动载荷下梁结构非线性损伤的光纤光栅实时监测和识别方法

项目名称： 动载荷下梁结构非线性损伤的光纤光栅实时监测和识别方法

项目编号： No.51308428

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 建筑科学

项目作者： 罗裴

作者单位： 武汉理工大学

项目金额： 25万元

中文摘要： 工程结构早期非线性损伤诊断是目前结构损伤识别领域的挑战性难题。针对现有电类传感技术难以实现远距离、分布式、实时监测和提取动载荷下大型复杂结构早期非线性损伤特征信号问题，本项目提出搭建金属梁结构健康状态的光纤光栅实时监测实验系统，采用激光预制早期微小裂纹，通过光纤光栅应变传感阵列和光纤光栅振动传感阵列并用，研究恒定载荷下早期裂纹特征(裂纹大小、数量、形状)对金属梁结构应力应变和本征模态参数的影响规律；在此基础上，重点研究动载荷下早期裂纹扩展过程中金属梁结构应力应变和本征模态参数的变化以及裂纹扩展引起的金属梁结构非线性损伤演变规律；采用小波变换时频分析方法提取早期裂纹扩展产生的非线性损伤特征信号，构建结构损伤BP神经网络智能识别模型。建立动载荷下梁结构非线性损伤的光纤光栅实时监测和识别新方法，推动光纤光栅远距离、分布式、多参数传感技术在大型复杂结构早期非线性损伤的实时监测与识别中的应用。

中文关键词： 梁结构；动载荷；非线性损伤；光纤光栅传感阵列；实时监测

英文摘要： The early nonlinear damage diagnosis of engineering structures is now a challenging problem in the field of structural damage identification. The research program of this project is suggested based on the practical problem that the existing electrical sensing technology very difficultly realize to real-timely monitor and extract the characteristic signal of the early nonlinear damage of large and complex structures on the long distance and distributed scale. An experimental system has been constructed according to the finite element analysis results in order to real-timely monitor the health status of metal beam structures using FBG strain sensor array and a fiber grating vibration sensor array. The research works of this project are included: (1) to prefabricate the early small cracks using the laser etching method; (2) to investigate the influences of the early crack characteristics (shape, size, and quantity) on the stress strain and intrinsic mode parameters of metal beam structures under condition of a constant load and a fixed vibration frequency; (3) to investigate the fiber grating real-time monitoring method of the stress strain and intrinsic mode parameters of metal beam structures under dynamically loading and random vibration frequency; (4) to reveal the nonlinear variation laws of the nonlinear dama

英文关键词： Beam structure；Dynamically loading；Nonlinear damage；fiber grating sesing arrays；real-time monitoring