ENGR 220 Lecture 11 Chapter 6
Week 5 Recitation
Quiz Chp. 5, HW 6.4, 6.5, 6.10, 6.21
Mechanical Properties of Metal A. Stress and Strain 1. What are they 2. Why are they used instead of load and deformation B. Elastic Behavior 1. When loads are small how much deformation occurs 2. Which materials deform least C. Plastic 1. At what point does permanent deformation occurs. Elastic Deformation A. Process 1. Initial a) Original set up 2. Small Load a) Bonds stretch b) Do not break 3. Unload a) Returns to the initial length B. Reversible 1. Not permanent since the bonds are not broken a) Linear Elastic b) Non-Linear elastic Plastic Deformation A. Process 1. Initial a) Original set up 2. Larger load a) Bonds stretch b) Planes shear (1) Slide 3. Unload a) Stretching goes away (1) Elastic reformed b) Shearing stays (1) Deformation due to shearing Engineering Stress
11.
II1.
IV.
A. Two Forms 1. Tensile Stress 2. Shear Stress V. Engineering Strain A. Tensile Strai