梁类结构基于损伤特征指标的不确定性损伤识别方法研究

Civil structures begin to deteriorate once they are bulit due to harsh envirionment such as corrosion,earthquake,and typhoon.Structural damage detection methods have thus attracted considerable attention for assessment of functionality and safety of civil structures.Nevertheless,the damage detection of civil structures still remains as a challenging task.One of the main obstacles is that the current damage detection methods are either insensitive to local structural damage or sensitive to measurement noise.In addition,a significant amount of uncertainties are inherently and inescapably associated with the structural damage detection of civil structures,which limits the successful application of most deterministic damage detection method.At the same time,a majority of frame structures, bridges, high-rise buildings, special-shape and long-span spatial structures belong to the beam-type structures if considering the mechanical mechanism in the form of structural member or the whole. In this regard, based on the exsited problens of structural damage identification related to bending-type structures,four parts will be studied if this project is set up: Part I: Research on the damage feature indices and corresponding probabilistic characteristics. This section will be focused on the establishment of standard criterion for selection of damage feature indices which are sensitive to damage localization. Part II: Focusing on quantities and tranform of parameter uncertainties which may result from environment,such as temperature,loading and humidity,measurement noise,uncertainty in geometry and boundary conditions,inexact modeling of the material constitutive behavior or damaging,uncertainty in external excitations, and so on. In view of probability analysis,the anti-noise evaluation and random parameters sensitivity of damage feature indices are the main points in this section.The main objective of this section is to explore a more significant way in evaluation the identification capability of different damage feature indices and the influence of various uncertain parameters with noise on identification results. Part III: In consideration of uncertainties, reliability evaluation method of structural multi-scale damage diagnosis and prognostic will be studied carefully. In this regard, assessment system of structural damage identification under uncertainties will be significatively improved. Part IV: The thresholds of safety and damage level for structural performance state indicator,which combine different damage feature indices, will be focued on this section. In the end, a framework of platform in which stochastic approaches in consideration of the uncertainties involved in measurements,structures and external excitations are proposed to detect damage of beam-type structures and assess their reliability effectively.

结构损伤识别是结构检测和健康监测中具有挑战性的课题之一。由于环境噪音及不确定性因素的存在，到目前为止还没有简单实用和公认的损伤识别方法可供结构工程师应用。同时从力学机制上，梁类结构涉及到普通框架、高层、大跨、高耸及异性、桥梁等诸多结构类型，因此，本项目以目前梁类结构损伤识别中存在的问题为背景，展开如下四方面研究：（1）研究能够反映工程结构损伤局部化特点及敏感的损伤特征指标及其概率统计特征。（2）损伤识别过程中的环境、荷载和结构特征参数不确定性的量化和传递分析。（3）结构多尺度损伤诊断及预后的不确定性分析及可靠性评估。（4）基于结构检测和健康监测系统的结构状态性能指标安全阈值和损伤门槛值研究，进行相应软件平台开发。为科学评估结构损伤状态、完善健康监测系统的工程应用提供切实可行的帮助。

通过本项目三年的实施，课题组开展了如下研究内容：（1）研究通过单一模态识别结构单元刚度的SVI指标及基于输出统计矩指标的结构损伤局部化特点及其概率统计特征。（2）研究了考虑基于不确定因素下的单参数和双参数随机性的概率密度演化结构损伤识别原理及方法。（3）研究了不同噪音程度、不同测试点分布、不同损伤位置及不同损伤程度下的框架及桥梁结构损伤识别数值及试验分析研究。（4）研发了基于OpenSees Navigator的系统识别工具箱初步，可进行平面和三维结构下的损伤评估初步分析。（5）对桥梁检测，利用测试车动力信号进行结构损伤识别的初步研究。. 在项目实施资助下，主要成果如下：作为主研人（4/26）参编了国家建筑与桥梁结构国内外唯一一本国家标准《建筑与桥梁结构监测技术规范GB50982-2014》，并主编了该规范唯一一本实施指南《建筑与桥梁结构监测技术规范应用与分析GB50982-2014》。已发表SCI论文3篇（3区1篇，4区2篇），发表EI论文2篇，已录用（待发表）EI论文1篇，已申请发明专利1项。培养研究生7名（1名博士、4名硕士、2名在读），并邀请加州大学伯克利分校土木与环境工程系，太平洋地震工程研究中心主任Khalid M.Mosalam访学一次。. 通过本项目系统研究，揭示了动力响应参数，特别是模态参数与结构损伤之间的关系，系统性的分析了本项目所研究方法的适用范围及应用前景。考虑实际情况，将损伤识别的不确定性分析方法与结构检测和健康监测，以及有限元模拟的不确定性紧密结合起来，并分析了车桥耦合下利用测试车信号进行结构损伤识别的可行性进行了探讨，促进了一类新的损伤识别研究方法，即不利用结构上直接测试的信号，而是利用车体上的间接信号进行结构检测评估，具有重大的理论价值和广阔的应用前景。