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1、 畢業(yè)設(shè)計（論文）外文資料翻譯 學(xué)院： 機械工程學(xué)院 專業(yè)： 機械設(shè)計制造及其自動化 班級： 機113班 姓名： 學(xué)號： 2011307310 外文出處： Availabie online at www.sciencedirect Ultransonics 42(2004) 169-172 附 件：1、外文原文；2、外文資料翻譯譯文。指導(dǎo)教師評語：簽字： 年 月 日附件1：Friction generated ultrasound from geotechnical materialsAbstractDrilling is a process involved with product man

2、ufacturing and for civil engineers, site preparation. The usual requirement is for efficient material removal. In this study, the friction pair interaction generated by a drilling process provides ultrasound information related to parameters for the geotechnical material being drilled, where the dri

3、ll bit has non-degrading ultrasonic characteristics and no essential requirement for material removal. This study has considered monitoring the ultrasonic signal generated by drilling process, with a view to characterising the parameters of the geotechnical material being drilled and provides a nove

4、l method to identify or characterise ground structures. Drilling of geotechnical material systems, typically involve the interaction of a rotating probe and a granular composite medium. The applied load and angular velocity are measured to determine their relevance to the ultrasonic signal. Samples

5、of granular materials have been graded into controlled grain size ranges. Attention has been focused on determining the effects on the ultrasound signal of grain size, bulk density and the water content of the granular material. A comparison between the various granular samples of the different grai

6、n sizes, density, water content and the associated ultrasonic signal has been done. The effect of each variable, and existing theory for these effects is commented upon. The broad aim of this research is to evaluate ultrasonic monitoring of drilling and assess its potential for real-time geotechnica

7、l ground condition monitoring applications and offer it as an alternative to existing methods. _ 2004 Published by Elsevier B.V.1. Introduction The ultrasound generated from a solidsolid friction pair has been the main focus of research concerning friction-generated ultrasound, mainly associated wit

8、h rotating and reciprocating machines. A frictional process developed during relative movement between contacting materials has an inherent level of wear that eventually would result in failure. Monitoring the ultrasonic signal generated from machinery has become an alternative condition-monitoring

9、tool, as the generated signal contains information related to the microcondition of the friction pair. It is possible to detect when components of a machine are becoming worn and a thus reduce the risk of catastrophic failure leading to production down time. Holroyd and Randall 1 discussed the sensi

10、tivity of using acoustic emission (AE) for detecting changes in lubrication, overloading, wear and review a number of different techniques used to analysethe acoustic signature. Further methodologies for analysing the friction generated acoustic signatures were discussed by Bukkapatnam et al. 2 and

11、provide a novel analysis technique based on chaos theory, wavelets and neural networks. Much of the research concerning condition monitoring focuses on the changes in the signal due to wear, but some research have also focused on the parameters associated with the generated acoustic signal.Work by D

12、iei 3 monitored the acoustic emission generated by tool wear during face milling and proposed a power function relationship between the AERMS voltage and the rate of frictional energy dissipationgiven by AERMS ekgssAaV Tm=2 e1T where k and m are constants that depend on the AE measuring system and t

13、he material properties of the friction pair, g is a function of surface roughness and elastic properties of the friction pair, ss is the shear strength of the interfacial material, Aa is the visible area of contact and V is the sliding velocity. The parameters g and Aa essentially define the real ar

14、ea of contact andtherefore, the AERMS is a function of the real area of contact, the shear strength and the sliding velocity. Results obtained by Dieis work also indicated a linearrelationship between the AERMS and the sliding velocity. Jiaa and Dornfield 4 monitored the AE generated by a pin on dis

15、k experiment, highlighting that the AE is caused by impulsive shock due to asperity collisions and micro-vibrations excited by stickslip phenomena. The research shows that the AERMS increases with load while a linear relationship exists between the relative surface velocity and the AERMS. Sarychev a

16、nd Shchavelin 5 describe the frictional process and the generated acoustic emission associated with it. Two general rules were established relating the rate of counting the acoustic pulses (count rate) to the sliding speed of the friction pair and the applied load. The general rule for the dependenc

17、e of the count rate N_ on the sliding velocity is in the form: N_ A t BvX e2T where A and B are constants and X P1. A similar relationship also applies for the dependence of the load on the count rate, but the exponent X 61. A further relationship was expressed relating the AE activity to the regime

18、 of friction in elastic contact: N_ a k N0:71h0:71A0:71 c r0:90R1:60 a V e3T where N is the normal load, h the generalised elastic modulus, Ac the counter area of contact, r the surface asperity tip radius, Ra is the surface roughness and k is a coefficient of proportionality. Further work by Barano

19、v 6 produced two models relating the frictional parameters of the friction pair to the acoustic parameters; count rate and acoustic energy. The model for the count rate is based on the assumption that the rate of counting acoustic pulses is directly proportional to the number of contact points forme

20、d per unit time. Work by Henrique et al. 7 studied particle collisions down an inclined slope and the number of acoustic events were used to monitor the number of collisions (contacts) generated when a ball was rolled down the slope. The model for the acoustic energy relates the mechanical potential

21、 energy generated during the elastic deformation of a contacting asperity to the amplitude distribution of the acoustic signal. The energy model does not take into consideration the effects of wear and is based on the AE generated due to elastic contact.Current studies in friction-generated acoustic

22、s have shown that the acoustic signals contain information relating to the material parameters of the friction pair. The work in this study uses the acoustic signal as a tool to characterise the material properties of the friction pair. The idea for this study originates from a study by Hill 8 for S

23、cientifics, when it became apparent that monitoring the ultrasound generated by a drilling process process had potential for ground condition monitoring. The overall aim of this work is to develop a method of characterising geotechnical materials using a typical drilling process and monitoring the u

24、ltrasound generated due to the interaction between the drill tip and the geotechnical material.2. Experimental designA simplified drilling arrangement has been constructed where a rotating probe is used to maximise the friction at the probe-tipgranular contact. The probe string is designed, using a

25、suitable coupling device, so that the ultrasonic signal is transmitted from the probe tip to a stationary piezoelectric sensor. The signal is amplified by 60 dB and filtered between 250 and 500 kHz. The captured signal is therefore in the mid-ultrasonic range and relates to the transducer monitoring

26、 frequency used. A schematic diagram of the experimental arrangement can be seen in Fig. 1. The probe rotates, while being submerged in a granular medium of controlled particle size, initial density and water content. The feed rate and angular velocity were set to a constant value and the applied lo

27、ad, count rate and ultrasonic energy were simultaneously monitored. The effects of the particle size, density and water content on two ultrasonic parameters (count rate and energy) have been investigated and the system aims to be a future option for ground condition monitoring.3. ResultsThe effect o

28、f load on the count rate can be seen in Fig. 2a. The signal values on the left of the figure correspond to the probe tip not being in contact with the granular medium. When the probe is pushed into the granular material the load increases. The data highlights a stabilizatio(reduction) in the count r

29、ate and is referred to as the characteristic count rate for a particular friction pair. The stabilisation of the count rate means that no more oscillations are being produced due to an increase in the load and therefore the signal amplitude is only subject to amplitude increase. Different grades of

30、particulate material have been used and the characteristic count rate monitored. The results indicate that a lower characteristic count rate occurs as the average particle size is increased. Eight samples of sand were used and the characteristic count rate is compared with the particle size in Fig.

31、2b. Larger particle sizes produce fewer contacts and therefore the results agree with the assumption stated by Baranov et al. 6 that, the rate of counting is proportional to the number of contacts formed per unit time. The results in Fig. 2c reveal that the water content has little effect on the cha

32、racteristic count rate. Four ranges of grain size have been used and the count rate is plotted against the mass percentage water content. There is a small variation in the count rate but the separation in the signals generated by thedifferent particle sizes still exist. Results have revealed that th

33、e count rate value does not significantly change due to the addition of water and that the count ratesignal is mainly dependent on the number of contacts formed. Therefore, regardless of the water content of the sand it is possible to obtain an approximate evaluation of the average particle size.The

34、 ultrasonic signal energy appears to be sensitive to a number of parameters including the particle size, water content, density and mineralogy. Fig. 3a shows the ultrasonic energy signal plotted against the applied force for two different initial dry densities (compacted and loose). Results indicate

35、 that the energy varies linearly with the applied load and the gradient increases with a reduction in the initial density. The effect of varying the density is more apparent when using smaller grain sizes. A change in the density using smaller particulate material will produce a larger affect on the

36、 number of probe granular contacts generated within the apparent contact area. Lower particulate densities produce fewer contacts and therefore the pressure due to the applied force is increased and may account for an increase in the average energy per oscillation as a function of the applied force.

37、 It is expected that an increase in the particulate size would also produce an increase in the acoustic energy as a result of higher contact pressures. Fig. 3b shows the change in the average energy per oscillation due to the applied force against the average particle diameter. Results indicate that

38、 there is no unique relationship between this ultrasonic energy parameter and the particle size, with a peak occurring at 512 lm.The effect of increasing the water content of the granular sample causes the sand to become acoustically quieter (a significant drop in signal amplitude). Although the san

39、d becomes quieter, the rate of change of the ultrasonic energy due to the applied force is not affected by varying the level of water content in a wet sample but there is a noticeable difference in the gradient when comparing a dry sample with a wet sample.4. ConclusionsResults have shown that when

40、probing into granular materials, using a constant sliding velocity the count rate becomes stable (characteristic count rate). The characteristic count rate is affected by a change in the number probegranular contacts and therefore provides a method for characterising the particle size. The water con

41、tent of a granular sample has little effect on the characteristic count rate and data agrees with the assumption stated by Baranov et al. 6 that the count rate is proportional to the number of contacts formed per unit time. However, the data does not agree with the general rule suggested by Sarychev

42、 and Shchavelin 5, as the characteristic count rate does not depend on the applied force. Results provide positive evidence that monitoring the characteristic count rate has potential as a tool for identifying the layers of different particle size in ground structures regardless of the moisture cont

43、ent.The ultrasonic energy signal is sensitive to a variety of parameters including the load, sliding velocity, particle size, density, water content and mineralogy. Results have indicated that the contact pressure, which is affected by altering the density and particle size, affects the acoustic ene

44、rgy signal. However, a continuous increase in the ultrasonic energy due to larger particle sizes, which was expected, did not occur. It is possible that larger particles produce larger particle-probe contact areas thus reducing the contact pressure at a single contact spot but further work is needed

45、 for this to be established. It is clear that the ultrasonic energy contains information relating to the parameters of the friction pair but further investigation is required to fully understand the contribution of each parameter associated with the generated acoustic signal. References1 T.J. Holroy

46、d, N. Randall, Use of acoustic emission for machine condition monitoring, Condition Monitoring 35 (2) (1993) 7579.2 S.T.S. Bukkapatnam, S.R.T. Kumara, A. Lakhtakia, Analysis of acoustic emission signals in machining, ASME Journal of Manufacturing Science and Engineering (1999) 183207.3 E.N. Diei, Ac

47、oustic emission sensing of tool wear in face milling, Journal of Engineering for Industry 109 (1987) 234240.4 C.L. Jiaa, D.A. Dornfield, Experimental studies of sliding friction and wear via acoustic emission signal analysis, Wear 139 (1990) 403424.5 G.A. Sarychev, V.M. Shchavelin, Acoustic emission

48、 method for research and control of friction pairs, Tribology International 24 (1) (1991) 1116.6 V.M. Baranov, E.M. Kudryavtsev, G.A. Sarychev, Calculation of the parameters of acoustic emission when there is external friction between solids, Russian Journal of Non-Destructive Testing 8 (1995) 56957

49、7.7 C. Henrique, M.A. Aguirre, A. Calvo, I. Ippolito, D. Bideau, Experimental acoustic technique in granular flows, Powder Technology94 (1997) 8589.8 R. Hill, Confidential consultancy Report, Scientifics, 1997.附件2：巖土材料的摩擦聲波摘要 鉆井作業(yè)涉及到設(shè)備生產(chǎn)，對于工程師來說，還包括地址的選擇。鉆井通常要求高效地去除材料。在這項研究中，鉆井過程中摩擦副的相互作用提供了被鉆削巖土材料相

50、關(guān)參數(shù)的超聲信息，在這些信息中鉆頭具有非降解的超聲特性，對于材料去除沒有基本的要求。這項研究認為監(jiān)測鉆井過程中產(chǎn)生的超聲波信號，為表征巖土材料鉆削參數(shù)提供了新的觀點，并提供了一種識別或表征地面結(jié)構(gòu)的新方法。巖土材料系統(tǒng)的鉆削，通常涉及一個旋轉(zhuǎn)探頭和顆粒復(fù)合介質(zhì)的相互作用。測量旋轉(zhuǎn)探頭的載荷和角速度可用來確定它們和超聲信號的相關(guān)性。顆粒材料的樣本已經(jīng)把粒徑控制在一定范圍內(nèi)。精力主要集中在確定晶粒尺寸、堆積密度和顆粒材料的含水量對超聲信號的影響。將不同粒徑、密度、水分含量和相關(guān)超聲波信號的顆粒樣本進行比較，解釋每個變量的影響和有關(guān)這種影響的現(xiàn)有理論。這項研究一般的目的是評估鉆井的超聲監(jiān)測，并估計其

51、在巖土地表實時狀態(tài)監(jiān)測中的應(yīng)用潛力，用它來代替現(xiàn)有的一些方法。1.引言固體固體摩擦副產(chǎn)生的超聲波是摩擦產(chǎn)生超聲波研究的重點，主要涉及旋轉(zhuǎn)和往復(fù)運動的機械。相互接觸的材料相對運動過程中的摩擦產(chǎn)生固有的磨損，最終會導(dǎo)致工作故障。監(jiān)測機械產(chǎn)生的超聲波信號已成為一種不可替代的機器狀態(tài)監(jiān)測方法，因為超聲波信號包含了與摩擦副的微觀環(huán)境相關(guān)的信息。當(dāng)機器零件發(fā)生磨損時，用這種方法來查明故障是可行的，因而降低了因災(zāi)難性故障導(dǎo)致生產(chǎn)停機所帶來的風(fēng)險。Holroyd和 Randall 1 論述了利用聲音輻射技術(shù)（AE）檢測潤滑、超載、磨損變化的靈敏度問題，并查閱了許多其他用于分析聲學(xué)特征的技術(shù)。Bukkapatn

52、am等人 2 論述了用于分析摩擦聲信號更先進的方法，并提出了一種基于混沌理論、小波和神經(jīng)網(wǎng)絡(luò)的新的分析技術(shù)。大多數(shù)有關(guān)狀態(tài)監(jiān)測的研究更關(guān)注由磨損引起的聲信號變化，而一些研究也已經(jīng)注意到與產(chǎn)生聲信號相關(guān)的參數(shù)。Diei 3監(jiān)測了表面磨削過程中刀具磨損所產(chǎn)生的聲音輻射，提出了AERMS電壓和摩擦能量耗散率之間的冪函數(shù)關(guān)系 ekgssAaV Tm=2 e1T 。其中k和m取決于聲音輻射測量系統(tǒng)和摩擦副材料性能常數(shù)；g是摩擦副的表面粗糙度和彈性度的函數(shù)；ss是界面材料的剪切強度；Aa是有效接觸面積，V是滑動速率。參數(shù)g和Aa基本決定了有效接觸面積，因此AERMS是有效接觸面積、抗剪強度和滑動速率的函數(shù)

53、。Diei研究的結(jié)果也表明AERMS和滑動速率線性相關(guān)。Jiaa and Dornfield 4 監(jiān)測了大頭針在磁盤上所產(chǎn)生的聲音輻射，表明聲音輻射是由于微凸體碰撞和粘滑現(xiàn)象所激發(fā)的微振動產(chǎn)生脈沖沖擊引起的。 這項研究表明當(dāng)表面相對速度和AERMS之間存在線性關(guān)系時，AERMS隨負荷增加而增加。Sarychev and Shchavelin 5描述了摩擦過程及其產(chǎn)生的聲音輻射，建立了兩條與摩擦副滑動速度及因加載產(chǎn)生的聲脈沖計數(shù)速率（計數(shù)率）相關(guān)的基本原則。計數(shù)率N_對滑動速率依賴性的基本原則的形式是： N_ A t BvX e2T 。其中，A和B是常數(shù)，X取P1。同樣的關(guān)系也適用于載荷對于計數(shù)

54、率的依賴性，只是指數(shù)X取61。進一步把聲音輻射活躍度與彈性接觸產(chǎn)生摩擦的機理聯(lián)系起來，其關(guān)系表示為：N_ a k N0:71h0:71A0:71 c r0:90R1:60 a V e3T 。其中，N是正常負荷量，h是廣義彈性模量，Ac表示非接觸區(qū)的面積，r為表面粗糙度的尖端半徑，Ra是表面粗糙度，k為比例系數(shù)。Baranov6 做了進一步的研究，給出了兩種模型：把摩擦副的參數(shù)與聲音參數(shù)聯(lián)系起來；把計數(shù)率與聲音能量參數(shù)聯(lián)系起來。計數(shù)率模型是基于聲音脈沖計數(shù)率與單位時間內(nèi)所形成接觸點的數(shù)目成正比的假設(shè)。 Henrique等人 7 研究了粒子沿著斜坡向下碰撞，及用于檢測一個球滾下斜坡時產(chǎn)生碰撞（接觸

55、）次數(shù)的聲音發(fā)生次數(shù)。聲音能量模型把一個接觸的微凸體彈性變形過程中產(chǎn)生的機械勢能與聲信號的振幅分布聯(lián)系起來。這種聲音能量模型沒有考慮磨損的影響，而且是基于彈性接觸產(chǎn)生的聲音輻射。目前摩擦聲學(xué)研究已經(jīng)表明聲音信號包含了與摩擦副材料參數(shù)相關(guān)的信息。這項研究工作用聲信號作為一種表征摩擦副材料特性的工具。當(dāng)監(jiān)測鉆井過程中產(chǎn)生的超聲波對地面狀態(tài)監(jiān)測的作用變得明顯的時候，這種思想在Hill 8 為Scientifics所做的一項研究中產(chǎn)生了。這項工作的總體目標(biāo)是研究一種利用典型鉆井過程并監(jiān)測鉆頭和巖土材料相互作用產(chǎn)生的超聲波來描述巖土材料特性的方法。2. 實驗設(shè)計一個簡單的鉆井裝置具有一個使探針顆粒接觸面

56、積最大化的旋轉(zhuǎn)探頭。使用合適的耦合裝置設(shè)計探頭串，使超聲波信號從探頭傳輸?shù)揭粋€固定的壓電傳感器。該信號被放大了60分貝并過濾掉250和500千赫之間的信號。因此所得到的信號在中超聲波的范圍內(nèi)并與所使用傳感器的監(jiān)測頻率有關(guān)。實驗裝置示意圖如圖1所示。探頭伸入具有一定粒徑、初始密度和含水量的顆粒介質(zhì)中旋轉(zhuǎn)。探頭的進給速度和角速度設(shè)置為一定值，并同時監(jiān)測所施加的載荷、計數(shù)率和超聲波能量。粒徑、密度和含水量對兩種超聲參數(shù)（計數(shù)率和能量）的影響被進行了研究，這種研究的目的是為未來地面狀態(tài)監(jiān)測提供一種選擇。3. 實驗結(jié)果載荷對于計數(shù)率的影響如圖2a所示。位于圖左側(cè)的信號數(shù)值對應(yīng)不與顆粒介質(zhì)接觸的探針。當(dāng)探

57、頭推入顆粒材料時，負載隨之增加。對于計數(shù)率模型，所得數(shù)據(jù)要求穩(wěn)定可靠（原始），并將之稱為一個特定摩擦副的“特征計數(shù)率”。計數(shù)率的穩(wěn)定意味著負載的增加不會產(chǎn)生更多的震蕩，因此信號幅度只受振幅增加的影響。實驗中使用了不同等級的顆粒材料，并且其特征計數(shù)率也已被監(jiān)測。 研究結(jié)果表明，隨著平均粒徑的增大特征計數(shù)率會降低。在圖2b中，對八份沙子樣本進行了特征計數(shù)率與粒徑的比較。粒徑越大，接觸面積就越小。因此實驗結(jié)果印證了Baranov等人 6 提出的計數(shù)率與單位時間內(nèi)接觸次數(shù)成正比的假設(shè)。在圖2c中，實驗結(jié)果表明含水量對特征計數(shù)率影響不大。使用四種不同尺寸的晶粒，畫出計數(shù)率與質(zhì)量含水率的關(guān)系曲線。盡管計數(shù)

58、率發(fā)生很小的變化，但是不同粒徑產(chǎn)生的信號分離仍然存在。實驗結(jié)果表明，增加水含量不會引起計數(shù)率地顯著變化，計數(shù)率信號主要取決于產(chǎn)生接觸的次數(shù)。因此，無論沙子含水量多少，都可以獲得其平均粒度的近似計算。超聲波信號的能量似乎對包括顆粒大小、含水量、密度和礦物質(zhì)含量在內(nèi)的一些參數(shù)很敏感。圖3a顯示出超聲波能量信號與施加在兩份不同初始干密度（松散與密實）樣本上的力的關(guān)系曲線。實驗結(jié)果表明，超聲波信號的能量與施加的荷載線性相關(guān)，相關(guān)線的斜率隨樣本初始密度的降低而增加。當(dāng)使用較小的晶粒尺寸時，密度變化對超聲波信號能量的影響更為顯著。使用粒徑更小的顆粒材料時，密度的變化將對表面接觸區(qū)中探針顆粒接觸次數(shù)產(chǎn)生更大

59、的影響。較低的顆粒密度產(chǎn)生更少的接觸，因而荷載產(chǎn)生的壓力增大，并可能使荷載的函數(shù)平均每振蕩的能量增加。預(yù)計由于較高的接觸壓力顆粒尺寸的增加也會使超聲波能量增加。圖3b顯示了由于對平均粒徑施加力而引起平均每振蕩能量的變化。結(jié)果表明在粒徑達到512 lm時超聲波能量參數(shù)和粒徑之間沒有特殊的關(guān)系。 增加顆粒樣本的含水量導(dǎo)致沙子變得更安靜（聲信號幅值顯著下降）。雖然沙子變得更安靜，在潮濕的沙子樣本中因施力產(chǎn)生的超聲波能量的變化率不受水含量變化的影響，但是當(dāng)把干燥的樣本與潮濕的樣本進行比較時，它們在聲波梯度上仍有明顯的差異。4. 結(jié)論 實驗結(jié)果表明，用一個恒定的滑動速率探查顆粒材料時，計數(shù)率趨于穩(wěn)定（特

60、征計數(shù)率）。特征計數(shù)率受到探針顆粒接觸次數(shù)的影響，從而提供了一種用于表征顆粒粒徑的方法。顆粒樣本的含水量對特征計數(shù)率幾乎無影響。而且實驗所得數(shù)據(jù)印證了Baranov等人 6 所提出的計數(shù)率與單位時間內(nèi)接觸次數(shù)成正比的假設(shè)。然而，實驗所得數(shù)據(jù)不符合Sarychev和shchavelin 5 提出的一般規(guī)律，因為特征計數(shù)率不依賴于所施加的力。實驗結(jié)果提供了有力的證據(jù)來表明監(jiān)測特征計數(shù)率具有實現(xiàn)不依賴水分含量而識別地面結(jié)構(gòu)不同粒度層的潛力。超聲波能量信號對于包括負載、滑動速率、粒徑、密度、含水量和礦物質(zhì)含量在內(nèi)的多種參數(shù)很敏感。實驗結(jié)果表明受密度和粒徑變化影響的接觸壓力會影響聲波能量信號。然而，在意

61、料之中，由于更大的顆粒尺寸而引起超聲波能量持續(xù)地增加不會發(fā)生。較大的顆粒產(chǎn)生較大的粒子-探頭接觸面積從而減小單一接觸點的接觸壓力是可能的，但需進一步研究來支持這種觀點。很明顯，超聲波能量包含了與摩擦副參數(shù)相關(guān)的信息，但是為了完全了解與產(chǎn)生聲音信號相關(guān)的每個參數(shù)的分布，還需要做進一步的研究。參考文獻1 T.J. Holroyd, N. Randall, Use of acoustic emission for machine condition monitoring, Condition Monitoring 35 (2) (1993) 7579.2 S.T.S. Bukkapatnam, S.

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64、chev, Calculation of the parameters of acoustic emission when there is external friction between solids, Russian Journal of Non-Destructive Testing 8 (1995) 569577.7 C. Henrique, M.A. Aguirre, A. Calvo, I. Ippolito, D. Bideau, Experimental acoustic technique in granular flows, Powder Technology94 (1997) 8589.8 R. Hill, Confidential consultancy Report, Scientifics, 1997.