FRP加固混凝土结构健康监测研究。首先，项目将建立FRP加固混凝土结构的压电阻抗计算模型，揭示压电智能材料与FRP加固混凝土结构相互作用的力电耦合机理，阐明结构系统机械能和电能的转换模式。其次，通过模型试验，验证理论模型的计算结果，并分析结构损伤的累积和扩展对压电阻抗频谱的影响。最后，基于所得理论模型和试验数据，提出基于压电阻抗法的结构损伤识别及健康监测方法。研究成果将进一步丰富压电智能结构理论，同时也为FRP加固混凝土结构的健康监测研究奠定理论基础并提供科学依据。

纤维增强复合材料(FRP)以其优越的性能被广泛地应用于混凝土结构加固，但混凝土开裂、片材剥离等结构损伤常常导致加固失效。本项目利用压电传感器对FRP 加固混凝土结构开展了损伤识别研究。首先，利用压电传感器对金属梁、混凝土梁开展了损伤识别试验研究，分析了压电阻抗信号与结构损伤程度及损伤位置之间的关系，明确了压电阻抗法对结构损伤识别的有效性；开展了FRP加固混凝土梁加载试验，测试了各级损伤工况下的压电传感器阻抗信号；最后，基于简化的谱元法模型和损伤函数，对FRP加固混凝土梁开展了多层级损伤识别方法研究，实现了从结构整体到局部的损伤程度识别和定位。建立的基于压电阻抗法的多层级损伤识别方法，可推广应用于工程结构的损伤识别和健康监测。