1、专业英语翻译 一 stress and strain（应力与应变） 1the fundamental concepts 基本概念 cross section 横截面 the internal stresses produced in the bar 杆的内应力 continuous distribution of hydrostatic pressure 流体静压力 the tensile load 拉伸载荷 a uniform dis tribution over the cross section 在横截 面均匀分布 arbitrary cross-sectional shape 任意截面
2、形状 tensile stresses 拉应力 compressive stresses 压应力 a normal stress 正应力 through the centroid of the cross sectional area 通过横截面形心 the uniform stress condition 压力均匀分布 the stress distribution at the ends of the bar 杆末端应力 分布 high localized stresses 高度应力集中 an axially loaded bar 轴向载荷杆件 a tensile strain 拉应变 a
3、n elongation or stretching of the material 材料拉伸 a compressive strain 压应变 the ratio of two lengths 两个长度的比值 purely statical and geometrical considerations 从纯静态以及几何角度考虑 1.That branch of scientific analysis which motions, times and forces is called mechanics and is made up of two parts, statics and dyna
4、mics. 研究位移、 时间和力运动乘力是科学分析法的一个分支， 被称作力学， 力学由两大部分组成， 静力学和动力学。 2.For example, if the force operating on a sleeve bearing becomes too high, it will squeeze out the oil film and cause metal-to-metal contact, overheating and rapid failure of the bearing. 例如：如果止推轴承上的作用力过大的话，会挤出油膜，引起金属和金属之间的相互接触， 轴承将过热而迅速失效
5、。 3.Our intuitive concept of force includes such ideas as place of application, direction, and magnitude, and these are called the characteristics of a force. 力的直观概念包括力的作用点、大小、方向，这些被称为力的三要素。 4.All bodies are either elastic or plastic and will be deformed if acted upon by forces. When the deformation
6、 of such bodies is small, they are frequently assumed to be rigid, i.e., incapable of deformation, in order to simplify the analysis. 所有的物体既可以是弹性的也可以是塑性的， 如果受到力的作用就产生变形。 当变形很小的 时候它们被假设成刚体，也就是不产生变形。 5.The rigid-body assumption cannot be used in internal stresses and strains due to the applied forces
7、to be analyzed. Thus we consider the body to be capable of deforming. 刚体假设不能应用于内应力和内应变的分析，所以在实际力的分析时，要考虑物体的形变。 6.If all the forces acting on a particle are balanced, the particle will either remain at rest or will continue to move in a straight line at a uniform velocity. 如果作用在质点上所有的力是平衡的，质点将会保持静止或做
8、做匀速直线运动。 2 1) the main manifestations of capacity 主要的表现能力 2) the maximum unit load （ stress） 最大单位载荷（应力） 3） stress-strain diagram 应力 应变图 4） the simple tensile test 简单的拉伸试验 5） the percentage elongation at rupture 断裂伸长率 6） the ends of tensile specimens 拉伸试样的两端 7） permanent deformation 永久变形 8） the resul
9、ting load-displacement curve 由此产生的载荷位移曲线 9） a substantial yielding of the material 大量产生的物质 10） yield point 屈服点 11) the transition from elastic to plastic behavior 从弹性到塑性的 过度 12） material property table 材料属性表 13） plastic deformation 塑性变形 14） a specified standard length of the specimen 指定的标准式样长度 15） a
10、t the moment of rupture 此刻的破裂 16） short cylindrical specimens 短圆柱标本 17） ductile materials 韧性材料 18）high stress concentration 高应力集中 19） ultimate tensile strength 极限抗拉强度 20） strain hardening zone 应变硬化区 1)A tensile test consists of slowly pulling a sample of material with a tensile load until it breaks.
11、 The ends of tensile specimens are usually enlarged to pr ovide extra area for gripping and to avoid having the sample break where it is being gripped. 拉伸试验包括慢慢加载拉伸载荷直到断裂， 拉伸试件两端加粗为了提供装夹区域和避免试件 断裂。 2） The usual manner of conducting the test is to deform the specimen at a constant speed .For example,
12、 in the Universal testing machines, the motion between the fixed and moving cross heads can be controlled at a constant speed. 通常进行试验的方法就是使试件以恒定速度发生变形。 例如，在万能拉伸试验机上，固定端和移动的十字滑块 之间的变形是以恒定速度进行的。 3） The load that must be applied to enforce this displacement rate varies as the test proceeds. This load F
13、 may be divided by the cross-sectional area A to obtain the stress in the specimen at any time during the test. 随着实验的进行，用来产生位移的载荷是随位移的变化而变 化。在实验中，载荷 F 除以横截面积 A 可以得到任意时刻点的应力。 4）However actual measurement of L is preferable where This is feasible. Stress and strain based on the initial (undeformed) di
14、mensions, Ai and Li, are called engineering Stress and strain. 然而，在可行的位置的 L 的实际测量是更可取的，基于原始尺寸 Ai 和 Li 的应力和应变称 为工程应力和工程应变。 5)Ductile and brittle materials behave differently in compression test as well. The compression test is conducted on short Cylindrical specimens placed between parallel plates. 塑
15、性和脆性材料在压缩试验中表现的特性是不相同的。 压缩试验是把短圆柱形试件放在两平行平板之间进行的 6） The compression test diagram for these materials retains.The qualitative features of the tension test diagram.The ultimate compressive strength of a brittle of a brittle material is determined in the same way as in tension. 材料压缩试验图保持了拉伸试验图性能上的特征。 脆
16、性材料的最大压缩强度与最大拉伸强度 得到的方法相同。 第三单元 Virtually all machines contain shafts. The most common shape for shafts is circular and the cross section can be either solid or hollow (hollow shafts can result in weight savings). 几乎所有的机器都有轴，最常用的外形是圆形的，横截面是空心的或实心的圆形截面（空心 轴可以减少重量） 。 A shaft must have adequate torsion
17、al strength to transmit torque and not be overstressed. It must also be torsionally still enough so that one mounted component does not deviate excessively from its original angular position relative to a second component mounted on the same shaft. 一个轴必须有足够的扭转强度来传递扭矩而不会破坏， 同样也必须有足够的扭转刚度， 这样 安装轴就不能过度
18、偏离相对于安装在同一轴上第二个零件的原始位置。 Shafts are mounted on bearings and transmit power through such devices as gears, pulleys, cams and clutches. These devices introduce forces which attempt to bend the shaft; hence, the shaft must be rigid enough to prevent overloading of the supporting bearings. 轴安装在轴承上通 过齿轮，滑
19、轮，凸轮和离合器这些装置传递力。这些装置可以产生使轴弯 曲的力，所以轴必修有足够的刚性防止支撑轴承的过载。 In addition, the shaft must be able to sustain a combination of bending and torsion and bending. 另外，轴必须能承载弯扭组合的载荷，因此，这样就必须考虑弯扭组合的等效载荷。 Components such as gears and pulleys are mounted on shafts by means of key. The design of the key and the corre
20、sponding keyway in the shaft must be properly evaluated. 齿轮和滑轮构件是用键的方式连接在轴上的，键和对应的键槽的设计必须进行估算。 Another important aspect of shaft design is the method of directly connecting one shaft to another. This is accomplished by devices such as rigid and flexible couplings. 轴设计的另一个重要方面是直接连接两轴，通过刚性和柔性的联轴器装置来实现
21、。 4 1) herringbone gears 人字形齿轮 2） spiral gears 螺旋齿轮 3） worm gears 蜗轮 4) bevel gears（圆）锥齿轮，伞齿轮 5） hypoid gears 准双曲面齿轮 6）sizes of spur-gear teeth 轮齿尺寸 7) the automotive rearaxle drives 汽车后桥驱动 8) rack-and-pinion drives 齿条和小齿轮驱动 9) diametral pitch 径节 10) pitch circle 节圆 11) the tangency point 切点 12) pre
22、ssure angles 压力角 13) an involute curve 渐开线曲线 14) the radial distant 径向距离 15) at right angles 成直角 16) the average number of teeth in contact 平均啮合齿数 17) the reciprocal of the diametral pitch 径节的导数 18) to change inches to millimeters 将英寸改为毫米 19) a line perpendicular to the centerlines 垂直于中心线的线 20) cent
23、er distance between two meshed gears 两个互相啮合齿轮的中心距离 1)Pressure angles for spur gears are usually 14.5 or 20 degress, although other values can be used. Meshing gears must have the same pressure angles. 译文：虽然直齿圆柱齿轮的压力角可以取很多其他值，但通常大多是在 14.5 至 20 度之间。 互相啮合齿轮的压力角必须相同。 2)The shape of the space between gea
24、r teeth is complex and varies with the number of teeth on the gear as well as tooth module, so most gear manufacturing methods generate the tooth flank instead of forming. 译文：由于齿轮齿数以及齿形的不同，齿轮齿侧间隙的形状也是复杂多样的，所以大多数齿 轮的制造方法是范成发而不是成型法。 3) Worm gears are used where high ratios are desired and where the sh
25、afts are nointersecting and at right angles. 译文：蜗轮蜗杆常用于那些要求高传动比同时两根轴不交叉但成直角的场合。 4) It has the great advantage that the cutting tool is a simple rack with(nearly) straight sided teeth which can easily be ground accurately. 译文： 一个很大的优势在于刀具是在一个简单的齿条 几乎可以直接准确地支起被磨损的轮齿。 5) Modern shapers cutting car gear
26、s can run at 2000 cutting per minute. The shape of the cutter is roughly the same as an involute gear but the tips of the teeth are rounded. 译文：现代牛头刨床削减汽车齿轮可以运行在每分钟 2000。刀具的形状大致与渐开线齿轮 的圆形轮齿相同。 6) Bevel gears are often used when two shafts are at right angles to each other and their centenline extens
27、ions intersect; however,some bevel gears are at angles other than 90 degrees. 译文：锥齿轮常用于两轴互相垂直且它们中心线的延长线相交的场合下。可是，有些锥齿轮 的轴线并非互相垂直。 5 1.plate cams 盘形凸轮 2. cylindrical cams 圆柱凸轮 3. the cam assemblies in automatic record players 录音机上的凸轮组件 4. cam profiles 凸轮轮廓 5. make a full-scale template 制造一个实尺样板 6. in
28、 the course of several revolutions of the cam 在凸轮转几转的过程中 7. a tangential plate template 切向盘形凸轮 8. a translation cam 移动凸轮 9. the groove in the periphery of the cam 凸轮表面上的槽 10. a guided vertical reciprocated follower 纵向做往复运动的从动件 11. a constant-diameter cam 等径凸轮 12. automatic washing machines 自动洗衣机 13.
29、 a face cam 面凸轮 14. the edge of a pivoted follower 摆动从动件的边缘 15. a reciprocating knife-edged follower 一个做往复运动的刃口式从动件 16. miniature snap-action electrical switches 微型速动电开关 17. a pivoted flat-faced follower 一个转动的平面从动件 18. air pilot values 空气试点值 19. the abrupt change in cam profile 凸轮轮廓的突变 20. a Scotch
30、yoke mechanism 苏格兰约克机构 1.The purpose of any cam is to produce a displacement of its follower is ofen used to produce additional displacement in another location. 使用凸轮的目的是使其从动件产生位移，次级从动件常用来在另一位置产生附加位移 2.The relative vertical position of point A with respect to B needs to be raised if the reaction val
31、ue at B is excessive. 如果 B 点的值超量，点 A 相对于 B 的垂直位置就要升高 3.In general, the follower is considered to be the part that comes in contact with the cam profile. However, when a secondary follower is used, the motion of the secondary follower is dicatated by that of the primary follower. 总的来说，从动件是与凸轮轮廓相接触的零件
32、。然而，当用次级从动件时，次级从动件的运 动就需要通过主要从动件来实现 4.The simplest type of follower is the reciprocating type that merely moves up and down (or in and out) with the rotation of the cam; the centerline can be either collinear with the cam centerline or offset from it. 最简单的从动件是随着凸轮的转动而仅作上下（或进出）往复运动的从动件，其中心线可与 凸轮中心线共线
33、，也可与之偏离。 5.Fasteners are devices which permit one part to be joined to a second part and, hence, they are involved in almost all designs. 紧固件是一种可以连接两个 零件的部件，因此他们几乎在所有设计中都被涉及到 。 6.Springs are mechanical members which are designed to give a relatively large amount of elastic deflection under the action of an externally applied load. 弹簧是一种被设计为在外部负载的作用下能发生相对大量弹性变形的机械部件。
