.LESSON 1tensile stress 拉应力tensile strain 拉应变compressive stress 压应力compressive strain 压应变normal stress 正应变normal strain 正应力cross section 横截面the tensile load 拉伸载荷bristtle materials 脆性材料ductile materials 塑性材料permanent deformation 永久变形allowable stress 许用应力allowable load 许用载荷ultimate stress极限应力concentrated loads 集中载荷distributed loads 分布载荷simple beam 简支梁cantilever beam 悬臂梁beam with an overhang 外伸梁linear elastic range 线性弹性范围factor of safety 安全系数LESSON 2
