【作者】 郭斌；

【导师】 宋钢兵；

【作者基本信息】 大连理工大学 ， 结构工程， 2020， 硕士

【摘要】 基于压电陶瓷材料的局部结构健康监测技术(例如机电阻抗法和声发射技术等)已经成功的应用于土木工程领域,其中压电传感器是基于压电陶瓷材料的局部结构健康监测技术的核心设备。土木工程结构应用压电陶瓷传感器进行结构健康监测时,不同的场合对谐振频率要求不同。然而如何基于压电元件的不同谐振频率特征来设计传感器以满足不同场合的监测需求,目前还有很多问题有待进一步研究。针对此不足,本论文对压电元件的径向振动谐振频率特性进行深入研究,结合传统基于压电陶瓷材料的局部结构健康监测技术的特点,研发了适合于大型混凝土结构健康监测的压电传感器。以下为本文的主要研究内容:(1)深入研究了压电元件的谐振频率特性。本文从压电元件的谐振频率推导过程出发,建立了串联压电元件的等效电路模型。通过等效电路模型和有限元模拟,研究了串联前后压电元件的谐振频率特性。最后,通过实验进一步研究了压电元件串联前后的谐振频率特性。(2)基于串联压电元件谐振频率特性设计了串联压电元件阻抗传感器。结合串联压电元件的谐振频率特性和阻抗法的基本原理,提出基于串联压电元件阻抗传感器的多传感阻抗法。通过实验验证了多传感阻抗法监测灌浆密实度的可行性,并通过有限元模拟进一步研究了该方法的基本原理。(3)基于压电元件径向振动谐振频率特性设计了一款嵌入式声发射传感器。所设计的传感器可考虑混凝土材料裂纹发展释放的声发射信号的特征,适合于嵌入大体积混凝土结构中进行声发射监测,并通过混凝土单轴受压实验测试了设计的嵌入式声发射传感器的性能。更多还原

【Abstract】 Local structural health monitoring techniques based on piezoelectric ceramic materials(e.g.,Electromechanical impedance(EMI)method and acoustic emission technique,etc.)have been successfully applied in the field of civil engineering.When piezoelectric ceramic sensors are used for structural health monitoring in civil engineering structures,different occasions have different resonant frequency requirements.However,there are still many problems to be further studied on how to design sensors based on the characteristics of the resonance frequency of piezoelectric elements to meet the monitoring requirements.In order to solve this problem,the resonance frequency characteristics of the radial vibration of the piezoelectric element were studied in depth.Combining with the characteristics of the traditional local structural health monitoring technique based on piezoelectric ceramic materials,the piezoelectric transducers suitable for the health monitoring of large concrete structures are proposed.The following are the main contents of this paper:(1)The resonance frequency characteristics of the piezoelectric element are studied in depth.In this paper,an equivalent circuit model of a series piezoelectric element is established based on the resonant frequency derivation process of the piezoelectric element.The resonant frequency characteristics of piezoelectric elements before and after series are studied by equivalent circuit model and finite element simulation.Finally,the resonance frequency characteristics of the piezoelectric element before and after series are further studied by experiments.(2)Based on resonance frequency characteristics of series piezoelectric element,a series piezoelectric element impedance transducer was designed.Based on the resonance frequency characteristics of series piezoelectric element and the basic principle of impedance method,a multi-sensing EMI method based on series piezoelectric element is proposed.The feasibility of monitoring grouting compactness with multi-sensing EMI method is verified by experiments,and the basic principle of the method is further studied by finite element simulation.(3)An embedded acoustic emission sensor was designed based on the resonance frequency characteristics of the radial vibration of a piezoelectric element.Considering the characteristics of acoustic emission signals released by concrete cracks,the designed sensor is suitable for acoustic emission monitoring embedded in mass concrete structures.The performance of the designed embedded acoustic emission sensor is tested by concrete uniaxial compression experiment.更多还原