一. 翻译成汉语
1 A tensile strain 抗拉应变
2 Through the centroid of the cross sectional area 通过截面的质心
3 The transition from elastic to plastic behavior 从弹性变形到塑性变形的过渡
4 Ductile materials 延展性材料
5 Shear modulus of elasticity 弹性剪切模量
6 antifriction bearings减摩擦（滚动）轴承
7 herringbone gears 双螺旋齿轮
8 pressure angles 压力角
9 a constant-diameter cam一种定径凸轮
10 a scotch yoke mechanism 一种止转轭机构
11 stainless steel 不锈钢
12 tool and die steels模具钢，工具钢
13 temper brittlement热脆性
14 thermals stress热应力
15 International Organization for standardization 国际标准化组织
16 planning,grinding and reaming 刨，磨，铰
17 the compressibility of air 空气的可压缩性
18 from hydraulic power to mechnical power从液压能（水能）到机械能
19 dead load静载荷
20 surface roughness 表面粗糙度
二. 翻译成汉语
An axially loaded bar undergoes a change in length,becoming longer when in tension and shorter when in compression. The total change in length is denoted by the Greek letter （delta）and is pictured in fig. l-la for a bar in tension .this elongation is the cumulative result of the stretching of the material throughout the length L of the bar. 一轴向承载的杆在长度方面会发生改变，在拉伸的时候变长，压缩的时候变短。 长度的所有变化用拉丁字母（delta）标示，在图 l-la 中表示的是一在拉伸的杆。这个伸长是整个杆在长度L内所有材料被拉长的累积结果
