本文關(guān)鍵詞： 損傷識(shí)別 龍門吊 小波變換 時(shí)-頻分析 長標(biāo)距應(yīng)變傳感 位移模態(tài)　出處：《東南大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著中國港口和造船業(yè)的迅速發(fā)展,造船用龍門吊數(shù)量日益增加。高荷載量和惡劣環(huán)境致使龍門吊在壽命周期內(nèi)產(chǎn)生的積累損傷成為誘發(fā)其安全事故的重要因素。龍門吊結(jié)構(gòu)體系龐大、工作荷載高,其安全事故將對(duì)人身安全和經(jīng)濟(jì)發(fā)展產(chǎn)生嚴(yán)重的危害。結(jié)構(gòu)損傷識(shí)別技術(shù)可以準(zhǔn)確地識(shí)別結(jié)構(gòu)的損傷信息,為結(jié)構(gòu)的及時(shí)修復(fù)與加固提供有利條件,從而保證其安全性。鑒于此,論文以造船用龍門吊主體結(jié)構(gòu)損傷為研究對(duì)象,基于小波分析,通過理論分析、數(shù)值模擬和模型試驗(yàn)對(duì)小波損傷識(shí)別方法進(jìn)行了以下研究：(1)對(duì)比現(xiàn)有結(jié)構(gòu)損傷識(shí)別方法,分析了小波方法在識(shí)別結(jié)構(gòu)損傷中的優(yōu)點(diǎn),揭示了小波函數(shù)特性對(duì)結(jié)構(gòu)損傷信息提取的影響,明確了選擇小波函數(shù)的基本原則。(2)采用基于小波變換提取結(jié)構(gòu)模態(tài)奇異點(diǎn)的方法識(shí)別結(jié)構(gòu)損傷。基于有限元方法分別對(duì)具有單點(diǎn)和多點(diǎn)損傷的梁、單層構(gòu)架和縮尺龍門吊結(jié)構(gòu)進(jìn)行動(dòng)力分析,根據(jù)其位移與加速度信號(hào)提取結(jié)構(gòu)模態(tài)信息,并且利用小波變換識(shí)別了結(jié)構(gòu)損傷導(dǎo)致的模態(tài)信息中的奇異點(diǎn)。(3)分析了長標(biāo)距應(yīng)變信號(hào)對(duì)損傷的敏感性,提出了基于修正小波包能量分析的損傷識(shí)別方法。采用有限元方法模擬了不同結(jié)構(gòu)的應(yīng)變時(shí)程數(shù)據(jù),根據(jù)提取的損傷指標(biāo)進(jìn)行了損傷識(shí)別。結(jié)果表明,修正小波包能量變化率可以準(zhǔn)確的識(shí)別損傷的位置,較為準(zhǔn)確的識(shí)別結(jié)構(gòu)的損傷程度,且對(duì)信號(hào)中的噪聲具有較好的魯棒性。(4)通過簡支鋼梁的試驗(yàn)分析,得出了較為準(zhǔn)確的損傷程度信息,證明了修正小波包能量變化率作為結(jié)構(gòu)損傷指標(biāo)的可行性。總之,論文通過理論分析、數(shù)值模擬和模型試驗(yàn)對(duì)提出的小波損傷識(shí)別方法進(jìn)行了研究,提出了基于長標(biāo)距應(yīng)變傳感和系統(tǒng)模態(tài)識(shí)別的龍門吊主體結(jié)構(gòu)損傷的識(shí)別方法,通過簡支鋼梁的試驗(yàn)分析驗(yàn)證了該方法的可靠性與精確性,研究結(jié)果為龍門吊損傷識(shí)別提供了新的思路和方法,也為龍門吊結(jié)構(gòu)健康監(jiān)測(cè)系統(tǒng)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.
【學(xué)位授予單位】：東南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U673.38

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