材料力学双语教学学习资料1 第一章绪论Chapter 1 Introduction§1-1 材料力学的任务The Tasks of Mechanics of Materials1＊. 材料力学: Mechanics of Materials2. 构件: Structural Members3. 变形: Deformation4＊. 强度: Strength5＊. 刚度: Rigidity6＊. 稳定性: Stability§1-2 变形固体的基本假设Fundamental Assumptions of SolidDeformation Bodies1. 连续性假设: Continuity2. 均匀性假设: Homogeneity3. 各向同性假设: Isotropy§1.3 外力及其分类External Forces and Classification1. 分布力: Distributed Force2. 集中力: Point Force3. 静载荷: Static Load4. 动载荷: Dynamic Load§1.4 内力、截面法和应力的概念Concepts of Internal Forces，Method ofSection and Stress1＊. 内力: Internal Force2＊. 截面法: Method of Section3. 截面法的三个步骤：截开，代替，平衡Three steps of method of section: cut off, substitute , and equilibrium.4＊. 应力: Stress5. 平均应力：Average stress6. 应力（全应力）：Whole stress（sum stress）7＊. 正应力: Normal Stress8＊. 剪应力(切应力)：Shearing Stress§1.5 变形与应变Deformation and Strain1．线应变: Strain2．剪应变: Shearing Strain§1.6 杆件变形的基本形式Basic Types of Deformations of Rods1＊. 拉伸或压缩: Tension or Compression2＊. 剪切: Shear3＊. 扭转: Torsion4＊. 弯曲: Bending第二章拉伸、压缩与剪切Chapter 2 Tension，Compression andShear§2.1 轴向拉伸与压缩的概念和实例The Concept and Examples of AxialTension and Compression1. 拉杆: Tensile Rod2. 压杆: Compressive Rod3. 受力特点：外力合力的作用线与杆轴线重合Characteristic of the External Forces: The acting line of the resultant of external forces is coincided with the axis of the rod.4. 变形特点：杆沿轴向伸长或缩短Characteristic of Deformation: Rod will elongate or contract along the axis of the rod.§2.2 轴向拉伸或压缩时横截面上的内力和应力Internal Force and Stress of Axial Tension or Compression on the Cross Section1＊. 横截面: Cross Section2＊. 轴力: Normal Force3＊. 轴力图: Diagram of Normal Force§2.3 直杆轴向拉伸或压缩时斜截面上的应力Stress of Axial Tension or Compressionon the Skew Section1. 斜截面: Skew Section2.ασσα2cos = αστα2s i n 2=§2.4 材料在拉伸时的力学性能Mechanical Properties of Materialswith Tensile Load1. 标准试件: Specimen2. 低碳钢(C ≤0.3%): Low Carbon Steel3. 弹性阶段:Elastic Region4. 屈服阶段:Yielding Stage5. 强化阶段:Hardening Stage6. 颈缩阶段: Necking Stage 7＊.σp ----比例极限: Proportional Limit 8＊.σe ----弹性极限: Elastic Limit 9＊.σs ----屈服极限: Yielding Stress 10＊.σb ----强度极限: Ultimate Stress 11. 延伸率: Percent Elongation12. 断面收缩率: Percent Reduction of Area 13. 塑性材料: Ductile Materials 14. 脆性材料: Brittle Materials 15. 铸铁:Cast iron§2.7 失效、安全系数和强度计算 Failure, Safety factor and Strengthcalculation1＊. 许用应力: Allowable Stress 2. 安全系数: Safety Factor 3＊. 强度条件: Strength Condition][max σσ≤=AF N4＊. 强度校核: Check strength][max σσ≤5＊. 截面设计: Section design][σNF A ≥6＊. 确定许可载荷:Determine allowable load][σA F N ≤§2.8 轴向拉伸或压缩时的变形 Deformation in Axial Tension orCompression1. 弹性变形: Elastic Deformation2. 塑性变形: Plastic Deformation3. 纵向应变: Longitudinal Strainll l l l -=∆=1ε 4. 横向应变: Lateral Straindd d d d -=∆=''ε5．线弹性变形:Linear Elastic Deformation6.泊松比:Poisson’s ratioεεμ'=7＊.弹性模量-E ：表示材料抵抗拉压变形的 能力 E - modulus of elasticity ：Indicates the capability of materials for resisting tension or compression 8＊.抗拉刚度-EA :表示构件抵抗拉压变形的能力EA -the axial rigidity: Indicates the capability of constructive members for resisting tension or compression 9＊. 胡克定律（Hooke’s Law ）:当应力不超过材料的比例极限时，应力与应变成正比.The stress is proportional to the strain within the elastic region.εσE =§2.12 应力集中的概念The Concept of Stress Concentration 1.由于截面尺寸的突然变化，使截面上的应力分布不再均匀，在某些部位出现远大于平均值的应力，称应力集中。
Discontinuities of cross section may result in high localized or concentrated stresses. 2. 理论应力集中系数K ：TheoreticalEA L F L N=∆Stress-concentration Factor - K§2.13剪切和挤压的实用计算Practical Calculation of Shear and Bearing 1＊. 剪切：Shear2.剪切面：Shearing Plane 3＊. 剪切面上的内力-剪力：Internal Force in Shearing Plane-Shearing Force4. 剪切的实用计算：Practical Calculation of Shear][ττ≤=AF S5. 挤压的实用计算：Practical Calculation of Bearing][bs bsbs A Fσσ≤=6. 挤压强度条件：工作中的挤压应力不应超过许用挤压应力。
Strength condition of bearing ：Working bearing stress should not exceed the allowable bearing stress.第三章 扭 转 Chapter Three Torsion§ 3.1 扭转的概念和实例 Concept and Examples of Torsion 1. 电动机: Generator 2. 涡轮: Turbine 3＊. 扭转的受力特点：杆件的两端作用着大小相等，方向相反，且作用面垂直于杆件轴线的力偶。
Characteristic of loads: Shaft is loaded by a torsional couple in planes that are perpendicular to the axis of the shaft. 4＊. 变形特点：杆件的任意两个横截面发生绕轴线的相对转动。
Characteristic of deformation: any two cross sections will twist along the axis. 5＊. 轴: Shaft§ 3.2外力偶矩的计算 扭矩和扭矩图 Calculation of the external torqueInternal torque and Its diagram1．扭转外力偶矩的计算：Calculation of the external torque 2＊. 扭矩：Internal Torque 3. 符号规定：Sign convention 4＊. 右手螺旋法则: Right hand screw rule 5＊. 扭矩图：Diagram of Internal Torque§ 3.3 纯剪切 Pure Shear1. 薄壁圆筒的扭转实验：Experiment of thin-walled circular tube under torsion2. 变形特点: Characters of deformations ： 截面间的距离不变;所有横截面的位置不变;所有纵向线转过了一个角度γ。