基于小波分析的造船用龙门吊损伤识别研究

发布时间：2018-02-15 08:27

本文关键词： 损伤识别龙门吊小波变换时-频分析长标距应变传感位移模态　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着中国港口和造船业的迅速发展,造船用龙门吊数量日益增加。高荷载量和恶劣环境致使龙门吊在寿命周期内产生的积累损伤成为诱发其安全事故的重要因素。龙门吊结构体系庞大、工作荷载高,其安全事故将对人身安全和经济发展产生严重的危害。结构损伤识别技术可以准确地识别结构的损伤信息,为结构的及时修复与加固提供有利条件,从而保证其安全性。鉴于此,论文以造船用龙门吊主体结构损伤为研究对象,基于小波分析,通过理论分析、数值模拟和模型试验对小波损伤识别方法进行了以下研究：(1)对比现有结构损伤识别方法,分析了小波方法在识别结构损伤中的优点,揭示了小波函数特性对结构损伤信息提取的影响,明确了选择小波函数的基本原则。(2)采用基于小波变换提取结构模态奇异点的方法识别结构损伤。基于有限元方法分别对具有单点和多点损伤的梁、单层构架和缩尺龙门吊结构进行动力分析,根据其位移与加速度信号提取结构模态信息,并且利用小波变换识别了结构损伤导致的模态信息中的奇异点。(3)分析了长标距应变信号对损伤的敏感性,提出了基于修正小波包能量分析的损伤识别方法。采用有限元方法模拟了不同结构的应变时程数据,根据提取的损伤指标进行了损伤识别。结果表明,修正小波包能量变化率可以准确的识别损伤的位置,较为准确的识别结构的损伤程度,且对信号中的噪声具有较好的鲁棒性。(4)通过简支钢梁的试验分析,得出了较为准确的损伤程度信息,证明了修正小波包能量变化率作为结构损伤指标的可行性。总之,论文通过理论分析、数值模拟和模型试验对提出的小波损伤识别方法进行了研究,提出了基于长标距应变传感和系统模态识别的龙门吊主体结构损伤的识别方法,通过简支钢梁的试验分析验证了该方法的可靠性与精确性,研究结果为龙门吊损伤识别提供了新的思路和方法,也为龙门吊结构健康监测系统的搭建提供了新的支持。
[Abstract]:With the rapid development of China's port and shipbuilding industry, The number of gantry cranes for shipbuilding is increasing day by day. The accumulative damage caused by high load and bad environment becomes an important factor to induce safety accidents of gantry cranes. The structure system of gantry cranes is large and the working load is high. The structural damage identification technology can accurately identify the damage information of the structure and provide favorable conditions for the timely repair and reinforcement of the structure. So as to ensure its safety. In view of this, the main structure damage of shipbuilding gantry crane is taken as the research object, based on wavelet analysis, through theoretical analysis, Numerical simulation and model test are used to study the wavelet damage identification method. (1) comparing with the existing structural damage identification methods, the advantages of wavelet method in structural damage identification are analyzed. The influence of wavelet function characteristics on structure damage information extraction is revealed. The basic principle of selecting wavelet function is defined. (2) the method of extracting structural modal singularity points based on wavelet transform is used to identify structural damage. Dynamic analysis of single-layer frame and telescopic gantry crane structure is carried out, and modal information of the structure is extracted according to its displacement and acceleration signals. Using wavelet transform to identify the singularity point in the modal information caused by structural damage, the sensitivity of the long distance strain signal to the damage is analyzed. The damage identification method based on modified wavelet packet energy analysis is proposed. The strain time history data of different structures are simulated by finite element method, and the damage identification is carried out according to the damage index extracted. The results show that, The modified wavelet packet energy change rate can accurately identify the damage location and the damage degree of the structure, and has good robustness to the noise in the signal. More accurate damage degree information is obtained, and the feasibility of using modified wavelet packet energy change rate as structural damage index is proved. The method of wavelet damage identification is studied by numerical simulation and model test. The damage identification method of the main structure of gantry crane based on long distance strain sensing and system modal identification is proposed. The reliability and accuracy of the method are verified by the test analysis of simply supported steel beam. The results provide a new idea and method for the damage identification of gantry crane and a new support for the construction of health monitoring system of gantry crane structure.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U673.38

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