吉林大学《材料科学与工程基础》chapter 7.pptVIP

Chapter 7 Mechanical Properties Chapter 7Mechanical Properties 第七章 力学性能 Why How to Study Mechanical Properties? Learning Objectives Define engineering stress and engineering strain. State Hooke’s law, and note the conditions under which it is valid. Define Poisson’s ratio. Given an engineering stress–strain diagram, determine (a) the modulus of elasticity, (b) the yield strength (0.002 strain offset), and (c) the tensile strength, and (d) estimate the percent elongation. For the tensile deformation of a ductile cylindrical specimen, describe changes in specimen pro-file to the point of fracture. Compute ductility in terms of both percent elongation and percent reduction of area for a material that is loaded in tension to fracture. Compute the flexural strengths of ceramic rod specimens that have bent to fracture in three point loading. Make schematic plots of the three characteristic stress–strain behaviors observed for polymeric materials. Name the two most common hardness-testing techniques; note two differences between them. (a) Name and briefly describe the two different microhardness testing techniques, and (b) cite situations for which these techniques are generally used. Compute the working stress for a ductile material. 材料科学基础的内容材料科学与工程(MSE)的整体概念 Composition Synthesis 7.1 INTRODUCTION Mechanical properties: The mechanical behavior of a material reflects the relationship between its response or deformation to an applied load or force. Important mechanical properties: strength, hardness, ductility, toughness. 7.2 CONCEPTS OF STRESS AND STRAIN Ways that load applied: Tension, Compression Shear torsion 7.2 CONCEPTS OF STRESS AND STRAIN TENSION TESTS: 7.2 CONCEPTS OF STRESS AND STRAIN COMPRESSION TESTS: SHEAR AND TORSIONAL TESTS: 7.2 CONCEPTS OF STRESS AND STRAIN GEOMETRIC CONSIDERATIONS OF THE STRESS STATE: 7.3 STRESS–STRAIN BEHAVIOR Stress–strain diagram and modulus of elasticity: 7.3 STRESS–STRAIN BEHAVIOR Force versus interatomic separation to ex