【摘要】：自20世紀70年代以來，國內(nèi)橋梁建設工程取得了豐富的成果，很多復雜化、大型化的橋梁相繼問世。橋梁結構，作為一個地區(qū)交通網(wǎng)絡咽喉的重要建筑物，保障其結構的安全性和耐久性尤為重要。我國橋梁數(shù)量龐大，許多既有橋梁由于設計、施工、超載、自然腐蝕等原因，出現(xiàn)了不同程度的老化、破損、裂縫等現(xiàn)象。為保證這些橋梁有足夠的安全性繼續(xù)使用，需要監(jiān)測和評估橋梁結構的損傷狀態(tài)，，從而對橋梁結構進行相應的維修和加固，這個過程就是橋梁健康監(jiān)測和結構損傷識別。 橋梁健康監(jiān)測系統(tǒng)的核心內(nèi)容就是結構損傷識別。結構損傷的出現(xiàn)，表現(xiàn)為實際結構動力特性（固有頻率、振型模態(tài)參數(shù)等）發(fā)生改變。因此可以通過對結構動力特性參數(shù)的分析，判斷結構損傷出現(xiàn)的位置和程度。本文重點研究梁式結構由于損傷引起的固有頻率變化，并采用指紋分析的方法，研究結構的損傷定位問題。 論文首先對結構損傷識別進行概述，比較詳細地介紹了結構損傷識別的基本方法，著重對比分析了分別基于靜力測試和動力測試的損傷識別方法。 其次，介紹梁橋結構動力損傷識別方法，根據(jù)理論建立三種損傷識別頻率指紋，分別是頻率變化比、頻率變化平方比和正則化的頻率變化率。比較這三種指紋進行損傷識別的精準度，發(fā)現(xiàn)正則化的頻率變化率指紋單調(diào)性最好，結構損傷定位的效果也比較好。再單獨討論正則化頻率指紋的穩(wěn)定性，分析梁的損傷單元寬度對頻率指紋的影響，并以梁式結構為例，指出頻率指紋進行損傷定位的原則和步驟，并進行有限元模型驗證，表明正則化的頻率變化率指紋進行損傷定位的精度還是比較高的，值得一提的是，頻率指紋對結構對稱損傷的定位尚需附加其它識別條件。 然后，對基于動力特性的損傷識別方法中出現(xiàn)的誤差進行理論分析，探討了動力測試誤差、模型誤差以及算法中存在的數(shù)值計算誤差。并針對誤差來源分析介紹了三種誤差影響的減少方法。 最后，介紹了橋梁健康監(jiān)測系統(tǒng)，論述健康監(jiān)測系統(tǒng)的構成以及與結構損傷識別的關系，重點說明傳感器優(yōu)化布置在健康監(jiān)測系統(tǒng)中的意見以及發(fā)展前景。
[Abstract]:Since the 1970s, the domestic bridge construction project has made rich achievements, a lot of complex, large-scale bridges have come out one after another. Bridge structure, as an important building in regional traffic network, ensures the safety and durability of its structure. The number of bridges in China is huge, many of the existing bridges appear different degrees of aging, breakage and cracks due to the design, construction, overload, natural corrosion and other reasons. In order to ensure the safety of these bridges, it is necessary to monitor and evaluate the damage state of the bridge structure, so as to repair and strengthen the bridge structure. This process is the bridge health monitoring and structural damage identification. Structural damage identification is the core of bridge health monitoring system. The occurrence of structural damage is manifested by the change of the actual structural dynamic characteristics (natural frequency, modal parameters, etc.). Therefore, the location and extent of structural damage can be judged by analyzing the dynamic characteristic parameters of the structure. In this paper, the natural frequency change of beam structure caused by damage is studied, and the damage location of beam structure is studied by fingerprint analysis. Firstly, the paper summarizes the structural damage identification, introduces the basic methods of structural damage identification in detail, and analyzes the damage identification methods based on static test and dynamic test respectively. Secondly, the dynamic damage identification method of beam bridge structure is introduced. According to the theory, three kinds of damage identification frequency fingerprints are established, which are frequency change ratio, frequency change square ratio and regularization frequency change rate. Comparing the accuracy of damage identification with these three kinds of fingerprints, it is found that the frequency change rate of regularization is the best, and the effect of structural damage location is better. Then the stability of regularized frequency fingerprint is discussed separately, and the influence of damage element width of beam on frequency fingerprint is analyzed. Taking beam structure as an example, the principle and procedure of damage location by frequency fingerprint are pointed out, and the finite element model is verified. The results show that the accuracy of damage location by regularized frequency change rate fingerprint is still relatively high. It is worth mentioning that the frequency fingerprint has to attach other identification conditions to the location of structural symmetrical damage. Then, the errors in the damage identification method based on dynamic characteristics are analyzed theoretically, and the dynamic test error, model error and numerical calculation error in the algorithm are discussed. According to the error source analysis, three methods of reducing error influence are introduced. Finally, this paper introduces the bridge health monitoring system, discusses the constitution of the health monitoring system and the relationship between the health monitoring system and the structural damage identification, and emphasizes the views and development prospects of the optimal layout of the sensors in the health monitoring system.
【學位授予單位】：武漢理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U441.3;U446

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本文編號：2277634