2016工程力学-材料力学（高教版）教案：第三章 扭 转 .docVIP

第三章 扭 转 1Mechanics of Materials23§ 3–1 SUMMARY§ 3–2 EXTERNAL TORQUE OF A TRANSMISSION SHAFT INTERNALTORQUE AND DIAGRAMS§ 3–3 TORSION OF THIN-WALLED HOLLOW SHAFTS§ 3–4 STRESSES OF CIRCULAR SHAFTS IN TORSION · STRENGTHCONDITIONS§ 3–5 DEFORMATIONS OF A CIRCULAR SHAFT IN TORSION ?RIGIDITYCONDITIONS?3? STATICALLY INDETERMINATE PROBLEMS OF CIRCULARSHAFTS IN TORSION?3? STAIN ENERGY OF CIRCULAR SHAFTS IN TORSION?3? STRESSES AND DEFORMATIONS OF NONCIRCULAR SHAFTS INFREE TORSION?3? STRESSES OF OPENED AND CLOSED RODS WITH THIN WALLEDSECTIONS IN FREE TORSIONCHAPER 3 TORSION4§ 3–1 概述§ 3–2 传动轴的外力偶矩 · 扭矩及扭矩图§ 3–3 薄壁圆筒的扭转§ 3–4 等直圆杆在扭转时的应力 · 强度条件§ 3–5 等直圆杆在扭转时的变形 · 刚度条件§ 3–6 等直圆杆的扭转超静定问题§ 3–7 等直圆杆在扭转时的应变能§ 3–8 非圆截面等直杆在自由扭转时的应力和变形§ 3–9 开口和闭口薄壁截面杆在自由扭转时的应力第三章 扭 转5§ 3–1 SUMMARYShaft,In engineering the members of which deformations aremainly torsion,Such as transmission shafts in machines,drill rodsin oil-drilling rigs etc,Torsion,Resultant of the external forces is a force couple andits acting plane is perpendicular to the axis of the shaft,Underthis case the deformation of the rod is torsion,A B Om m? OBA ?6§ 3–1 概 述轴,工程中以扭转为主要变形的构件。如：机器中的传动轴,石油钻机中的钻杆等。扭转,外力的合力为一力偶，且力偶的作用面与直杆的轴线垂直，杆发生的变形为扭转变形。A B Om m? OBA ?7The angle of twist (?),The angle of rotation of one sectionwith respect to another,Shearing strain (? ),The change of a right anglebetween two straight lines,m m? OBA ?8扭转角（ ?）,任意两截面绕轴线转动而发生的角位移。剪应变（ ?）,直角的改变量。m m? OBA ?9Practical examples in engineeringTransmission shaft10工程实例11§ 3–2 EXTERNAL TORQUE OF A TRANSMISSION SHAFTINTERNAL TORQUE AND ITS DIAGRAM1,External torque of a transmission shaft The relationbetween the transmission power,revolution and external torqueof the transmission shaft,m)( k N559 ?? nP.mm)( k N0 2 47 ?? nP.mm)( k N1217 ?? nP.mwhere,P - power,unit,kilowatt (kW)n ?rotational speed,unit,r/min or（ rpm）where,P - power,unit,horsepower (HP)n – rotational speed,unit,