本文選題：方差貢獻率 + 泄流結(jié)構(gòu)��； 參考：《南昌大學(xué)》2014年碩士論文

【摘要】：泄流結(jié)構(gòu)的模態(tài)參數(shù)識別與動力損傷診斷是近20年來研究熱點，頻率和振型為結(jié)構(gòu)動力損傷診斷的兩大整體損傷因子，，其中結(jié)構(gòu)的固有頻率是最易測得的動力參數(shù)。多測點泄流結(jié)構(gòu)模態(tài)識別中，由于不同測點的振動信號頻率成分和噪聲水平不盡相同，結(jié)構(gòu)固有頻率識別結(jié)果僅能精確到一定區(qū)間范圍，而不是一個準確值，這不利于基于頻率（或與頻率有關(guān)的損傷因子）變化的動力損傷診斷。數(shù)據(jù)級信息融合技術(shù)可根據(jù)一定的理論規(guī)則將多個信號融合為一個更加貼近真實值的信號。信息融合技術(shù)在結(jié)構(gòu)工程中的應(yīng)用尚處于信號模擬的初步探索階段，為提供準確、全面的振動信號，實現(xiàn)泄流結(jié)構(gòu)模態(tài)頻率的準確識別，本文主要研究了以下內(nèi)容： （1）針對傳統(tǒng)數(shù)據(jù)融合算法對信號相似度要求高以及固定融合系數(shù)的缺陷，本文提出了基于方差貢獻率的泄流結(jié)構(gòu)動態(tài)響應(yīng)數(shù)據(jù)融合算法。并通過數(shù)值模擬的方式，從三個方面（準確性、全面性以及密頻結(jié)構(gòu)融合）探討了基于方差貢獻率的泄流結(jié)構(gòu)動態(tài)融合算法的可行性，并以蜀河閘墩結(jié)構(gòu)、二灘拱壩及信江樞紐泄流閘墩的原型觀測數(shù)據(jù)驗證了該算法的可行性。研究表明：該算法能夠有效利用不同測點信號的相關(guān)性、互補性和冗余性，使融合后信號具有結(jié)構(gòu)整體振動特性，其動態(tài)融合模式較傳統(tǒng)加權(quán)融合算法更加靈活。 （2）研究了基于概率密度函數(shù)的泄流結(jié)構(gòu)諧波響應(yīng)模態(tài)剔除方法。多測點模態(tài)識別難以分辨信號中的結(jié)構(gòu)響應(yīng)與諧波響應(yīng)，針對泄流結(jié)構(gòu)振動響應(yīng)中混入的諧波信號（如兼發(fā)電與泄流的河床式水電站發(fā)電機組運轉(zhuǎn)產(chǎn)生的諧波信號），基于方差貢獻率的泄流結(jié)構(gòu)多測點動態(tài)響應(yīng)融合算法具有較強的信息提取能力，無法剔除原測點混入的諧波響應(yīng)，常規(guī)去噪方法亦無法將其剔除�；诟怕拭芏群瘮�(shù)的泄流結(jié)構(gòu)諧波響應(yīng)模態(tài)剔除方法從統(tǒng)計學(xué)的角度分析諧波響應(yīng)與結(jié)構(gòu)響應(yīng)的差別，先對多測點信號頻域分解，再基于概率密度函數(shù)擬合各個頻率成分的振動信號，最后通過模擬一組結(jié)構(gòu)響應(yīng)與諧波響應(yīng)的混合信號研究了該方法的可行性，并且通過預(yù)先在某泄流結(jié)構(gòu)原型觀測信號中加入諧波信號研究其識別效果，結(jié)果表明：該方法簡單而實用。
[Abstract]:Identification of modal parameters and dynamic damage diagnosis of discharge structures have been a hot research topic in recent 20 years. Frequency and mode type are the two major global damage factors for dynamic damage diagnosis of structures, and the natural frequencies of structures are the most easily measured dynamic parameters. In modal identification of multi-point discharge structure, due to the different frequency components and noise levels of vibration signals at different measuring points, the identification results of natural frequencies of structures can only be accurate within a certain range, not an accurate value. This is not conducive to dynamic damage diagnosis based on changes in frequency (or frequency-related damage factors). Data level information fusion technology can fuse multiple signals into a signal closer to the real value according to certain theoretical rules. The application of information fusion technology in structural engineering is still in the initial exploration stage of signal simulation. In order to provide accurate and comprehensive vibration signal and realize accurate identification of modal frequency of discharge structure, this paper mainly studies the following contents: 1) aiming at the shortcomings of the traditional data fusion algorithm which requires high similarity and fixed fusion coefficient, a dynamic response data fusion algorithm based on variance contribution rate is proposed in this paper. Through numerical simulation, the feasibility of dynamic fusion algorithm of discharge structure based on variance contribution rate is discussed from three aspects (accuracy, comprehensiveness and dense frequency structure fusion), and the structure of Shuhe sluice pier is used. The prototype observation data of discharge pier of Ertan Arch Dam and Xinjiang River Project verify the feasibility of the algorithm. The results show that the proposed algorithm can effectively utilize the correlation, complementarity and redundancy of different measurement points, and make the fusion signal have the whole vibration characteristics of the structure. The dynamic fusion mode is more flexible than the traditional weighted fusion algorithm. (2) the method of eliminating harmonic response modal of leakage structure based on probability density function is studied. It is difficult to distinguish the structural response from the harmonic response in the multi-point modal identification. Aiming at the harmonic signals in the vibration response of discharge structure (such as the harmonic signal generated by generating and discharging generating units of river bed hydropower station), the fusion algorithm of dynamic response of multiple measuring points of discharge structure based on variance contribution rate is presented. Has a strong ability to extract information, The harmonic response of the original measurement point can not be eliminated, nor can the conventional denoising method. Based on probability density function, the method of eliminating harmonic response modal of leakage structure is presented. The difference between harmonic response and structural response is analyzed from the point of view of statistics, and the frequency domain decomposition of multi-point signal is carried out. Then the vibration signals of various frequency components are fitted based on the probability density function. Finally, the feasibility of the method is studied by simulating a set of mixed signals of structural response and harmonic response. The recognition effect of harmonic signal is studied by adding harmonic signal into the prototype observation signal of a discharge structure in advance. The results show that the method is simple and practical.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TV31

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