【摘要】：起重機(jī)回轉(zhuǎn)支承工作環(huán)境惡劣，裂紋難以避免。目前，針對(duì)旋轉(zhuǎn)機(jī)械發(fā)展較為成熟的振動(dòng)診斷法對(duì)低速重載回轉(zhuǎn)支承裂紋難以實(shí)現(xiàn)有效檢測。裂紋發(fā)生部位通常較為隱蔽，常規(guī)巡檢與在線檢測技術(shù)難以有效發(fā)現(xiàn)。針對(duì)起重機(jī)回轉(zhuǎn)支承在故障診斷特別是早期故障診斷領(lǐng)域所面臨的難點(diǎn)問題，，本論文通過對(duì)早期裂紋形成機(jī)理、聲發(fā)射信號(hào)傳播規(guī)律及常用材料聲發(fā)射特性進(jìn)行分析，探討采用聲發(fā)射技術(shù)對(duì)回轉(zhuǎn)支承進(jìn)行裂紋檢測時(shí)聲源定位和嚴(yán)重程度識(shí)別等方面的問題。論文研究內(nèi)容主要包括： （1）裂紋形成機(jī)理及聲發(fā)射檢測可行性分析。利用疲勞接觸理論研究了回轉(zhuǎn)支承裂紋形成機(jī)理及裂紋擴(kuò)展形式，并在彈性波動(dòng)理論及聲發(fā)射檢測基本原理的基礎(chǔ)上，分析了利用聲發(fā)射技術(shù)對(duì)回轉(zhuǎn)支承裂紋進(jìn)行檢測的可行性。 （2）聲發(fā)射信號(hào)傳播規(guī)律及常用材料聲發(fā)射特性研究。運(yùn)用顯式算法在ANSYS/LS-DYNA中建立了聲發(fā)射信號(hào)傳播模型，研究聲發(fā)射信號(hào)在回轉(zhuǎn)支承套圈中傳播時(shí)傳播路徑、動(dòng)力響應(yīng)、能量衰減等規(guī)律；利用拉伸試驗(yàn)和三點(diǎn)彎曲試驗(yàn)對(duì)起重機(jī)回轉(zhuǎn)支承常用材料的聲發(fā)射特性進(jìn)行了試驗(yàn)研究。 （3）基于聲發(fā)射技術(shù)的裂紋源定位及嚴(yán)重程度識(shí)別。建立了基于線性時(shí)差的回轉(zhuǎn)支承裂紋源定位方法，采用平滑偽Wigner-Ville分布對(duì)閾值時(shí)差估計(jì)法進(jìn)行了修正，對(duì)定位效果進(jìn)行了模擬試驗(yàn)驗(yàn)證；利用從拉伸試驗(yàn)全過程中獲取到的聲發(fā)射波形信號(hào)，建立了基于小波包能量譜和支持向量機(jī)的聲發(fā)射信號(hào)嚴(yán)重程度識(shí)別模型。 （4）回轉(zhuǎn)支承裂紋檢測試驗(yàn)研究及工程應(yīng)用研究。在起重機(jī)回轉(zhuǎn)支承結(jié)構(gòu)健康檢測試驗(yàn)平臺(tái)上進(jìn)行了回轉(zhuǎn)支承裂紋檢測試驗(yàn)研究，驗(yàn)證了聲發(fā)射檢測在回轉(zhuǎn)支承裂紋檢測方面的可行性及準(zhǔn)確性。在此基礎(chǔ)上開展了起重機(jī)回轉(zhuǎn)支承裂紋檢測的工程應(yīng)用研究。
[Abstract]:The working environment of the crane slewing support is bad, and the crack is difficult to avoid. At present, it is difficult to detect the crack of low speed heavy load slewing bearing by vibration diagnosis method which is mature for rotating machinery. The location of cracks is usually concealed, and it is difficult to find the conventional inspection and on-line detection techniques. Aiming at the difficult problems of crane slewing bearing in the field of fault diagnosis, especially in the field of early fault diagnosis, this paper analyzes the mechanism of early crack formation, the propagation law of acoustic emission signal and the characteristics of acoustic emission of common materials. In this paper, acoustic emission technology is used to detect the crack of rotary bearing. The problems of sound source location and severity identification are discussed. The main contents of this paper are as follows: (1) the mechanism of crack formation and feasibility analysis of acoustic emission detection. Based on the theory of elastic wave and the basic principle of acoustic emission detection, the mechanism of crack formation and crack propagation in slewing bearing are studied by using fatigue contact theory. The feasibility of using acoustic emission technology to detect cracks in rotary bearing is analyzed. (2) the propagation law of acoustic emission signal and the characteristics of acoustic emission of common materials are studied. The acoustic emission signal propagation model in ANSYS/LS-DYNA is established by using explicit algorithm. The propagation path, dynamic response and energy attenuation of acoustic emission signal propagating in the ring of slewing bearing are studied. The acoustic emission characteristics of the materials commonly used in crane slewing support are studied by tensile test and three-point bending test. (3) crack source location and severity identification based on acoustic emission technology. A method for locating crack source of slewing bearing based on linear time difference is established. The method of threshold time difference estimation is modified by using smooth pseudo-Wigner-Ville distribution, and the localization effect is verified by simulation test. Using the acoustic emission waveform obtained from the whole process of the tensile test, The acoustic emission signal severity recognition model based on wavelet packet energy spectrum and support vector machine is established. (4) the experimental research and engineering application research on crack detection of slewing bearing. The crack detection of slewing bearing is studied on the health test platform of crane slewing bearing structure, and the feasibility and accuracy of acoustic emission detection in the detection of slewing bearing crack are verified. On this basis, the engineering application research of crane slewing bearing crack detection is carried out.
【學(xué)位授予單位】：華南理工大學(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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本文編號(hào)：2213608