本文選題：吊桿　切入點：損傷識別　出處：《武漢理工大學》2015年碩士論文

【摘要】：近年來,接連發(fā)生的中、下承式拱橋運營期安全事故中,由于吊桿損傷、斷裂等原因引起的占了絕大多數(shù),造成了重大的經(jīng)濟損失及人員傷亡,安全形勢非常嚴峻。但與之相對應的是,現(xiàn)階段吊桿的損傷識別及安全評定技術(shù)相對還比較落后,少數(shù)的無損檢測手段和基于測試參數(shù)的損傷識別方法,無論在工程實用性還是識別準確性上都遠遠沒有達到要求。因此,對中、下承式拱橋吊桿的損傷識別與安全評定研究有十分重要的理論意義和工程應用價值。本文以銅瓦門大橋為背景,采用中承式拱橋的有限元結(jié)構(gòu)計算體系,研究了吊桿損傷與索力變化之間的理論關(guān)系,導出了索力變化列陣與損傷程度列陣關(guān)系的矢量表達式。在修正后有限元模型的基礎(chǔ)上,對吊桿系進行損傷模擬,得到了中、下承式拱橋吊桿損傷與索力變化關(guān)系的一些基本特征,并利用上述基本特征,結(jié)合理論分析的成果,對吊桿損傷與索力變化的關(guān)系進行線性改造。進一步地,考慮測試誤差的影響,建立了新的吊桿損傷預測模型。結(jié)合上述吊桿損傷預測模型,將粒子群優(yōu)化算法(PSO)進行有針對性的改造。通過自編FORTRAN程序,解決了高維損傷向量的約束優(yōu)化問題,建立了一套基于PSO的中、下承式拱橋吊桿損傷識別算法,從而可借助索力測量結(jié)果確定受損吊桿的位置和數(shù)量,并輸出損傷程度信息。通過考慮多種損傷組合及不同程度誤差干擾工況下的數(shù)值試驗,表明該損傷識別方法具有較高的識別精度,并具有較好的魯棒性。論文最后利用銅瓦門大橋的實測索力資料對全橋吊桿進行損傷識別,給出了全橋38根吊桿的損傷預報結(jié)果。以此為基礎(chǔ),提出了一套基于現(xiàn)存安全系數(shù)的中、下承式拱橋吊桿安全狀況評定方法。該方法考慮了吊桿內(nèi)力修正及吊桿抗力折減,并參考我國中、下承式拱橋吊桿安全系數(shù)的發(fā)展歷史及現(xiàn)有的國家標準,制定了吊桿安全的分級評價準則,同時利用該方法對銅瓦門大橋進行了全面的吊桿安全評價。理論與實踐效果表明,本文所提出的吊桿損傷識別及安全狀況評定方法可以較好地描述吊桿現(xiàn)有的安全狀態(tài),且算法穩(wěn)定,使用方便,可以在一定程度上提高中、下承式拱橋養(yǎng)護作業(yè)的水平。
[Abstract]:In recent years, in successive safety accidents of through arch bridges during operation period, most of them were caused by the damage and fracture of suspenders, resulting in heavy economic losses and casualties. The safety situation is very serious. However, the damage identification and safety assessment techniques of the suspenders are relatively backward at the present stage. A few methods of nondestructive testing and damage identification based on test parameters are used. In terms of engineering practicability and recognition accuracy, the requirements are far from being met. The research on the damage identification and safety assessment of the suspenders of the through arch bridge is of great theoretical significance and engineering application value. In this paper, the finite element structure calculation system of the middle through arch bridge is adopted in the context of the Tongwamen Bridge. In this paper, the theoretical relationship between cable force and cable force is studied, and the vector expression of the relation between cable force change array and damage degree array is derived. Based on the modified finite element model, the damage simulation of suspender system is carried out. Some basic characteristics of the relationship between through arch bridge hanger damage and cable force change, and by using the above basic characteristics, combining with the results of theoretical analysis, the relationship between suspension damage and cable force change is linearly modified. Considering the influence of test error, a new damage prediction model of suspension rod is established. The particle swarm optimization (PSO) algorithm is modified by combining the above damage prediction model of suspenders. The constrained optimization problem of high dimensional damage vector is solved, and a set of damage identification algorithm based on PSO for middle through arch bridge suspension is established. The position and number of damaged suspenders can be determined by the result of cable force measurement. The damage degree information is outputted. The numerical experiments under various damage combinations and different degree of error interference conditions show that the damage identification method has a high accuracy. Finally, using the measured cable force data of Tongwamen Bridge to identify the damage of the suspension rod of the whole bridge, the damage prediction results of 38 suspenders of the whole bridge are given. Based on the existing safety factor, a method for evaluating the safety of the suspenders of the through arch bridge is presented. The method takes into account the modification of the internal force of the suspenders and the reduction of the resistance of the suspenders, and refers to our country. The development history of through arch bridge suspender safety factor and the existing national standard, and the grading evaluation criteria of the suspender safety are established. At the same time, the comprehensive safety evaluation of the suspension rod of Tonghuamen Bridge is carried out by using this method. The theoretical and practical results show that, The method proposed in this paper can describe the existing safety state of the suspender, and the algorithm is stable and easy to use, which can improve the maintenance level of the through arch bridge to a certain extent.
【學位授予單位】：武漢理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U446;U448.22

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本文編號：1666914