由高频振动响应识别结构早期损伤的多分辨分形理论与方法

项目名称： 由高频振动响应识别结构早期损伤的多分辨分形理论与方法

项目编号： No.51508156

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： 白润波

作者单位： 河海大学

项目金额： 20万元

中文摘要： 基于结构振动响应的无损检测是目前国际结构健康监测领域的一个研究热点。然而其存在抗噪能力弱、对轻微损伤不敏感、基于高频振型的损伤检测效果不佳等不足。该项目以克服这些不足、构建基于高频振型的结构早期损伤检测新理论、新方法为目标,拟建立求解含损伤结构高频振动模态的谱元法解析模型；提出将结构高频振型转换为拟基频振型的方法，以消除高频振型在损伤检测应用上的固有缺陷，并充分发挥高频振型对局部损伤更敏感的优点；将多尺度思想引入模态分析领域，构建多尺度振型空间，使原始振型中的趋势、噪声、损伤信息成分得以独立表征；提出多分辨分形维物理量，建立结构损伤识别的多分辨分形维谱动力表征机制，使之具备抗噪能力强和对轻微损伤敏感的双重优点；开展基础模型试验以检验所提理论和方法，并为结构高频振动响应测量积累试验经验。预期成果可望有效解决现有方法的弊端，有力提升基于振动理论的结构损伤检测水平。

中文关键词： 结构监测；损伤识别；高频振型；分形；谱元法

英文摘要： Vibration response based nondestructive testing is a research hotspot in the structure health monitoring field. However, the existing methods are commonly suffered from several limitations as low immunity to noises, insensitivity to the weak damage, and poor damage detection results using high-frquency mode. The project aims to develop a new method for detecting incipient damage based on high-frequency vibration modes to overcome the limitations aforementioned above. The study consists of four closely-related sub-tasks: i) establish the damage structure models for high-frequency vibration modes based on spectral element method; ii) put forward a method for converting the high-frequency modes to the quasi fundamental ones, in order to overcome the inherent defects of high-frequency modes in damage detection and give full play to the advantages of high-frequency modes contains the damage information more abundant; iii) introduce the multi-scale idea into the field of construction of modal analysis and put forward a physical quantity named multiresolution fractal dimension. Using the multiresolution fractal dimension spectrum characterization of dynamic mechanism a structural damage identification method is established with a strong anti noise ability and sensitive to minor damage; and iv) carry out model tests to verify the proposed theory and methods, and accumulate experience for high-frequency modal measurement test. The fruits are expected to effectively solve the drawbacks of existing methods and enhance the level of structural damage detection based on vibration theory.

英文关键词： structure monitoring;damage identification;high-frequency vibration mode;fractal;spectral element method