1. Chapter 1

2. §1.2 Mechanical Properties of Materials  Strength  Elasticity and Plasticity  Brittleness and Toughness

3. Definition  It refers to the material capacity of resisting breakage by the external force. Classifications of strength and formula  Classifications and formula of strength are listed in the flash. Strength

4. Formula of strength 请点击右键选择 “ 播放 ” 观看 Flash 动画

5. Elasticity and Elastic Materials It refers to the material property, in which the substance is deformed by the external force and restored when the external force is canceled. 1 2 Plasticity and Plastic Materials It refers to the material property, in which the substance is deformed by the external force, but it can keep the transformative shape and size and not bring crack with it when the external force is canceled. Elasticity and Plasticity

6. b a Deformation Load 0 A ab-elastic deformation Deformation curve ob-plastic deformation

7. 1 It refers to the material property, in which the substance is being destroyed suddenly without obvious plastic deformation to the extent of some external force. Deformation curve of brittle materials is showed in Fig1.2.1. Brittleness and Toughness

8. Brittle materials: stone, cement concrete, mortar, glass and pottery etc Load A Deformation Fig1.2.1 Deformation curve of brittle materials

9. 2 It refers to the material property, in which the substance can absorb a mass of energy and bring some deformation but not to be destroyed by the impact force and the shaky load. Tough materials: steel and wood etc Brittleness and Toughness