项目名称： 悬索桥吊杆损伤的两阶段精细化诊断与性能综合评估方法

项目编号： No.51508070

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 建筑科学

项目作者： 安永辉

作者单位： 大连理工大学

项目金额： 20万元

中文摘要： 本项目从构件层次研究吊杆的两阶段精细化诊断与性能评估：基于振动信息的损伤诊断和基于损伤回波的局部缺陷定位和定量。前者可快速初判损伤吊杆但难以评估局部缺陷；后者可评估局部缺陷但吊杆根数多致效率低。本项目联合这两种方法使其扬长避短，主要内容有：(1)在时域里构造反映吊杆损伤前后振动响应改变的损伤特征函数进而构建损伤诊断指标；提出方法对损伤和吊杆长度的敏感性研究；抗噪声水平研究；受温度的影响及有效的消除措施研究；(2)吊杆精细化建模；发展激励和接收线圈的优化布置方法；吊杆导波多模态以及频散特性分析；应力、环境、钢丝间接触效应耦合下导波传播特性研究；分析高背景噪声下损伤回波进而对局部缺陷定位和定量；(3)基于损伤吊杆整体信息和局部缺陷信息的性能评估；(4)基于悬索桥模型的试验验证。本法不需悬索桥数值模型、方便快速、成本低廉，为吊杆检测和评估提供了新思路及理论与试验支撑。

中文关键词： 两阶段精细化诊断；损伤特征函数；损伤回波；性能评估；吊杆

英文摘要： This project studies a two-stage approach of precise damage diagnosis and performance assessment for suspension bridge suspender cables from the level of structural components: i.e. the vibration-based damage diagnosis method and the defect reflective echo wave-based damage localization and quantification method of the local damage. Damaged suspender cables can be diagnosed but further performance assessment cannot be conducted based on the first method; the second technique can be used to accurately assess the local damage on the suspender cable, but it is costly and not efficient to be used in large number of suspender cables one by one. This project combines the two techniques and the combination makes best use of their advantages and bypass the disadvantages, and the main contents are listed as follows: (1) to develop a damage feature in time-domain that can indicate changes in responses of suspender cables before and after damage and then extract a damage index; to investigate the sensitivity of the proposed method on damage and the length of suspender cables; to investigate the anti-noise ability; to investigate the influence of temprature change and the effective measure of eliminating the influence; (2) finite element modeling of the suspender cable; to study the optimal sensor placement method of excitation and receiving sensors; to analyse the multiple modes and dispersion characters of the guided wave; to investigate the propagation property under the interreaction of stress, environment and contact effect; to localize and quantify the local damage through analysis of defect reflective echo waves with high level of noise; (3) to assess the performance of the damaged suspender cable based on overall information of the cable and local information of the defect; (4) to validate the proposed method based on experiments of a suspension bridge model. The proposed method in the present project doesn't require a finite element model of the suspension bridge, and it works easily and fast with low cost, which provides a new idea with theoretical and experimental support for accurate damage detection and safety assessment of the suspender cables.

英文关键词： two-stage precise damage diagnosis;damage feature;defect reflective echo wave;performance assessment;suspender cables