【作者】 王邦进；

【导师】 欧进萍；

【作者基本信息】 哈尔滨工业大学 ， 工程力学， 2007， 硕士

【摘要】 结构健康监测引起了国内外众多研究者的兴趣,成为土木工程、防灾减灾工程研究的热点。经过近年来的努力,结构健康监测技术已经从实验室走向了工程实践。基于监测信息的损伤信息提取、损伤识别与模型修正等研究方向成为健康监测系统研究的核心。本文主要围绕桥梁监测与检测技术及桥梁安全评定做了如下的一些研究工作:首先由设计资料建立了永和大桥的有限元模型,然后研究了基于灵敏度的模型修正技术。重点研究了直接搜索算法,指出了模式搜索算法由于搜索模式固定不变造成了搜索效率低下且容易收敛于不光滑的脊线。在其基础上,对模式搜索算法做了改进,提出了自适应模式搜索算法:利用在迭代过程中获得的函数值信息在迭代的过程中不断修正搜索模式,使得优化过程获得更快的收敛速度且收敛性更有所保证。然后编制了“自适应搜索算法”程序,对几个常用的函数做了测试,并将该算法应用于永和大桥的模型修正中。研究了该算法用于大型结构模型修正的计算速度、收敛情况并与人工免疫算法作了对比。研究了永和大桥的频率对一些重要参数的灵敏度。分析了动力子系统的监测数据,采用NExT法和特征系统实现法对永和桥进行了工作模态参数识别,并与频域分解法的分析结果作了对比。在实测模态、基准有限元模型及自适应模式搜索算法的基础上,研究了基于监测信息的有限元模型实时修正,建立了用于健康监测系统的基准有限元模型。此外,本文还利用光纤光栅具有绝对测量的优点,提出了采用光纤光栅测量混凝土结构钻芯取样过程中的回弹应变,再根据混凝土材料在反复荷载作用下的应力-应变关系,推算在役结构的应力状态。并进行了仿真和实验研究。更多还原

【Abstract】 Recently, structural health monitoring (SHM) attracts many researchers interesting both domestic and foreign and becomes one of the most hot topics in civil engineering and disaster prevention and mitigation engineering. The structural health monitoring technology has been used in the engineering practice except for laboratory study gradually. Damage identification, finite-element model (FEM) updating and other related technology become the most important research field. How rational and effective use of recorded datum is the key of the health monitoring system.In this paper, FEM updating of YongHe bridge are studied. The main point are as follows:Firstly, The FEM of Yonghe Bridge is built based on the design drawings and the model is updated by FEM updating technology base on sensitivity analysis. Note that The direct pattern search algorithm is inefficient and often converges to the undifferential ridge lines. This paper presents a new adaptive pattern search algorithm, which makes use of the object function values obtained in the iterations. The algorithm has solved some of these problems, which indicates that the convergence is fast and can be guaranteed.Secondly, the adaptive search algorithm is programmed and several functions are studied in order to test its performance. Then, the algorithm is applied to model updating of Yonghe Bridge. The computing speed and convergence are compared with the artificial immune algorithm. The sensitivity of frequencies to some important parameters is studied.Thirdly, the monitoring data of dynamic subsystem is studied and the modal parameters of this bridge are identified using natural excitation technology and eigensystem realization algorithm. The results are compared with those of frequency domain decomposition with peaks pick method. Based on the measured modal data, baseline FEM model and adaptive pattern search algorithm, the real time FEM model updating is realized.At last, making use of the absolute measurement of Fiber Bragg Grating, this paper presents that the rebound strain can be measured in the drilling core sampling process of reinforcement concrete structures using FBG. The stress state of structure in service can be revealed according to the constitutive relationships of concrete material subjected to repeated load. FEM simulation and laboratory experiments have been done.更多还原