本文選題：葉片裂紋 + 異常振動(dòng)�。� 參考：《國防科學(xué)技術(shù)大學(xué)》2012年碩士論文

【摘要】：高速旋轉(zhuǎn)葉片是燃?xì)廨啓C(jī)中的關(guān)鍵部件，長期工作在高溫、高壓、大應(yīng)力等惡劣環(huán)境下，且承受離心力、氣動(dòng)力等動(dòng)載荷作用，容易產(chǎn)生振動(dòng)。各種異常振動(dòng)是造成葉片損傷或故障的主要原因，因此在線檢測高速旋轉(zhuǎn)葉片的異常振動(dòng)具有重要意義。為此，本文針對(duì)常見的葉片裂紋故障，以簡化葉盤為研究對(duì)象，開展了基于葉端定時(shí)原理的高速旋轉(zhuǎn)葉片振動(dòng)信號(hào)非接觸在線檢測與裂紋故障診斷方法研究。主要工作包括： （1）為了分析裂紋對(duì)葉片振動(dòng)行為的影響，，利用Euler-Bernoulli梁理論建立了含裂紋葉片的動(dòng)力學(xué)模型，推導(dǎo)了其動(dòng)頻表達(dá)式，并建立有限元模型進(jìn)行了仿真驗(yàn)證。結(jié)果表明：裂紋導(dǎo)致葉片動(dòng)頻減小、振幅增大，并且越靠近葉片根部，影響越大； （2）推導(dǎo)了利用3個(gè)葉端定時(shí)傳感器的高速旋轉(zhuǎn)葉片振動(dòng)位移表達(dá)式，并針對(duì)其具有欠采樣的特點(diǎn)，研究了基于香農(nóng)采樣定理的信號(hào)重構(gòu)方法和基于平滑的振動(dòng)信號(hào)預(yù)處理方法，為后續(xù)葉片裂紋特征提取和故障診斷提供了數(shù)據(jù)基礎(chǔ)； （3）分別研究了欠采樣信號(hào)下基于余數(shù)定理的葉片振動(dòng)頻率提取方法、重構(gòu)信號(hào)下基于狀態(tài)空間模型的葉片模態(tài)頻率提取方法，并在此基礎(chǔ)上研究了基于模態(tài)局域化的葉片裂紋故障診斷方法，可有效識(shí)別不同的裂紋狀態(tài)； （4）設(shè)計(jì)了高速旋轉(zhuǎn)葉片實(shí)驗(yàn)臺(tái)，搭建了葉片振動(dòng)信號(hào)非接觸在線檢測系統(tǒng)，通過人為方式注入葉片裂紋，對(duì)所研方法進(jìn)行了實(shí)驗(yàn)驗(yàn)證； 結(jié)果表明，本文所研方法可在線識(shí)別高速旋轉(zhuǎn)葉片的異常振動(dòng)、檢測不同程度的裂紋故障，可有望用于燃?xì)廨啓C(jī)轉(zhuǎn)子葉片狀態(tài)的在線監(jiān)測。
[Abstract]:High speed rotating blade is the key component of gas turbine. It works in high temperature, high pressure and high stress for a long time, and it is easy to produce vibration under the action of centrifugal force, aerodynamic force and other dynamic loads. Various abnormal vibration is the main cause of blade damage or fault, so it is very important to detect the abnormal vibration of high-speed rotating blade online. For this reason, aiming at the common blade crack faults and taking the simplified blade disk as the research object, the method of non-contact on-line detection and crack fault diagnosis of high-speed rotating blade vibration signal based on the principle of blade tip timing is studied in this paper. The main works are as follows: (1) in order to analyze the effect of crack on blade vibration behavior, the dynamic model of blade with crack is established by using Euler-Bernoulli beam theory, the dynamic frequency expression is deduced, and the finite element model is established to verify the dynamic behavior. The results show that the crack reduces the dynamic frequency and increases the amplitude of the blade, and the closer the blade is to the root, the greater the effect. (2) the vibration displacement expression of high-speed rotating blade using three tip timing sensors is derived. The signal reconstruction method based on Shannon sampling theorem and the vibration signal preprocessing method based on smoothing are studied in order to provide the data basis for the crack feature extraction and fault diagnosis of the subsequent blade. (3) the extraction method of blade vibration frequency based on remainder theorem in under-sampled signal and the modal frequency extraction method based on state space model in reconstructed signal are studied respectively. On the basis of this, the fault diagnosis method of blade crack based on modal localization is studied, which can effectively identify different crack states. (4) A high-speed rotating vane experiment bench is designed. A non-contact on-line detection system for blade vibration signal is built. The method is experimentally verified by artificial injection of blade cracks. The results show that, The method proposed in this paper can identify the abnormal vibration of high speed rotating blades and detect crack faults of different degrees on line, which is expected to be used in the on-line monitoring of rotor blade condition of gas turbine.
【學(xué)位授予單位】：國防科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：TH165.3

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