【摘要】：當(dāng)結(jié)構(gòu)出現(xiàn)損傷時,對結(jié)構(gòu)的狀態(tài)進(jìn)行診斷和評估,以準(zhǔn)確識別出結(jié)構(gòu)的損傷位置和損傷程度,進(jìn)一步分析損傷出現(xiàn)的原因,這一過程的實現(xiàn)就是結(jié)構(gòu)損傷檢測。根據(jù)結(jié)構(gòu)損傷檢測報告,設(shè)計人員對結(jié)構(gòu)安全與否進(jìn)行評價,進(jìn)而提出對建筑結(jié)構(gòu)進(jìn)行維護(hù)加固的最佳方案,從而最大限度避免結(jié)構(gòu)安全事故的發(fā)生。梁結(jié)構(gòu)是工程中常見的一種結(jié)構(gòu)形式,是主體結(jié)構(gòu)的重要組成部分,廣泛應(yīng)用于建筑、市政、橋梁等工程領(lǐng)域。本文以梁為研究對象,采用無厚度的彈簧單元模擬梁結(jié)構(gòu)中出現(xiàn)的微小損傷。探索如何設(shè)置彈簧單元的相關(guān)參數(shù),才能使數(shù)值模型更加貼近工程實際。在損傷梁上施加移動荷載,得到損傷梁的動力特性。采集任意點瞬態(tài)響應(yīng)數(shù)據(jù)繪制位移時程曲線和加速度時程曲線。對時程曲線數(shù)據(jù)進(jìn)行分析和處理,以確定梁結(jié)構(gòu)的損傷位置�；趯p傷檢測問題相關(guān)文獻(xiàn)的學(xué)習(xí),本文從以下幾個方面展開研究:首先,通過建立梁結(jié)構(gòu)動力學(xué)方程以及對損傷梁進(jìn)行振動分析來研究移動荷載作用下?lián)p傷梁的力學(xué)性能�；谠摾碚�,在ANSYS軟件中建立移動荷載作用下的損傷梁模型,選擇彈簧單元模擬厚度可忽略不計的微小損傷,在梁上施加移動荷載,獲得不同損傷程度、不同荷載質(zhì)量、不同移動速度下的位移時程曲線和加速度時程曲線。其次,根據(jù)實驗室現(xiàn)有條件設(shè)計模型試驗。在試驗用梁模型上設(shè)置不同位置和不同程度的裂縫損傷,按照不同荷載質(zhì)量、不同移動速度、不同測點位置等工況進(jìn)行對比分析。最后,應(yīng)用去噪、小波變換等方法進(jìn)一步處理分析試驗和數(shù)值模擬所得的數(shù)據(jù),得到損傷的位置及各因素對檢測結(jié)果的影響。在損傷檢測中,施加的移動荷載質(zhì)量越大,速度越小;被檢測的損傷程度越大;損傷位置距離測點越近時,檢測效果越明顯。對于同種工況和同種檢測條件下,加速度時程曲線比位移時程曲線的檢測效果明顯。原本看不出損傷的位移時程曲線,經(jīng)過小波變換后,在損傷位置處尺度大于某個值時光斑變得較明顯,選取其中一個尺度的小波變換圖,可以在損傷處發(fā)現(xiàn)明顯凸起,可以成功檢測出損傷。以上有關(guān)移動荷載作用下梁結(jié)構(gòu)損傷檢測的研究,對后續(xù)其他類型結(jié)構(gòu)研究具有一定參考價值。
[Abstract]:When the structure is damaged, the state of the structure is diagnosed and evaluated, in order to accurately identify the damage location and damage degree of the structure, and further analyze the cause of the damage, the realization of this process is structural damage detection. According to the structural damage detection report, the designer evaluates the safety of the structure, and then puts forward the best plan for the maintenance and reinforcement of the building structure, thus avoiding the occurrence of the structural safety accident to the maximum extent. Beam structure is a common structural form in engineering and an important part of the main structure. It is widely used in the construction, municipal, bridge and other engineering fields. In this paper, a thickness-free spring element is used to simulate the small damage in beam structure. In order to make the numerical model more close to the engineering practice, this paper explores how to set the relevant parameters of the spring element. The dynamic characteristics of the damaged beam are obtained by applying moving load on the damaged beam. The transient response data of any point are collected to draw the displacement time history curve and acceleration time history curve. The time history curve data are analyzed and processed to determine the damage location of the beam structure. Based on the study of the related literature on damage detection, this paper studies the following aspects: firstly, the mechanical properties of the damaged beam under moving load are studied by establishing the dynamic equation of the beam structure and analyzing the vibration of the damaged beam. Based on this theory, the damage beam model under moving load is established in ANSYS software, and the spring element is selected to simulate the small damage with negligible thickness, and the moving load is applied to the beam to obtain different damage degree and different load quality. Displacement time history curve and acceleration time history curve under different moving velocity. Secondly, the model test is designed according to the existing conditions in the laboratory. Different positions and different degree of crack damage are set on the beam model of the test, and compared and analyzed according to different load mass, different moving speed, different measuring point position and so on. Finally, the data obtained from the experiment and numerical simulation are processed by denoising and wavelet transform, and the location of the damage and the influence of various factors on the detection results are obtained. In damage detection, the larger the mass of moving load is, the smaller the speed is; the greater the degree of damage is detected; the closer the damage position is to the measuring point, the more obvious the detection effect is. For the same working conditions and the same detection conditions, the acceleration time history curve is more effective than the displacement time history curve. The displacement time history curve of the damage could not be seen originally. After wavelet transform, the spot became more obvious when the scale of the damage was larger than a certain value, and the wavelet transform diagram of one of the scales could find the obvious protruding at the damage place. Damage can be detected successfully. The above research on damage detection of beam structure under moving load has some reference value for other kinds of structures.
【學(xué)位授予單位】：山東農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU317

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本文編號：2419091