专业英语翻译
—一 stressand 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 an 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 dynamics. 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
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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。 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 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 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 做做匀速直线运动。
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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 resulting 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) at 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. The ends of tensile specimens are usually enlarged to pr ovide extra area for gripping and to
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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, 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 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) dimensions, Ai and Li, are called engineering Stress and strain. 然而，在可行的位置的厶
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 性和脆性
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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 torsional 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
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机械制造专业英语--课后答案(部分)
