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機(jī)電工程學(xué)院 畢業(yè)設(shè)計(jì)外文資料翻譯 設(shè)計(jì)題目: JD1041載貨汽車(chē)變速器及傳動(dòng)軸設(shè)計(jì) 譯文題目: 汽車(chē)變速箱故障診斷之噪聲測(cè)量 學(xué)生姓名： 學(xué) 號(hào)： 專(zhuān)業(yè)班級(jí)： 指導(dǎo)教師： 正文：外文資料譯文 附 件：外文資料原文 指導(dǎo)教師評(píng)語(yǔ)： 譯文基本順暢、正確，專(zhuān)業(yè)內(nèi)容理解和翻譯基本符合原文，達(dá)到要求。 簽名：張?jiān)掠?016 年 4 月 6 日 外文資料譯文（出處：能源和環(huán)境國(guó)際期刊） 汽車(chē)變速箱故障診斷之噪聲測(cè)量 Sameh M. Metwalley, Nabil Hammad, Shawki A. Abouel-Seoud 哈勒旺大學(xué)工學(xué)院，埃及開(kāi)羅 摘要 噪聲測(cè)量是許多健康監(jiān)測(cè)和診斷旋轉(zhuǎn)機(jī)器技術(shù)之一，例如變速箱。雖然關(guān)于理解潛在噪音測(cè)量監(jiān)控變速箱的重要研究一直在進(jìn)行，但這只應(yīng)用于任何類(lèi)型的齒輪(正齒齒輪，螺旋等等)。實(shí)驗(yàn)室規(guī)模的狀態(tài)監(jiān)測(cè)、單級(jí)齒輪箱，代表了汽車(chē)真正的齒輪箱，使用非破壞性檢驗(yàn)方法獲得的處理波形與先進(jìn)的信號(hào)處理技術(shù)是當(dāng)前工作的目的。聲發(fā)射是用于這一目的。實(shí)驗(yàn)裝置和儀器存在于細(xì)節(jié)。重點(diǎn)給出了通過(guò)噪聲測(cè)量信號(hào)的處理來(lái)提取傳統(tǒng)以及小說(shuō)從監(jiān)測(cè)波形參數(shù)可能的診斷價(jià)值。參數(shù)的進(jìn)化特性和測(cè)試時(shí)間選擇,突出顯示評(píng)估和參數(shù)是最有趣的診斷行為。目前的工作還反應(yīng)了包括長(zhǎng)期(0--6.0小時(shí))實(shí)驗(yàn)叛逃齒輪系統(tǒng)的結(jié)果,橫向削減范圍從0.75毫米到3.0毫米模擬牙齒裂縫。不同的參數(shù)記錄來(lái)自聲發(fā)射的信號(hào)相關(guān)的分析,探討其診斷價(jià)值狀態(tài)監(jiān)測(cè)系統(tǒng)的發(fā)展。 版權(quán)?2011年國(guó)際能源和環(huán)境基礎(chǔ),保留所有權(quán)利。 關(guān)鍵詞:診斷、齒輪傳動(dòng)系統(tǒng)、聲壓級(jí),平穩(wěn)信號(hào),故障設(shè)備,測(cè)量設(shè)備,裝備條件、監(jiān)控、維護(hù)行動(dòng)。 1、介紹 聲發(fā)射是指范圍導(dǎo)致結(jié)構(gòu)傳遞的生成和fluid-borne(液體、氣體)傳播波由于快速釋放來(lái)源于材料表面或局部的能量的現(xiàn)象。聲發(fā)射技術(shù)在研究和工業(yè)的應(yīng)用是證據(jù)確鑿的。關(guān)于變速箱，幾個(gè)調(diào)查人員評(píng)估了應(yīng)用聲發(fā)射技術(shù)于診斷和預(yù)后。其他的應(yīng)用在聲發(fā)射檢測(cè)在直齒圓柱齒輪彎曲疲勞多指出聲發(fā)射比振動(dòng)裂紋擴(kuò)展和剛度測(cè)量更敏感。同樣,AE被發(fā)現(xiàn)比振動(dòng)分析表面破壞的規(guī)模更敏感。 2、平穩(wěn)信號(hào)數(shù)據(jù)分析 文獻(xiàn)中機(jī)械的故障診斷系統(tǒng)有許多信號(hào)處理技術(shù)。Case-dependent知識(shí)和調(diào)查需要選擇合適的信號(hào)處理工具。在條件最常見(jiàn)的是波形數(shù)據(jù)監(jiān)測(cè)振動(dòng)信號(hào)和聲學(xué)排放。其他超聲信號(hào)波形數(shù)據(jù),電動(dòng)機(jī)電流、局部放電等。在文獻(xiàn)中,有兩個(gè)主要類(lèi)別的固定波形數(shù)據(jù)分析，時(shí)域分析和頻域分析。 3、時(shí)域分析 時(shí)域分析是直接基于波形本身的時(shí)間計(jì)算特征的描述性統(tǒng)計(jì)如波形信號(hào)。傳統(tǒng)的時(shí)域分析的意思是峰間隔,標(biāo)準(zhǔn)差,波峰因素和高階統(tǒng)計(jì)量(均方根,偏態(tài)、峰態(tài)等)。這些特性通常稱(chēng)為時(shí)域特性。一個(gè)受歡迎的時(shí)域分析方法是時(shí)間同步平均(TSA)。TSA的想法是使用原始信號(hào)的演進(jìn)統(tǒng)計(jì)平均值,以消除或減少噪音和影響。 更先進(jìn)的方法是時(shí)域波形數(shù)據(jù)分析應(yīng)用時(shí)間序列模型，時(shí)間序列模型的主要思想是適應(yīng)波形數(shù)據(jù)參數(shù)模型和提取時(shí)間基于該參數(shù)模型特性。流行的模型在文獻(xiàn)中使用汽車(chē)回歸(AR)模型和汽車(chē)回歸移動(dòng)平均(ARMA)模型。 在本文中,只有高階統(tǒng)計(jì)量的均方根(RMS)。這個(gè)功能通常被稱(chēng)為時(shí)域特性。RMS是一種平均的信號(hào),對(duì)于離散信號(hào),RMS值定義為： 4、頻域分析 頻域分析是基于轉(zhuǎn)換后的信號(hào)。頻域分析比時(shí)域分析的優(yōu)勢(shì)是能夠輕易識(shí)別和隔離某些感興趣的頻率成分。最廣泛使用的光譜分析是傅里葉變換(FFT)的意思。頻譜分析的主要思想是看看整個(gè)光譜或仔細(xì)看看感興趣的某些頻率成分,從而提取特征信號(hào)。 5、常數(shù)比例帶寬(CPB) 基本常數(shù)之間的選擇,絕對(duì)帶寬和恒定的比例(百分比)帶寬是一個(gè)固定的百分比調(diào)中心頻率。常數(shù)比例帶寬用統(tǒng)一的標(biāo)準(zhǔn)決議一個(gè)線(xiàn)性頻率刻度,這例如,以相同的分辨率和諧波相關(guān)組件,分離促進(jìn)檢測(cè)諧波模式。然而,線(xiàn)性頻率刻度制約了有用的頻率范圍的限制(最)二十年。 值得特別重視的兩個(gè)特殊類(lèi)型的常數(shù)比例帶寬濾波器,即八度和第三個(gè)八度過(guò)濾器。因?yàn)檫@些被廣泛使用,尤其是聲學(xué)測(cè)量。這樣的上極限頻率通常是兩倍有限的頻率較低,導(dǎo)致70.0%的帶寬。 6、測(cè)量系統(tǒng)和測(cè)試過(guò)程 圖1：實(shí)驗(yàn)裝置 圖2：B&K便攜式多通道脈沖 圖3：B&K脈沖labshop 圖4：齒裂現(xiàn)象 圖1顯示了用于齒輪箱測(cè)試的實(shí)驗(yàn)裝置。齒輪箱由兩個(gè)2毫米,壓力角20°,64和26個(gè)牙齒,寬40毫米的螺旋齒輪模塊。齒輪的軸是由兩個(gè)球軸承支持。為了確保適當(dāng)?shù)臐?rùn)滑，整個(gè)系統(tǒng)是固定在一個(gè)油池中。變速器是由一個(gè)電動(dòng)馬達(dá)和電力液壓盤(pán)式制動(dòng)器,而速度是衡量照片電探針。布魯&卡亞爾:(b和k)便攜式多通道脈沖型3560 - b - x05(圖2)與冷凝器1/2 -麥克風(fēng)和前置放大器類(lèi)型4189 - 4189在變速箱前殼的中心位置遠(yuǎn)離套管和地面分別由1.0米和0.50米。b和k脈沖labshop是測(cè)量軟件使用7700型分析結(jié)果(圖3)。各種參數(shù)進(jìn)化在測(cè)試期間——從一個(gè)代表性的測(cè)試裝置系統(tǒng)根厚度的減少模擬齒裂紋(圖4)將和詳細(xì)的研究。許多測(cè)試進(jìn)行相同的配置行為產(chǎn)生類(lèi)似的參數(shù)。人為地用鐵絲電火花加工齒輪的齒的根源來(lái)創(chuàng)建一個(gè)壓力濃度,最終導(dǎo)致了傳播裂紋。裂縫深度范圍從0.75毫米到3.0毫米，厚度幾乎0.5毫米。錄音每15分鐘被收錄,總共24段錄音(0--6.0 h測(cè)試時(shí)間),直到終止測(cè)試。這種類(lèi)型的測(cè)試首選是為了有機(jī)會(huì)監(jiān)視浴破壞模式,即自然裂縫傳播。損害是保證通過(guò)增加測(cè)試周期的剩余的金屬的地方牙區(qū)域有足夠的壓力在塑性變形區(qū)域。仔細(xì)監(jiān)測(cè)SPL反應(yīng)揭示了一些微妙的變化和增加反應(yīng)。在最初的幾小時(shí)，或者“磨合期”，當(dāng)減小負(fù)載,所有的反應(yīng)都略有下降。磨合期之后是長(zhǎng)期與很少或沒(méi)有響應(yīng)的變化,即穩(wěn)定時(shí)期。最后,常常在失敗之前幾個(gè)小時(shí),普遍認(rèn)為反應(yīng)減少的散度期。 表1：齒輪和齒輪輪規(guī)范 號(hào)碼 參數(shù) 齒輪 小齒輪 1 齒數(shù) 64 26 2 模數(shù) 2 2 3 正常壓力角 200 200 4 軸角 900 900 5 齒頂間隙 0.25mm 0.25mm 6 齒頂高 2mm 2mm 7 全齒高 4.5mm 4.5 8 材料 鋼 鋼 表2：齒輪各種缺陷的細(xì)節(jié) 號(hào)碼 齒輪 故障描述 尺寸/毫米 1 運(yùn)行齒輪 齒輪健康 0.75×0.5×40 2 齒輪1 齒根裂紋 1.5×0.5×40 3 齒輪2 齒根裂紋 2.25×0.5×40 4 齒輪3 齒根裂紋 3.0×0.5×40 表1中提到的五個(gè)齒輪與一個(gè)小齒輪的使用細(xì)節(jié)。一個(gè)是新的輪,被認(rèn)為是無(wú)缺陷。在其他四個(gè)齒輪創(chuàng)建缺陷，并使用電火花控制缺陷的大小。表2中描述了各種缺陷的細(xì)節(jié)及其視圖如圖4所示。裂縫的大小大于1mm在實(shí)際情況中遇到。允許系統(tǒng)的初始運(yùn)行一段時(shí)間后，聲壓級(jí)信號(hào)從安裝在測(cè)試結(jié)構(gòu)前面的麥克風(fēng)收入。 表2記錄裂紋大小(g4),每15分鐘被收錄,總共24段錄音(0--6.0 h測(cè)試持續(xù)時(shí)間)的結(jié)果,直到終止測(cè)試。這種類(lèi)型的測(cè)試是首選是為了有機(jī)會(huì)來(lái)監(jiān)控浴破壞模式,即自然的裂紋擴(kuò)展。損害是保證通過(guò)增加剩余的金屬牙區(qū)足夠的壓力在塑性變形區(qū)域測(cè)試時(shí)間的。監(jiān)測(cè)SPL反應(yīng)揭示了一些微妙的變化和增加反應(yīng)。 7、結(jié)果與討論 在圖5中,健康齒輪速度是每分鐘400轉(zhuǎn),負(fù)載是10 Nm,在時(shí)間域(圖5)頻域(圖5 b)聲壓級(jí)(SPL)以1.0米的位置遠(yuǎn)離變速箱。這表明高水平在200 Hz - 300,400Hz - 500 Hz,600 Hz - 700Hz(圖5 b)的頻率范圍,而其余頻率較低的水平幾乎不變。測(cè)量上的負(fù)載的影響:在400 rpm的速度提出了（圖6）,1/3-octave SPL增加隨著負(fù)載的增加而變小。 （a）時(shí)域聲壓基譜 （b）頻域聲壓基譜 圖5：聲壓級(jí)譜 8、結(jié)論 1 -實(shí)驗(yàn)方法可以用于診斷能力開(kāi)發(fā)的這項(xiàng)工作。此外,明顯的周期性脈沖引起的裂縫牙齒出現(xiàn)在時(shí)域和頻域，平均在1.3倍頻率信號(hào)，隨著裂縫水平的增加,這些提取特征的重要的診斷信息中牙齒裂縫損傷。 2-FFT技術(shù)和高階統(tǒng)計(jì)量的RMS反映聲壓級(jí)(SPL) 這可以成為一個(gè)有效的方法來(lái)進(jìn)行預(yù)測(cè)性維護(hù)變速箱。因此經(jīng)濟(jì)而又有很好的發(fā)展前景。 3 -識(shí)別變速箱噪聲的SPL。當(dāng)應(yīng)用于齒輪箱,可準(zhǔn)確反應(yīng)齒輪的狀態(tài)。甚至從齒輪測(cè)試中得到真實(shí)的數(shù)據(jù)。結(jié)果看起來(lái)有前途。此外,提出了噪聲的聲壓級(jí)別(SPL)簽名的方法在其他測(cè)試平臺(tái)進(jìn)行測(cè)試。RMS平均值分析可能是一個(gè)良好的故障早期檢測(cè)和表征指標(biāo)。 4 -為了研究人工誘導(dǎo)裂縫損害變速箱的發(fā)展，幾個(gè)小時(shí)或幾天使用噪聲進(jìn)行了測(cè)試和記錄了SPL監(jiān)控,得到的均方根平均計(jì)算。在錄音中,錄音RMS值的轉(zhuǎn)換時(shí)間突出顯示反映出變速箱關(guān)鍵操作的變化。 16 附件：（外文資料原文） Vehicle gearbox fault diagnosis using noise measurements Sameh M. Metwalley, Nabil Hammad, Shawki A. Abouel-Seoud Faculty of Engineering, Helwan University, Cairo, Egypt. Abstract Noise measurement is one of many technologies for health monitoring and diagnosis of rotating machines such as gearboxes. Although significant research has been undertaken in understanding the potential of noise measurement in monitoring gearboxes this has been solely applied on any types of gears (spur, helical, ..etc.). The condition monitoring of a lab-scale, single stage, gearbox, represents the vehicle real gearbox, using non-destructive inspection methodology and the processing of the acquired waveform with advanced signal processing techniques is the aim of the present work. Acoustic emission was utilized for this purpose. The experimental setup and the instrumentation are present in detail. Emphasis is given on the signal processing of the acquired noise measurement signal in order to extract conventional as well as novel parameters potential diagnostic value from the monitoring waveform. The evolution of selected parameters/features versus test time is provided, evaluated and the parameters with most interesting diagnostic behavior are highlighted. The present work also reports the results concluded by long term (~ 6.0 h) experiments to a defected gear system, with a transverse cuts ranged from 0.75 mm to 3.0 mm to simulate the tooth crack. Different parameters, related by the analysis of the recording signals coming from acoustic emission are presented and their diagnostic value is discussed for the development of a condition monitoring system. Copyright ? 2011 International Energy and Environment Foundation - All rights reserved. Keywords: Diagnostic, Geared system, Sound pressure level, Stationary signal, Faulty gear, Measuring devices, Condition of gear, Monitoring, Maintenance action. 1. Introduction Acoustic emission is defined as the range of phenomena that results in the generation of structure-borne and fluid-borne (liquid, gas) propagating waves due to the rapid release of energy from localised sources within and/or on the surface of a material. The application of the acoustic emission technology in research and industry is well-documented. In relation to gearboxes, a few investigators have assessed the application of acoustic emission technology for diagnostic and prognostic purposes. Others applied acoustic emission in detecting bending fatigue on spur gears and noted that acoustic emission is more sensitive to crack propagation than vibration and stiffness measurements. Again, AE was found to be more sensitive to the scale of surface damage than vibration analysis. 2. Stationary signal data analysis There are numerous signal processing techniques in the literature for fault diagnostics of mechanical systems. Case-dependent knowledge and investigation are required to select appropriate signal processing tools among a number of possibilities. The most common waveform data in condition monitoring are vibration signals and acoustic emissions. Other waveform data are ultrasonic signals, motor current, partial discharge, etc. In the literature, there are two main categories of stationary waveform data analysis; time-domain analysis and frequency-domain analysis. 3. Time-domain analysis Time-domain analysis is directly based on the time waveform itself. Traditional time-domain analysis calculates characteristic features from time waveform signals as descriptive statistics such as mean, peak, peak-to-peak interval, standard deviation, crest factor and high order statistics (root mean square, skewness, kurtosis, etc.). These features are usually called time-domain features. A popular time-domain analysis approach is Time Synchronous Average (TSA). The idea of TSA is to use the ensemble average of the raw signal over a number of evolutions in an attempt to remove or reduce noise and effects from other sources to enhance the signal components of interest. More advanced approaches of time-domain analysis apply time series models to waveform data. The main idea of time series modelling is to fit the waveform data to a parametric time model and extract features based on this parametric model. The popular models used in the literature are the Auto Regressive (AR) model and the Auto Regressive Moving Average (ARMA) model. In this paper, only high order statistic of root mean square (RMS) is used. This feature is usually called time-domain features. RMS is a kind of average of signal, for discrete signals, the RMS value is defined as: 4. Frequency-domain analysis Frequency-domain analysis is based on the transformed signal in frequency domain. The advantage of frequency–domain analysis over time-domain analysis is its ability to easily identify and isolate certain frequency components of interest. The most widely used conventional analysis is the spectrum analysis by mean of fast Fourier transform (FFT). The main idea of spectrum analysis is to either look at the whole spectrum or look closely at certain frequency components of interest and thus extract features from the signal . 5. Constant percentage bandwidth (CPB) The basic choice to be made is between constant absolute bandwidth and constant proportional (percentage) bandwidth where the absolute bandwidth is a fixed percentage of the tuned centre frequency. Constant percentage bandwidth gives uniform resolution on a linear frequency scale, and this for example, gives equal resolution and separation of harmonically related components and this will facilitate detection of a harmonic pattern. However, the linear frequency scale automatically gives a restriction of the useful frequency range to (at the most) two decades. It is worth paying particular attention to two special classes of constant percentage bandwidth filter, viz. octave and third octave filters since these are widely used, in particular for acoustic measurements. The former have a bandwidth such that the upper limiting frequency of the pass band is always twice the lower limited frequency, resulting in the band width of 70.0%. 6. Measuring system and test procedure Figure 1 shows the experimental setup used for the gearbox testing. The gearbox consists of two helical gears with a module of 2 mm, pressure angle 20°, which have 64 and 26 teeth with 40 mm face width. The axes of the gears are supported by two ball bearings each. The entire system is settled in an oil basin in order to ensure proper lubrication. The gearbox is powered by an electric motor and consumes its power on a hydraulic disc brake, while the speed is measured by photo electric probe. Bruel & Kjaer (B&K) portable and multi-channel PULSE type 3560-B-X05 (Figure 2) with condenser 1/2- microphone and preamplifier type 4189A-021 was positioned in the center of gearbox front casing away from the casing and the ground by 1.0 m and 0.50 m respectively [13]. The B&K PULSE labshop is the measurement software type 7700 is used to analyse the results (Figure 3). In terms of various parameters evolution during the test – from a representative test on a gear system with a cut of root thickness to simulate the tooth crack (Figure 4) will be presented and detailed in this study. Many tests were conducted on the same configuration yield similar parameters behaviour. Small cracks were made artificially with wire electrical discharge machining at the root of gear of one tooth to create a stress concentration which eventually led to a propagating crack. The crack depths are ranged from 0.75 mm to 3.0 mm with thickness of almost 0.5 mm. Recordings every 15 min were acquired and a total of 24 recordings (~ 6.0 h of test duration) were resulted until the termination of the test. This type of test was preferred in order to have the opportunity to monitor bath damage modes, i.e., the natural crack propagation. Damage is assured by increasing the test period to the point of where the remaining metal in the tooth area has enough stress to be in the plastic deformation region. Careful monitoring of the SPL responses reveals some subtle and increasing changes in responses. When the gear tooth is brought under load, all the response are seen declining slightly over initial few hours, or 'break-in period'. Break-in period is followed by a long period with little or no change in the responses, 'or stable period'. Finally, often several hours prior to failure, one generally sees the responses decrease during the 'divergence period'. Five gear wheels with one pinion whose details mentioned in Table 1 have been used. One was a new wheel and was assumed to be free from defects (go). In the other four gear wheels, defects were created using EDM in order to keep the size of the defect under control. The details of the various defects are depicted in Table 2 and its view is shown in Figure 4. The size of cracks is a little bigger than one can encounter in the practical situation. The sound pressure level signal from the microphone mounted on front of the test structure was taken, after allowing initial running of the system for sometime. At crack size (g4), Table 2, recordings every 15 min were acquired and a total of 24 recordings (~ 6.0 h of test duration) were resulted until the termination of the test. This type of test was preferred in order to have the opportunity to monitor bath damage modes, i.e., the natural crack propagation. Damage is assured by increasing the test period to the point of where the remaining metal in the tooth area has enough stress to be in the plastic deformation region. Careful monitoring of the SPL responses reveals some subtle and increasing changes in responses. 7. Results and discussion In Figure 5, where the speed is 400 rpm, and load is 10 Nm for healthy gear, the sound pressure level (SPL) measured at a location of 1.0 m away from the gearbox face in time domain (Figure 5a) and in frequency domain (Figure 5b). This indicates high levels in the frequency ranges of 200 Hz-300 Hz, 400 Hz-500 Hz and 600Hz-700 Hz (Figure 5b), while the levels of the remaining frequency are lower and almost constant. The influence of the load on the measured SPLs at speed of 400 rpm is presented in Figure 6, where the 1/3-octave SPL is increased with the increase of the load dispite some small discrepancies exsited in the 1/3-octaves up to 63 Hz (Figure 6b). This may be attributed to the influnce of gear meshing frequencies, rotating shafts frequencies and structure rigidity resonance frequencies. 8. Conclusion 1- The experimental methodology capability developed in this work could be utilized for diagnostic regime. Furthermore, the obvious periodical impulses caused by the cracked tooth appear in time history, frequency domain and in 1.3-octave band averages signals as the crack level increases, these carry diagnostic information which is important for extracting features of tooth crack damage. 2- The FFT technique and the high order statistic of RMS reflect in the Sound pressure level (SPL) responses of the gearbox. This can be an effective way to carry out the predictive maintenance regime and consequently to save money and look promising. 3- The identification of gearbox noise in terms of SPL is introduced. When applied to the gearbox, the method resulted in an accurate account of the state of the gear, even, when applied to real data taken from the gear test. The results look promising. Moreover, the proposed noise in terms of sound pressure level (SPL) signature methodology has to be tested on the other test rig also. RMS average value analysis could be a good indicator for early detection and characterization of faults. 4- In order to study the development of damage in artificially induced cracks in the gearbox, multi-hour tests were conducted and recordings were acquired using noise in terms of SPL monitoring, where the RMS average was calculated. In the recordings, the transitions in the RMS values with the recording time were highlighted suggesting critical changes in the operation of the gearbox. References [1] Singh A, Houser DR. and Vijayakar S. "Detecting gear tooth breakage using acoustic emission: a feasibility and sensor placement study" J Mech Design Trans. ASME 1999;121(4):587–93, 1999. [2] Miyachika K., Zheng Y. and Tsubokura K. "Acoustic Emission of bending fatigue process of supercarburized spur gear teeth" Progress in Acoustic Emission XI. Anonymous. The Japanese Society for NDI; 2002. pp. 304 310, 2002. [3] Singh, A., Houser, D.R. and Vijayakar, S. "Detecting gear tooth breakage using acoustic emission: a feasibility and sensor placement study" Journal of Mechanical Design 21(1999) pp. 587–593,1999. [4] Tandon N. and Mata S. "Detection of defects in gears by acoustic emission" J. Acoustic. Emission 1999;17(1–2):23–7.1999. [5] Kramberger, J., Sraml, M., Glodez, S. Flasker, J. and Potrc, I."Computational model for the analysis of bending fatigue in gears", Computers and structures 82 (23-26), pp 2261-2269, 2004. [6] Loutas, T. H., Sotiriades, G.,Kalaitzoglou, I. and KOstopoulos, V."Condition monitoring of a single-stage gearbox with artificially induced gear cracks utilizing on-line vibration and acoustic emission measurements" Applied Acoustics 70, pp. 1148-1159, 2009. [7] Tan,CK., Irving, P. and Mba, D. "A comparative experimental study on the diagnostic and prognostic capabilities of acoustic emission, vibration and spectrometric oil analysis for spur gears" Mechanical System signal Process, 21(1), pp. 208-233, 2007. [8] Toutountzakis, T., Tan, C. K. and Mba, D. "Application of acoustic emission to seeded gear fault detection" NDT&E Int. 2004;37, pp. 1-10, 2004. [9] Tan, C. K. and Mba, D. "Identification of the acoustic emission source during a comparative study on diagnosis of a spur gearbox" Tribology Int. 2005;38, pp. 469-480, 2005. [10] Eftekharnejad, B. and Mba, D. "Seeded fault detection on helical gears with acoustic. Emission " Applied Acostic 70, pp. 547-555, 2009. [11] Abouel-seoud, S. A., Hammad, N., Abd-elhalim, N., Mohamed, E. and Abdel-hady, M. "Vehicle Gearbox Condition Monitoring Using Vibration Signatural Analysis" SAE Paper No. 2008-01-1654, 2008. [12] Rebbechi, B., Howard, C. and Hasen, C."Active control of gearbox vibration" ACTIVE 99, Fort Lauderdale, Florda USA, December 02-04, 1999. [13] Mille, R.K. and McIntire, P. "Acoustic Emission Testing, vol. 5, second ed" Non- destructive Testing Handbook, American Society for Non-destructive Testing, 1987, pp. 275–310,1987.