华中师范大学《材料力学》课件-第2章轴向拉压.pdfVIP

华中师范大学《材料力学》 MMechhaniics off MMatterii l als Chapter 2 Axial Tension(Compression), Mechanical PPropertities off MMatteriialls andd ShShear §2-1 Axial Force and Diagram of Axial Force §2-2 Normal Stress on Cross Section in Tension (Compression) §2-3 Stress on the Inclined Section §2-4 Stress Element of Members in Tension(Compression) §2-5 Mechanical Properties of Materials in Tension §2-6 Mechanical Properties of Materials in Compression §2-7 Allowable Stress and Strength Condition; §2-8 Deformation of Members in Tension(Compression) §2-9 Stress Concentration §2-10 Shear and Practical Calculation of Strength of Connectors §§22-1111 PurePure ShearShear §2-12 Hooke’s Law in Shear §§22-11 AAxiiall FForce andd DiDiagram off AAxiiall FForce 一、实例实例 Practical exampples 3 4 二、轴向拉伸与压缩的变形特点轴向拉伸与压缩的变形特点： Characteristic of loads and deformation 受力特点: 外力的合力作用线与杆的轴线重合。 CharacteristicCharacteristic ofof thethe externalexternal force:force: TheThe actingacting lineline ofof thethe resultant of external forces is coincided with the axis of the bar. 变形特点: 轴向伸缩伴随横向缩扩。 轴向拉伸轴向拉伸 (axial tension)) ：轴向伸长轴向伸长，，横向缩短横向缩短。 轴向压缩(axial compress) ：轴向缩短，横向变粗。 拉伸 压缩 F FF FF FF 9 三、①横截面上的内力--轴力FN （Axial force , Normal force, FN ） 轴力:沿杆件轴向作用的内力，记作FN 。 Axial force: Internal force acting on cross-section along the axle, designated as F . N ②采用截面法求轴力： Determine FN by method of sections. m