AXAL TENSIONAND COMPRESSION
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AXAL TENSIONAND COMPRESSION s1-2 INTERNAL FORCE、 METHOD OF SECTION、 AXIAL FORCE AND ITS DIAGRAM l、 Internal force Internal force is the resultant of internal forces, which is acting mutual between two neighbour parts inside the body, caused by the external forces Fi F3 上康 F2 F
1、Internal force Internal force is the resultant of internal forces, which is acting mutually between two neighbour parts inside the body,caused by the external forces. §1–2 INTERNAL FORCE、METHOD OF SECTION、AXIAL FORCE AND ITS DIAGRAM 13
§1-2内力·截面法·轴力及轴力图 、内力 指由外力作用所引起的、物体内相邻部分之间分布内 力系的合成(附加内力)。 Fi F3 上康 F2 F 14
14 一、内力 指由外力作用所引起的、物体内相邻部分之间分布内 力系的合成（附加内力）。 §1–2 内力 · 截面法 · 轴力及轴力图
AXAL TENSIONAND COMPRESSION 2、 Method of section· axial force Calculation of the internal forces is the foundation to analyze the problems of strength, rigidity, stability etc. The general method to determine internal forces is the method of section 1). Basic steps of the method of section: O Cut off: Assume to separate the rod into two distinct parts in the section in which the internal forces are to be determined sUbstitute: Take arbitrary part and substitute the action of another part on it by the corresponding internal force in the cut-off section Equilibrium: Setup equilibrium equations for the remained part and determine the unknown internal forces according to the external forces acted on it (Here the internal forces in the cut-off section are the external forces for the remained part 15
2、Method of section · axial force Calculation of the internal forces is the foundation to analyze the problems of strength、rigidity、stability etc. The general method to determine internal forces is the method of section. 1). Basic steps of the method of section： ① Cut off：Assume to separate the rod into two distinct parts in the section in which the internal forces are to be determined. ②Substitute：Take arbitrary part and substitute the action of another part on it by the corresponding internal force in the cut-off section. ③Equilibrium：Set up equilibrium equations for the remained part and determine the unknown internal forces according to the external forces acted on it. （Here the internal forces in the cut-off section are the external forces for the remained part） 15