2016工程力学-材料力学（高教版）教案：第二章 剪切 .docVIP

第二章 剪切 Mechanics of MaterialsCHAPTER 2 SHEAR§ 2－ 1 STRENGTH CALCULATION ABOUT SHEARAND BEARING OF CONNECTING MEMBERSEXCERCISE LESSONS OF SHEAR AND BEARING第二章 剪 切§ 2－ 1 连接件的剪切与挤压强度计算Production of the shearing stress剪应力的产生§ 2－ 1 STRENGTH CALCULATION ABOUT SHEAR ANDBEARING OF CONNECTING MEMBERS1,Characteristics of loads and deformation of connecting members,1)Connecting memberThe structure member that connects one member to another is called theconnecting member,Such as,bolts,rivets,keys etc,The connectingmember is small,but it plays the role of passing loads,Characteristic,It canpass general loads and can bedismounted,P Pbolt§ 2－ 1 连接件的剪切与挤压强度计算一、连接件的受力特点和变形特点,1、连接件在构件连接处起连接作用的部件，称为 连接件 。例如：螺栓、铆钉、键等。连接件虽小，却起着传递载荷的作用。特点：可传递一般 力,可拆卸。 PP螺栓P Privet Characteristic,It can pass general loads,but can not be dismounted.for example,the truss in a bridge is connected by it,no gapCharacteristic,It can pass torques,mShaftKeyGearmP P铆钉特点：可传递一般 力，不可拆卸。如桥梁桁架结点处用它连接。无间隙m轴键齿轮特点：传递扭矩。m2)Characteristics of loads and deformation,n n（ Resultant）（ Resultant）PPUse a rivet as an example,① Characteristic of loads,The rivet is subjected to two equal andopposite forces,The acting lines of thesetwo forces are very close,② Characteristic of deformation,Two parts subjected to two equal andopposite forces tend to shift over one anotheralong the junction plane of two forces,2、受力特点和变形特点,n n（合力）（合力）PP以铆钉为例,① 受力特点,构件受两组大小相等、方向相反、作用线相距很近（差一个几何平面）的平行力系作用。② 变形特点,构件沿两组平行力系的交界面发生相对错动。n n（ Resultant ）（ ResultantPP③ Shearing plane,The plane along which two parts of themember tend to shift over one another,Suchas n– n,④ Internal force on shearing plane,Internal force — Shearing force Q, itsacting line is parallel to the shearing plane,Pn nQShearingplanen n（合力）（合力）PP③ 剪切面,构件将发生相互的错动面，如n– n 。④ 剪切面上的内力,内力 — 剪力 Q,其作用线与剪切面平行。Pn nQ 剪切面n n(Resultant )(Resultant ）PP3)Three kinds of breakage at joint,① Fai