摘 要

在结构监测领域，裂纹的监测始终是很重要的一部分。焊缝连接作为金属结构主要的一种连接方式，与金属结构的工作性能、使用寿命息息相关，而在长期的工作受载情况下，焊缝处容易产生裂纹，裂纹的扩展易使结构断裂。目前，国内外关于裂纹监测的传统方法研究已经较为成熟，但在运用贴片天线传感器进行焊缝裂纹监测的研究还较为缺乏。

本文围绕金属结构焊缝上裂纹扩展的监测问题进行讨论，研究了一种基于贴片天线传感器的焊缝裂纹扩展监测技术，设计出了用于焊缝裂纹大范围监测的贴片天线传感器阵列，并运用理论计算和有限元仿真进行了裂纹监测性能方面的深入研究。主要内容如下：

（1）根据“传输线模型”理论进行了贴片天线传感器设计方法的分析，并通过阻抗匹配的方式对馈线结构进行了设计。进一步运用“空腔模型”理论对贴片天线传感器的内场进行了求解，并对贴片和接地板平面的电流分布进行了分析，得出了电流密度的解析式，从而得出了基于电长度的裂纹识别原理。在此基础上进行了贴片天线传感器阵列的理论分析，主要通过阻抗法和散射法研究了传感器阵列阵元间的“互耦效应”，最后分析了贴片天线传感器阵列的裂纹监测原理。

（2）对基于平面焊缝形状的贴片天线传感器参数进行了设计，以阻抗匹配的方式进行优化设计，考虑了焊缝参数对于贴片天线传感器的影响，并利用Ansoft HFSS软件进行仿真分析，找出了焊缝粗糙度、焊缝余高和焊缝宽度三大参数对传感器工作谐振频率的影响。最后对平面焊缝上的简单直裂纹扩展进行了模拟仿真分析，探究了在裂纹扩展过程中贴片天线传感器的谐振频率变化情况

（3）基于柱状焊缝结构进行了贴片天线传感器参数的设计，建立仿真模型，探究了柱状结构半径对于贴片天线传感器工作谐振频率的影响。最后对柱状焊缝上的裂纹扩展进行了仿真研究，并将柱状焊缝中贴片天线传感器的谐振频率偏移情况与平面焊缝中的谐振频率偏移情况进行了比较，分析了在不同结构形状下的贴片天线传感器监测灵敏度。

（4）在上述单个贴片天线传感器的焊缝裂纹监测研究的基础上，对基于焊缝形状的贴片天线传感器阵列进行了参数设计，主要从阵元的“有效监测范围”和阵元间的耦合作用入手，对传感器阵列的阵元尺寸、阵元间距、馈线结构进行了设计。最后就贴片天线传感器阵列对焊缝裂纹扩展的监测效果进行了仿真分析，得出了用于焊缝裂纹监测的定性识别方法。

本文的研究工作对贴片天线传感器及其阵列对于焊缝裂纹监测的可行性进行了验证，对实际工程上的贴片天线传感器应用具备参考价值。

关键词：贴片天线传感器；传感器阵列；谐振频率；结构健康监测；焊缝裂纹识别

Abstract

In the field of structural monitoring, crack monitoring is always an important part. As one of the main connection modes of metal structure, weld connection is closely related with the working performance and service life of metal structure, and in the long-term operation of the load, cracks are easily formed at the weld, and the crack expansion will make the structure break easily. At present, the research on the traditional method of crack monitoring at home and abroad has been more mature, but the research on weld crack monitoring by using patch antenna sensor is still lacking.

In this paper, the monitoring problem of crack propagation on metal structure weld is discussed, a weld crack propagation monitoring technology based on patch antenna sensor is studied, a patch antenna sensor array for large range monitoring of weld crack is designed, and the crack monitoring performance is studied by theoretical calculation and finite element simulation. The main contents are as follows:

(1) According to the theory of "transmission line Model", the design method of patch antenna sensor is analyzed, and the feeder structure is designed by impedance matching. Furthermore, the inner area of the patch antenna sensor is solved by using the theory of "cavity model", and the current distribution of the patch and the floor plane are analyzed. The analytical formula of the current density is obtained, which leads to the crack recognition principle based on the electric length. On this basis, the theoretical analysis of patch antenna sensor array is carried out, and the "mutual coupling effect" between sensor array elements is studied mainly by impedance method and scattering method. Finally, the crack monitoring principle of patch antenna sensor array is analyzed.

(2) The sensor parameters of patch antenna based on planar weld shape are designed, the optimization design is carried out in the way of impedance matching, the influence of weld parameters on the patch antenna sensor is considered, and the simulation analysis is carried out by using Ansoft HFSS software to find out the influences of three parameters of weld roughness, weld height and weld width on the resonant frequency of sensor. Finally, the simulation analysis of the simple straight crack propagation on the planar weld is carried out, and the variation of the resonant frequency of the patch antenna sensor in the process of crack propagation is investigated.

(3) Based on the cylindrical weld structure, the sensor parameters of the patch antenna are designed, and the simulation model is established. The influence of cylindrical structure radius on the working resonant frequency of patch antenna sensor is investigated. Finally, the crack propagation on the cylindrical weld is simulated, and the resonant frequency offset of the patch antenna sensor in the cylindrical weld is compared with the resonant frequency offset in the planar weld, and the monitoring sensitivity of the patch antenna sensor under different structural shapes is analyzed.

(4) On the basis of the research on weld crack monitoring of the single patch antenna sensor, the parameter design of the patch antenna sensor array based on weld shape is carried out, and the array size, array spacing and feeder structure of the sensor array are designed mainly from the "effective monitoring range" of the array elements and the coupling between the elements. Finally, the monitoring effect of patch antenna sensor array on weld crack propagation is simulated and analyzed, and a qualitative identification method for weld crack monitoring is obtained.

The research work of this paper verifies the feasibility of the patch antenna sensor and its array for weld crack monitoring, and has certain reference value for the application of patch antenna sensor in practical engineering.

Keywords: microstrip antenna sensor，sensor array，resonant frequency，structural health monitoring，weld crack identification

目 录

摘 要 I

Abstract II

第1章 绪 论 1

1.1 研究工作的背景及意义 1

1.2 国内外研究现状 1

1.2.1. 关于贴片天线传感器的研究 1

1.2.2. 关于裂纹监测的研究 3

1.2.3. 关于贴片天线传感器阵列的研究 4

1.3 研究内容与创新 4

1.3.1. 基于焊缝形状的贴片天线传感器设计 4

1.3.2. 贴片天线传感器阵列设计及耦合影响因素分析 4

1.3.3. 柱状结构焊缝裂纹监测的影响因素分析 4

1.3.4. 本文主要的创新点 5

1.4 本文的结构安排 5

第2章 贴片天线传感器的理论基础 7

2.1 贴片天线传感器的理论基础 7

2.2 “传输线模型”理论与贴片天线设计 7