外文翻譯--實(shí)驗(yàn)方法

1、<p>　　畢業(yè)設(shè)計(jì)（論文）譯文</p><p>　　題目名稱(chēng)： 滾筒式清洗機(jī) </p><p>　　院系名稱(chēng)： 機(jī)電學(xué)院 </p><p>　　班 級(jí)： </p><p>　　學(xué) 號(hào)： </p><p>　　學(xué)

2、生姓名： </p><p>　　指導(dǎo)教師： </p><p><b>　　2011 年03月</b></p><p><b>　　實(shí)驗(yàn)方法</b></p><p>　　輻射黑色體理論（Chao et al., 1961）和切削表面理論（

3、Friedman and Lenz, 1970）。隨著敏感的紅外感光膠片的發(fā)展，在一個(gè)可被記錄切削側(cè)面溫度場(chǎng)的工具（Boothroyd, 1961）和電視型紅外線(xiàn)敏感的視頻設(shè)備已被哈里斯等人使用（1980年），以熱傳感和半導(dǎo)體量子吸收的原則為基礎(chǔ)的紅外線(xiàn)傳感器的不斷發(fā)展，使得這些傳感器的第二敏感性大于第一次，其時(shí)間常數(shù)很小太 - 在微秒到毫秒的范圍之內(nèi)。圖5.21顯示了最新使用的第二類(lèi)的例子。有兩個(gè)傳感器以及開(kāi)始投入使用，一個(gè)是在1毫米

4、至5毫米的波長(zhǎng)范圍的敏感型銻化銦，另外一個(gè)是從6毫米至13毫米的敏感型碲鎘汞類(lèi)型，通過(guò)與兩個(gè)不同的探測(cè)器信號(hào)比較可以使用溫度測(cè)量更敏感的方法。大部分金屬切削溫度已進(jìn)行了調(diào)查和了解使得更好地了解這個(gè)過(guò)程。原則上，溫度測(cè)量可能用于條件監(jiān)測(cè)，例如，警告說(shuō)如果是天氣太熱導(dǎo)致切割刀具后刀面磨損，然而，尤其是輻射能尺寸，在生產(chǎn)條件，校準(zhǔn)問(wèn)題以及確保輻射能量途徑從傷口區(qū)到探測(cè)器不被打斷的困難，使得以溫度測(cè)量為目的方法不夠可靠切削的另一種方式是監(jiān)測(cè)聲發(fā)

5、射，這雖然是一個(gè)間接的方法，但研究過(guò)程的狀態(tài)是一個(gè)值</p><p><b>　　5.4 聲發(fā)射</b></p><p>　　材料的活躍形變—例如裂縫的增長(zhǎng)，變形夾雜物，快速塑性剪切，甚至晶界，位錯(cuò)運(yùn)動(dòng)都是伴隨著彈性應(yīng)力波的排放而產(chǎn)生。這就是聲發(fā)射（AE）。排放的發(fā)生在一個(gè)很寬的頻率范圍內(nèi)，但通常是從10萬(wàn)赫到1兆赫。雖然波幅度很小，但是他們可以被檢測(cè)到，通過(guò)強(qiáng)烈的壓

6、電材料如鈦酸鋇或壓電陶瓷傳感器制造從，（Pb（ZrxTi1–x）O3; x = 0.5 to 0.6）。圖5.22顯示了傳感器的結(jié)構(gòu)。聲波傳送到壓力傳感器造成直接的壓力E（△L/L），其中E是傳感器的楊氏模量，L是它的長(zhǎng)度，△L是它的長(zhǎng)度變化。應(yīng)力產(chǎn)生電場(chǎng)</p><p>　　T = g33E(△L/L)（5.7a）</p><p>　　g33是傳感器材料的壓電應(yīng)力系數(shù)。傳感器兩端的電壓是

7、TL，然后</p><p>　　V= g33E△L（5.7b）</p><p>　　g33和E的典型值分別是24.4 × 10-3Vm/ N和58.5GPa，以檢測(cè)電壓高達(dá)0.01毫伏，這是可能的。將這些值代入方程（5.7b）導(dǎo)致了檢測(cè)△L的長(zhǎng)度變化的可以小到7 × 10-15米：對(duì)于一個(gè)L = 10毫米的傳感器來(lái)說(shuō)，即相當(dāng)于擁有7 × 10-13</p

8、><p>　　圖5.22顯示的是聲發(fā)射傳感器的結(jié)構(gòu)</p><p><b>　　實(shí)驗(yàn)理論方法</b></p><p>　　的最小應(yīng)變，使用應(yīng)變傳感要比使用鋼絲應(yīng)變計(jì)更敏感，敏感的最低檢測(cè)應(yīng)變約為10-6。一個(gè)AE傳感器電信號(hào)處理可分為兩個(gè)階段。第一個(gè)是通過(guò)使用一個(gè)低噪聲前置放大器和一個(gè)帶通濾波器（≈100千赫到1兆赫）。由此產(chǎn)生的信號(hào)通常具有的基礎(chǔ)

9、上的復(fù)雜形式，如圖5.23所示，在處理的第二階段，提取信號(hào)的主要特征，例如事件的數(shù)量，電壓超過(guò)某一閾值VL，最大電壓VT，或信號(hào)能量的脈沖頻率使用聲發(fā)射來(lái)進(jìn)行狀態(tài)監(jiān)測(cè)具有許多優(yōu)點(diǎn)。一小部分傳感器，處于策略性部署，能調(diào)查整個(gè)機(jī)械系統(tǒng)。一個(gè)發(fā)射源可以通過(guò)不同次數(shù)的排放以到達(dá)不同的傳感器。它的高靈敏度已經(jīng)被提到。這也是很容易被記錄的;并且聲發(fā)射測(cè)量?jī)x器重量輕而且體積小。然而，它也有一些缺點(diǎn)。這些傳感器必須直接連接到被監(jiān)視系統(tǒng)：這會(huì)導(dǎo)致長(zhǎng)期的可

10、靠性問(wèn)題。在嘈雜的條件下可以使之成為不可能孤立的事件。聲發(fā)射是很容易受被監(jiān)視材料的狀態(tài)的影響，例如熱處理，預(yù)應(yīng)變和溫度。此外，由于聲發(fā)射事件和被監(jiān)視的系統(tǒng)狀態(tài)兩者關(guān)系的特點(diǎn)并不明顯，甚至比熱輻射測(cè)量需要更多的校準(zhǔn)或壓力測(cè)量系統(tǒng)。</p><p>　　在加工過(guò)程中，聲發(fā)射信號(hào)的主要來(lái)源是剪切帶，片工具和工具的工作接觸區(qū)域，切屑的破碎與碰撞，及其切削工具的特征。聲發(fā)射信號(hào)的功率比較大，一般見(jiàn)于范圍100千赫至300千

11、赫。其基本性能的研究和檢測(cè)磨損工具的使用，并且切削已經(jīng)成為大量調(diào)查的主題，例如Iwata和Moriwaki（1977），Kakino（1984），Diei和Dornfeld（1987）。聲發(fā)射的使用潛力可以在圖5.24看出來(lái)。它顯示了一個(gè)后刀面磨損VB和振幅水平之間的關(guān)系</p><p>　　那就是AE信號(hào)會(huì)轉(zhuǎn)化0.45％的普通碳素鋼（Miwa，1981）。較大的側(cè)面磨損，較大的聲發(fā)射信號(hào)，而與具有耐磨變化切削條

12、件的信號(hào)的變化率有關(guān)，例如切割速度。</p><p><b>　　參考文獻(xiàn)</b></p><p>　　Boothroyd, G.（1961）金屬切削溫度的測(cè)定攝影技術(shù)。</p><p>　　英國(guó)J. Appl.物理學(xué). 12，238-242.</p><p>　　Chao, B. T., Li, H. L. 和 Tri

13、gger, K. J.（1961）對(duì)刀腹的表面溫度分布的實(shí)驗(yàn)研究Trans. ASME J. Eng. Ind. 83, 496–503.</p><p>　　Diei，EN和Dornfeld，D. A.（1987）從端面銑削過(guò)程的聲發(fā)射—過(guò)程變量的影響。Trans ASME J. Eng. Ind. 109, 92–99.</p><p>　　Friedman, M. Y. and Le

14、nz, E.（1970）切屑表面溫度場(chǎng)的測(cè)定。</p><p>　　機(jī)械工程研究所19（1），395-398.</p><p><b>　　實(shí)驗(yàn)理論方法</b></p><p>　　Harris, A., Hastings, W. F.和Mathew, P.（1980）切削溫度的試驗(yàn)測(cè)量。</p><p>　　見(jiàn)于：Pr

15、oc. Int. Conf. on Manufacturing Engineering,墨爾本，8月25-27日，第30-35。</p><p>　　Iwata, I. and Moriwaki, T.（1977）對(duì)聲發(fā)射中的應(yīng)用工具傳感進(jìn)程的</p><p>　　磨損。機(jī)械工程研究所26（1），21-26。</p><p>　　Kakino, K.（1984）金屬

16、切削和磨削過(guò)程聲發(fā)射監(jiān)測(cè)3，108-116。</p><p>　　Miwa,Y., Inasaki, I. and Yonetsu, S.（1981）用聲發(fā)射信號(hào)故障檢測(cè)工具的過(guò)程，Trans JSME 47, 1680–1689.</p><p>　　Reichenbach, G. S.（1958）實(shí)驗(yàn)的金屬切削溫度分布測(cè)量。 </p><p>　　Trans A

17、SME 80, 525–540.</p><p>　　Schwerd, F. (1933) Uber die bestimmung des temperaturfeldesbeimspanablauf. Zeitschrift VDI 77,</p><p><b>　　211–216.</b></p><p>　　Shaw, M. C. (1

18、984) 金屬切削原理。牛津：Clarendon出版社。</p><p>　　Trent, E. M. (1991) 金屬切削第三版。牛津：北海海涅曼。</p><p>　　Ueda, T., Sato, M. and Nakayama, K. (1998) 單晶鉆石刀具溫度的轉(zhuǎn)變。 CIRP 47(1), 41–44.</p><p>　　Williams, J

19、. E, Smart, E. F. and Milner, D. (1970)冶金的加工，第一部分. Metallurgia</p><p><b>　　6</b></p><p><b>　　力學(xué)進(jìn)展</b></p><p><b>　　6.1簡(jiǎn)介</b></p><p>　

20、　第2章介紹了最初的機(jī)械，熱及摩擦學(xué)加工過(guò)程的報(bào)告。演示實(shí)驗(yàn)的報(bào)告研究表明，在剪切面角，摩擦角和前角之間沒(méi)有獨(dú)特的的關(guān)系;證據(jù)表明這部分可能受主剪切帶加工硬化;切削速度與高溫之間的關(guān)系和高應(yīng)力條件下使摩擦面的摩擦角條件不足的影響。3至5章集中描述了工件和刀具材料的性能，刀具磨損和故障的本質(zhì)和加工后的實(shí)驗(yàn)方法過(guò)程。這使得針對(duì)描述力學(xué)進(jìn)展的背景下，導(dǎo)致有能力來(lái)預(yù)測(cè)從機(jī)械加工行為和物理性質(zhì)的工作及其工具。</p><p&g

21、t;　　本章安排了除本介紹之外的三個(gè)部分：滑移線(xiàn)場(chǎng)模型，從而使成連續(xù)切屑形成具有很大的啟示，但這最終是令人沮喪的，因?yàn)樗罱K沒(méi)有提供去刪除以上所指非唯一性的辦法;考慮到建模的工作流引入應(yīng)力變化的影響這消除了非唯一性，即使只通過(guò)一個(gè)近似的方式；第一個(gè)實(shí)例，以對(duì)切屑形成的正交模型來(lái)擴(kuò)展更多的一般的三維（非正交）的條件。這是一個(gè)第2章與現(xiàn)代數(shù)值（有限元）制作經(jīng)典材料之間的過(guò)渡章節(jié)第7章。</p><p><b&g

22、t;　　6.2滑線(xiàn)場(chǎng)模擬</b></p><p>　　第2章介紹了兩個(gè)早期的平面的剪切角依賴(lài)摩擦和斜角的理論。根據(jù)Merchant（1945）（方程（2.9））切屑的形成發(fā)生在一個(gè)給定摩擦最低能量的條件下。據(jù)Lee和Shaffer（1951年）（方程（2.10）），剪切面的夾角是由在第二剪切帶相關(guān)的塑性流動(dòng)摩擦角規(guī)則。Lee和Shaffer的貢獻(xiàn)首次是在slipline的切屑形成磁場(chǎng)模型。</p

23、><p>　　6.2.1 滑移線(xiàn)場(chǎng)理論</p><p>　　滑移線(xiàn)場(chǎng)理論適用于平面應(yīng)變（二維）的塑性流動(dòng)。材料的力學(xué)性能被簡(jiǎn)化為剛性，完全塑料。這就是說(shuō)，它的彈性模量被認(rèn)為是不定的（剛性）及其塑性流動(dòng)時(shí)發(fā)生的應(yīng)用是最大剪應(yīng)力達(dá)到某一臨界值，k，它不隨條件，如應(yīng)變，應(yīng)變率和溫度流動(dòng)的變化而變化。對(duì)于這樣一個(gè)在平面上的理想化材料，應(yīng)變塑性狀態(tài)，滑移線(xiàn)場(chǎng)理論發(fā)展的壓力和速度如何可以改變規(guī)則。這些被認(rèn)

24、為是在詳細(xì)附錄1之中。一個(gè)簡(jiǎn)短的部分在這里給出了摘要，足以使該理論應(yīng)用到加工中。</p><p>　　首先：什么是滑移線(xiàn)和滑移線(xiàn)場(chǎng);以及他們有用嗎？一個(gè)平面材料的應(yīng)力應(yīng)變加載的分析結(jié)論是，在任何一點(diǎn)上都有兩個(gè)正交方向，其中剪應(yīng)力方向?yàn)樽畲笾怠４送?，在這些方向直接應(yīng)力是平等的（和平等的靜水壓力）。然而，這些方向可以從一個(gè)點(diǎn)到另一個(gè)點(diǎn)而改變。如果材料是加載塑性，應(yīng)力狀態(tài)完全是所描述的最大剪應(yīng)力常數(shù)K值，以及方向和靜水

25、壓力各不相同的點(diǎn)。 A線(xiàn)，一般彎曲，沿其長(zhǎng)度最大剪應(yīng)力方向都被稱(chēng)為滑移線(xiàn)。一個(gè)滑移線(xiàn)是正交曲線(xiàn)滑移在塑料地帶現(xiàn)有生產(chǎn)線(xiàn)配套?；€(xiàn)場(chǎng)理論是構(gòu)建在特定情況下的滑移線(xiàn)場(chǎng)（例如規(guī)則加工）和計(jì)算領(lǐng)域內(nèi)的靜水壓力的變化之上。</p><p>　　該文章摘自：Metal MachiningTheory and Applications</p><p>　　Thomas Childs</p>

26、<p>　　University of Leeds,UK</p><p>　　Katsuhiro Maekawa</p><p>　　Ibaraki University,Japan</p><p>　　Toshiyuki Obikawa</p><p>　　Tokyo Institute of Technology,Japan&

27、lt;/p><p>　　Yasuo Yamane</p><p>　　Hiroshima University,Japan</p><p>　　http://www.arnoldpublishers.com</p><p>　　Copublished in North,Central and South America by</p>

28、<p>　　John Wiley & Sons Inc.,605 Third Avenue,</p><p>　　New York,NY 10158–0012</p><p>　　Experimental methods</p><p>　　(Chao et al.,1961) and on the chip surface (Friedman

29、and Lenz,1970). With the development of infrared sensitive photographic film,temperature fields on the side face of a chipand tool have been recorded (Boothroyd,1961) and television type infrared sensitive video equipmen

30、t has been used by Harris et al. (1980).</p><p>　　Infrared sensors have continued to develop,based on both heat sensing and semiconductor quantum absorption principles. The sensitivity of the second of these

31、 is greater than the first,and its time constant is quite small too in the range of ms to ms. Figure 5.21 shows a recent example of the use of the second type. Two sensors,anInSb type sensitive in the 1 mm to 5 mm wavele

32、ngth range and a HgCdTetype,sensitive from 6 mm to 13 mm, were used:more sensitive temperature measurements may be made by </p><p>　　Most investigations of temperature in metal cutting have been carried out

33、to understand the process better. In principle,temperature measurement might be used for condition monitoring,for example to warn if tool flank wear is leading to too hot cutting conditions. However,particularly for radi

34、ant energy measurements and in production conditions,calibration issues and the difficulty of ensuring the radiant energy path from the cutting zone to the detector is not interrupted,make temperature measu</p>&l

35、t;p>　　Fig. 5.21 Experimental set-up for measuring the temperature of a chip’s back surface at the cutting point, using a diamond tool and infrared light, after Ueda et al. (1998)</p><p>　　Acoustic emissi

36、on 155</p><p>　　anotherway,albeit an indirect method,to study the state of the process,and this is considered next.</p><p>　　5.4Acoustic emission</p><p>　　The dynamic deformation of

37、 materials – for example the growth of cracks,the deformation of inclusions,rapid plastic shear,even grain boundary and dislocation movements is accompanied by the emission of elastic stress waves. This is acoustic emiss

38、ion (AE).Emissions occur over a wide frequency range but typically from 100kHz to 1MHz.Although the waves are of very small amplitude,they can be detected by sensors madefrom strongly piezoelectric materials,such as BaTi

39、O3 or PZT (Pb(ZrxTi1–x)O3; x = 0.5</p><p>　　Figure 5.22 shows the structure of a sensor. An acoustic wave transmitted into thesensor causes a direct stressE(DL/L) where E is the sensor’s Young’s modulus, L i

40、s itlength and DL is its change in length. The stress creates an electric field</p><p>　　T = g33E(DL/L)(5.7a)</p><p>　　where g33 is the sensor material’s piezoelectric stress coefficient. The vo

41、ltage across thesensor,TL,is then</p><p>　　V = g33EDL (5.7b)</p><p>　　Typical values of g33 and E for PZT are 24.4 × 10–3 Vm/N and 58.5GPa. It is possible,withamplification,to detect voltag

42、es as small as 0.01 mV. These values substituted intoequation (5.7b) lead to the possibility of detecting length changes DL as small as 7 × 10–15m:for a sensor with L = 10mm,that is equivalent to a minimum strain of

43、 7 × 10–13. AE</p><p>　　Fig. 5.22 Structure of an AE sensor</p><p>　　156 Experimental methods</p><p>　　Fig. 5.23 An example of an AE signal and signal processingstrain sensing

44、 is much more sensitive than using wire strain gauges,for which the minimum detectable strain is around 10–6.</p><p>　　The electrical signal from an AE sensor is processed in two stages. It is first passedth

45、rough a low noise pre-amplifier and a band-pass filter (≈100kHz to 1MHz). The resulting signal typically has a complicated form,based on events,such as in Figure 5.23. In thesecond stage of processing,the main features o

46、f the signal are extracted,such as thenumber of events,the frequency of pulses with a voltage exceeding some threshold valueVL,the maximum voltage VT,or the signal energy.</p><p>　　The use of acoustic emissi

47、on for condition monitoring has a number of advantages. Asmall number of sensors,strategicallyplaced,can survey the whole of a mechanicalsystem. The source of an emission can be located from the different times the emiss

48、iontakes to reach different sensors. Its high sensitivity has already been mentioned. It is alsoeasy to record; and acoustic emission measuring instruments are lightweight and small.However,it also has some disadvantages

49、. The sensors must be attached dir</p><p>　　In machining,the main sources of AE signals are the primary shear zone,the chip–tooland tool–work contact areas,the breaking and collision of chips,and the chippin

50、g andfracture of the tool. AE signals of large power are generally observed in the range 100kHzto 300kHz. Investigations of their basic properties and uses in detecting tool wear andchipping have been the subject of nume

51、rous investigations,for example Iwata andMoriwaki (1977),Kakino (1984) and Diei and Dornfeld (1987). The potential of</p><p>　　is seen in Figure 5.24. It shows a relation between flank wear VB and the amplit

52、ude level</p><p>　　References 157</p><p>　　Fig. 5.24 Relation between flank wear VB and amplitude of AE signal, after Miwa et al. (1981)of an AE signal in turning a 0.45% plain carbon steel (Miw

53、a,1981). The larger the flankwear,the larger the AE signal,while the rate of change of signal with wear changes withthe cutting conditions,such as cutting speed.</p><p>　　References</p><p>　　Boo

54、throyd,G. (1961) Photographic technique for the determination of metal cutting temperatures.British J. Appl. Phys. 12,238–242.</p><p>　　Chao,B.T.,Li,H.L. and Trigger,K.J. (1961) An experimental investigation

55、 of temperature distribution at tool flank surface. Trans. ASME J. Eng. Ind. 83,496–503.</p><p>　　Diei,E.N. and Dornfeld,D.A. (1987) Acoustic emission from the face milling process – the effectsof process va

56、riables. Trans ASME J. Eng. Ind. 109,92–99.</p><p>　　Friedman,M.Y. and Lenz,E. (1970) Determination of temperature field on upper </p><p>　　chip face. AnnalsCIRP 19(1),395–398.</p><p&

57、gt;　　158 Experimental methods</p><p>　　Harris,A.,Hastings,W.F. and Mathew,P. (1980) The experimental measurement of cutting temperature. In: Proc. Int. Conf. on Manufacturing Engineering,Melbourne,25–27 Aug

58、ust,pp. 30–35.</p><p>　　Iwata,I. and Moriwaki,T. (1977) An application of acoustic emission to in-process sensing of toolwear. Annals CIRP 26(1),21–26.</p><p>　　Kakino,K. (1984) Monitoring of me

59、tal cutting and grinding processes by acoustic emission. J.Acoustic Emission 3,108–116.</p><p>　　Miwa,Y.,Inasaki,I. and Yonetsu,S. (1981) In-process detection of tool failure by acoustic emissionsignal. Tra

60、ns JSME 47,1680–1689.</p><p>　　Reichenbach,G.S. (1958) Experimental measurement of metal cutting temperature distribution.Trans ASME 80,525–540.</p><p>　　Schwerd,F. (1933) Uber die bestimmung de

61、s temperaturfeldesbeimspanablauf. Zeitschrift VDI 77,211–216.</p><p>　　Shaw,M.C. (1984) Metal Cutting Principles. Oxford:Clarendon Press.Trent,E.M. (1991) Metal Cutting,3rd edn. Oxford:Butterworth Heinemann.

62、Ueda,T.,Sato,M. and Nakayama,K. (1998) </p><p>　　The temperature of a single crystal diamond tool inturning. Annals CIRP 47(1),41–44.</p><p>　　Williams,J.E,Smart,E.F. and Milner,D. (1970) The me

63、tallurgy of machining,Part 1. Metallurgia</p><p><b>　　6</b></p><p>　　Advances in mechanics</p><p>　　6.1Introduction</p><p>　　Chapter 2 presented initial mec

64、hanical,thermal and tribological considerations of themachining process. It reported on experimental studies that demonstrate that there is nounique relation between shear plane angle,friction angle and rake angle; on ev

65、idence thatpart of this may be the influence of workhardening in the primary shear zone; on hightemperature generation at high cutting speeds; and on the high stress conditions on the rakeface that make a friction angle

66、an inadequate descriptor of f</p><p>　　This chapter is arranged in three sections in addition to this introduction:an account ofslip-line field modelling,which gives much insight into continuous chip formati

67、on butwhich is ultimately frustrating as it offers no way to remove the non-uniqueness referredto above; an account of the introduction of work flow stressvariation effects intomodelling that removes the non-uniqueness,e

68、ven though only in an approximate manner in thefirst instance; and an extension of modelling from orthogonal chi</p><p>　　6.2Slip-line field modeling</p><p>　　Chapter 2 presented two early theor

69、ies of the dependence of the shear plane angle on thefriction and rake angles. According to Merchant (1945) (equation (2.9)) chip formationoccurs at a minimum energy for a given friction condition. According to Lee and S

70、haffer(1951) (equation (2.10)) the shear plane angle is related to the friction angle by plastic flowrules in the secondary shear zone. Lee and Shaffer’s contribution was the first of the slipline field models of chip fo

71、rmation.</p><p>　　160 Advances in mechanics</p><p>　　6.2.1Slip-line field theory</p><p>　　Slip-line field theory applies to plane strain (two-dimensional) plastic flows. A material’

72、smechanical properties are simplified to rigid,perfectly plastic. That is to say,its elasticmoduli are assumed to be infinite (rigid) and its plastic flow occurs when the applied maximum shear stress reaches some critica

73、l value, k,which does not vary with conditions ofthe flow such as strain,strain-rate or temperature. For such an idealized material,in a planestrain plastic state,slip-line field theory dev</p><p>　　from pla

74、ce to place. These are considered in detail in Appendix 1. A brief and partialsummary is given here,sufficient to enable the application of the theory to machining tobe understood.</p><p>　　First of all:what

75、 are a slip-line and a slip-line field; and how are they useful? The analysis of stress in a plane strain loaded material concludes that at any point there are two orthogonal directions in which the shear stresses are ma

76、ximum. Further,the direct stresses are equal(and equal to the hydrostatic pressure) in those directions. However,those directions can varyfrom point to point. If the material is loaded plastically,the state of stress is

77、completelydescribed by the constant value k</p><p>　　Article from ：Metal MachiningTheory and Applications</p><p>　　Thomas Childs</p><p>　　University of Leeds,UK</p><p>

78、;　　Katsuhiro Maekawa</p><p>　　Ibaraki University,Japan</p><p>　　Toshiyuki Obikawa</p><p>　　Tokyo Institute of Technology,Japan</p><p>　　Yasuo Yamane</p><p>

79、;　　Hiroshima University,Japan</p><p>　　http://www.arnoldpublishers.com</p><p>　　Copublished in North,Central and South America by</p><p>　　John Wiley & Sons Inc.,605 Third Avenu