外文翻译--固体力学中摩擦学综述

1、 2015 届毕业文献翻译题 目 固体力学中摩擦学综述 专业班级 学 号 学生姓名 指导老师 指导老师职称 副教授 学院名称 机电工程学院 完成日期：2015年6月11日 5翻译原文：Review of solid mechanics in tribology John A. Tichy*, Donna M. Meyer The study of solid mechanics is essential to the field of tribology, (friction, lubrication and wear). Tribology is of immense economic im

2、portance. The potential savings, were tribological principles better understood and applied to friction and wear reduction) may be several percent of the gross national product. Solutions to tribology problems often enable current technologies in a broad spectrum of applications from friction contac

3、t in the turbine shrouds of aircraft engines, to bearing contact in motor vehicle gear assemblies, to the sliding contact of magnetic storage disk drives. Conversely, tribology issues, e.g., the coefficient of friction, may impact solid mechanics problems and tangential tractions are essentially fre

4、e parameters in many cases. Active issues of research in tribology where solid mechanics is applied include: friction and wear in dynamic loading of bearings to extend bearing life; models for contact and thermal stresses of sliding surface asperities; design criteria for magnetic recording heads, a

5、nd behavior of human artificial joints to extend service life.Countless other applications exist, requiring the development of essential theories of conforming and non¬conforming surface behavior. Information such as the frictional response of surfaces in relative motion, and modes of stress an

6、d deformation emerges from the fusion of solid mechanics and tribology. Tribology is the science and technology of interacting surfaces in relative motion. The word itself was first used in England the 1960's and comes from the Greek work 'tribos' meaning 'to rub'. The term was c

7、oined as a conscious attempt to combine the historically independent fields of friction, lubrication and wear in an interdisciplinary manner, as well as to attach a scientific sounding name to studies which were, for the most part, at that time, very applied. The attempt seems to have succeeded and

8、the term tribology has found wide acceptance in both science and engineering. The study of fluid film bearings, rolling element bearings, seals, gears, cams, viscous dampers, human joints, and magnetic storage devices are some of the applications in which tribology is currently used. Tribology is of

9、 immense economic importance, which certainly motivates its study. An improvement in the engineering practice of tribology through better understanding of a contact mechanics problem may involve savings in the billions of dollars. The Jost Report Jost (1966)，in which the term tribology was first use

10、d, attributed about £515M/y (about 1% of the British gross national product) of potential savings were tribological principles better understood and applied. Such a huge economic impact was much derided at the time as self-serving exaggeration; however, the economics may have been greatly under

11、stated. The Jost Report primarily focused on energy loss due to friction but overlooked the much large pervasive costs of wear on maintenance, loss due to breakdowns, depreciation of machinery, etc. Such potential savings through tribology are huge, but clearly very difficult to rigorously quantify.

12、 Recent textbooks discuss the economic impact of tribology in their introductions, Rabinowicz (1995), and Hutchings (1992). The history of the subject dates back to the studies of friction by Thermistius in 350 BC who found that the friction for sliding is greater than that for rolling. This finding

13、 led to the understanding in modern terms that the static friction coefficient is greater than the kinetic coefficient of friction. First noted in the 1500，s by da Vinci, re-discovered by Amontons in 1699, verified by Euler in 1750 and Coulomb in 1781: each found that friction is proportional to loa

14、d and independent of the area of sliding surfaces. Thus the coefficient of friction is independent of load, and in the case of dry (unlubricated) sliding, independent of velocity. Dowson (1997) presents an entertaining history of the field. Little fundamental understanding into solid mechanics aspec

15、ts of tribology was gleaned until this century when measurements could be taken of surface roughness, and inferences made as to the real area of contact between surfaces. Even the smoothest surfaces are rough on the atomic scale and contact only occurs at the tips of asperity peaks, Bowden and Tabor

16、 (1967). At first the deformation is elastic in the manner of the Hertz problem between spherical surfaces, see the discussion below. For metal surfaces, eventually the elastic limit is exceeded and plastic deformation occurs. With fully plastic asperity deformation, the real area of contact Ar is t

17、he (global) normal force P divided by the yield hardness H, Ar 二 P/H, and the friction force Q for dry sliding is the real area of contact times the shear strength Y. The asperity junctions are assumed to be joined by adhesion and then ruptured during sliding. Thus the friction coefficient is shear

18、strength divided by hardness, 二 Q/P 二 Y/H. With similarly simplistic reasoning, a dimensionless wear coefficient K can be defined, Archard (1953), which is wear volume divided by real contact area times sliding distance, K 二 Vol/ArS 二 Vol H/PS. If the plastically deformed zone below the asperity is

19、the same order as the real contact area, then K represents a ratio of worn volume to the plastically deformed zone. For adhesive wear, K loosely represents the probability that an asperity adhesive junction leads to a wear particle. Adhesive wear occurs when asperities are in contact accompanied by

20、high local pressures and sometimes the resulting weld can be stronger than the bulk asperity; the cohesive strength of the softer material being less than the interfacial strength. For abrasive wear, where the asperity material is harder than the material surface through which it is ploughing, a sim

21、ple ploughing idealization leads to K 二 tan S/n where S is the cutting angle, Rabinowicz (1995). For adhesive wear K is order 10_4 to 10"3, and for abrasive wear K is order 10_1. In recent times, tribology is often a so-called pacing technology being crucial to a wide range of applications incl

22、uding high temperature engines made of ceramics, machine tools, metal cutting and forming processes, and biotechnology to name a few. Whether counter surfaces are conforming or nonconforming, made of like or unlike materials, lightly or highly loaded, under steady or dynamic loads, the study of soli

23、d mechanics is integral in solving tribological problems. Many of the present day tribology problems, just as during its early beginnings, require knowledge of a combination of several areas of science. Researchers in the field come from a wide variety of backgrounds: surface science, chemistry of l

24、ubricants, machine design and behavior, material science, rheology, fluid mechanics and the like. Relatively few of the past and presently well-known people in tribology come from the solid mechanics field. Of the three areas of friction, wear and lubrication, only the latter has been broadly tracta

25、ble to a theoretical foundation until very recently. In 1886，Osborne Reynolds developed his theory of hydrodynamic lubrication and the equation that bears his name. Reynolds' equation is a solution to the governing equations of Newtonian fluid mechanics (Navier Stokes) for a thin confined film i

26、n which a three-dimensional nonlinear equation can be integrated to a two-dimensional linear partial differential equation. Solutions to Reynolds' equation form the basis of design and analysis of fluid film bearings. Probably due to the relatively straightforward nature of Reynolds' equatio

27、n, many researchers have approached tribology from a fluid mechanics perspective. The field of solid mechanics as applied to contacting surfaces began in the same era as lubrication theory with the publication of Heinrich Hertz's classic paper 'On the Contact of Elastic Solids' (Hertz, 1

28、882). As pointed out by K.L. Johnson in the preface to his text Contact Mechanics (Johnson, 1987), Hertz' theory was confined to the case of frictionless surfaces and perfectly elastic solids. Removal of the former restriction has led to more realistic consideration of the sliding and rolling co

29、ntacts of machine elements. Much early work in this direction is due to R.D. Mindlin (1949). Development of theories of plasticity and viscoelasticity has allowed application of solid mechanics to a wider range of materials and conditions. However, by contrast with lubrication, no single governing e

30、quation or set of equations could be said to adequately define the solid mechanics of friction and wear problems. Most applications of solid mechanics to tribology are concerned with non-conformal surfaces, which touch first at a point or along a line. Even under finite load, the region affected by

31、the contact is much smaller than the dimensions of the bodies themselves. The contact zone can generally be regarded as a region of stress concentration within the larger body. Strictly speaking, by most conventions, these types of problems comprise the field of contact mechanics. Most of this paper

32、 concerns contact mechanics in the sense just described, but we will use the term to mean 'solid mechanics aspects of tribology. Most of the classical problems of the contact mechanics field have been attacked by building up stress distributions as an integral superposition of point force or lin

33、e force solutions, i.e., the Green's function convolution integral approach. This is the primary approach of Johnson's text, Contact Mechanics (Johnson, 1987), which very adequately reflects the state of the field as of a decade ago. An earlier book Surface Mechanics by F.F. Ling (1973) seem

34、s to have been the first to have specifically addressed solid mechanics aspects of surface and interface phenomena. A wider range of more formal and sophisticated mathematical techniques is explored in the book Contact Problems in the Mathematical Theory of Elasticity by Gladwell (1980). The purpose

35、 of many tribological studies is to predict friction and wear. Global friction and wear are due to a summation of the effect of many asperity interactions, each of which may be idealized as a micro-contact mechanics problem. Much recent solid mechanics-based tribological research has to do with mode

36、ls for rough surface contact, one of the earliest being due to Greenwood and Williamson (1966). They assume that for nominally flat surfaces the summit height distribution is Gaussian with height variance a, and each summit can be replaced with a parabola of a specified radius of curvature R. From t

37、his model one can compute load P and real contact area Ar as a function of h/a, where h is the mean surface separation. In addition a quantity known as the plasticity index = a/R(Ef/H) may be computed which determines the onset of plastic deformation of the asperities. There are numerous roughness m

38、odels along this line, and many studies that make use of such models. Although the three aspects of tribology, those of friction, lubrication and wear, in most cases are interrelated, in the context of solid mechanics the areas of attention are primarily those of friction and wear. The results of mo

39、st solid mechanics analyses are stresses and displacements and the relation of these quantities to the global variables of tribological interest, e.g., friction and wear, may not be clear. Experimentation remains the primary mode for determining such quantities as rates of wear and coefficients of f

40、riction. Material deformations and associated stresses play important, but largely uncertain, roles in determining the quantities of friction and wear. However, until such time that a means to mathematically model friction coefficients or wear rates from first principles exists, the experimental app

41、roaches will trump mathematical analysis in the study of tribological processes. Although the term tribology is new, it is an ancient field with roots in antiquity. With every new mechanical technology a new set of tribological issues seems to arise, the friction and wear of small-scale devices like

42、 MEMS being a good example. Furthermore, mundane issues such as improvements in reliability, vibration control, and condition monitoring, require that strides continue to be made on the tribology of traditional machinery. The contributions made by solid mechanics to the field of tribology have broug

43、ht advancements and improvements in many of these old and new areas. The impact of the combined aspects of tribology reaches into many areas of engineering and science, resulting in achievements and new developments of theoretical understanding and practical benefit. Looking to the next century, inv

44、estigations of a tribological nature will continue to be necessary, as the mechanisms of machinery and mechanical systems become more complex.固体力学中摩擦学综述 固体力学研究在摩擦学领域是必要的（摩擦系数，润滑和磨损）摩擦学有很大的经济效应。对摩擦学理论更好的理解和应用带来的潜在节省也许能高达过面试存在着的几个百分点。摩擦学问题的解决往往能加强现有技术在广泛领域中的应用，从航天器涡轮机壳的摩擦接触到摩托车辆齿轮装配的轴承接触，到磁性存储驱动的滑动接触。

45、相反的，摩擦系数也会影响固体力学和切线向心力是自变量的案例。包含有固体力学的摩擦学活跃的研究课题有：动载轴承的摩擦力和磨损和延长轴承寿命；接触模型和凹凸体滑动表面的热应力；磁性记入头的设计标准，和人造关节的表现和延长服务寿命。另外还存在无数的应用，需要发展必要的结构和非结构表面表现的理论和信息，例如相对运动的摩擦反馈，节点压力和固体力学和摩擦学相结合的形变能量。 摩擦学是相对运动的表面间的科学技术。这个单词本身在20世纪60年代在英格兰被使用，它来源于希腊单词“tribos”意为“去碰擦”。这个短语承载着试图以跨学科的方式去连接历史上的独立领域，摩擦、润滑和磨损的意识，也附带有科学上的名义图研

46、究在那时对于大部分来说是非常实用的。这种尝试似乎已经成功了，并且这个词摩擦学在科学和工程界被广泛接受。液膜轴承、滚动轴承、密封、齿轮、凸轮、粘滞阻尼、人造关节和磁性存储设备是摩擦学被使用中的一部分应用。 摩擦学研究的经济价值推动了对其的研究。通过更好的理解接触力学的问题产生的摩擦学在工程实践上的提高也许能带来数十亿美元的节省。约斯特报告，在其上摩擦学第一次被使用，对摩擦学定理更好的理解和应用将带来每年5.15亿英镑的潜在节省（相当于英国1%国民生产总值）如此大的经济影响当时被嘲笑为利己的自大，然而它的经济价值也许被很大的低估了。约斯特报告起初关注于摩擦导致的能源损失，而忽视了更大的多的无孔不入

47、的对磨损的维护费用以及机器的故障和折旧带来的损失。摩擦学带来的潜在节省如此巨大，但却非常难以准确的量化它。最新的教科书在其介绍部分讨论了摩擦学的经济影响。这门学科的历史可以追溯到公元前350年Thermistius对于摩擦的研究，他发现滑动摩擦比滚动摩擦大。这项发现引导出了对其的现代理解，静摩擦因数比动摩擦因数大。这在16世纪初最先被达芬奇发现，在1699年被阿蒙东再次发现，被欧拉和库伦先后于1750年和1781年确认。他们发现摩擦力和载荷成比例，与滑动表面的面积不相关。此外，摩擦因数独立于载荷，在干的（非润滑）表面，与速度无关。道松发表了这个领域的趣味历史。 对摩擦学的固体力学部分的一点基本

48、理解直到本世纪被发现，当表面粗糙度能被测量和成功的做出真实领域的表面接触的推论。即使最光滑的表面在原子层面也是光滑的，接触仅发生在凹凸体的尖峰上。第一阶段的变形是弹性的在球面间形成赫茨问题，请看下面的讨论。对于金属表面，最终弹性变形被突破，产生塑性变形。随着全免塑性变形，真实接触面积Ar是正压力除以硬度，Ar 二 P/H，干表面上的摩擦力是接触真实接触面积乘以剪切强度。假设凹凸体接头用粘合剂连接滑动中断裂。此外，摩擦因数是剪切强度除以硬度 二 Q/P 二 Y/H. 随着相似的简化原因，定义一个无量纲的磨损系数，等于磨损量除以真实接触面积乘以滑移距离K 二 Vol/ArS 二 Vol H/PS。

49、如果凹凸体下的塑性变形区和真实接触面积相同，代表磨损量对于塑性变形区的比率。对于粘着磨损，代表一个凹凸体附着节点产生磨损颗粒的概率。当凹凸体接触并伴随高压力会导致附着磨损，有时产生的焊缝会比凹凸体本体更强。更软的材料的粘性强度不如其界面强度。对于附着磨损，凹凸体的材料比犁过的材料表面更坚硬，一个简单的理想结果K 二 tan S/n，是切割角度。对于粘着磨损的范围是10_4 到10对于砂磨损，为10_1 最近，摩擦学成为广泛的应用领域的关键技术，包括陶瓷高温引擎，机械工具，金属切割和成型技术和生物技术等等。无论对偶面是协调或非协调，相似或非相似材料，轻载或重载，定载或动载，固体力学的研究和解决摩擦学问题是一个整体。 许多目前的摩擦学问题，仍然处于早期阶段，要求多方面科学领域知识结