Plasticity: Engineering vs True Stress and Strain

This lecture discusses the difference between engineering and true stress and strain measures, focusing on the conversion process and the implications for material behavior. It covers the strain measures obtained from stress-strain curves, the conversion formulas, and the use of power law hardening models. The instructor explains the significance of measuring uniaxial engineering stress vs. strain in the lab and the transition to true stress vs. strain. The lecture concludes with a practical example comparing true material behavior with engineering behavior, emphasizing the importance of accurate material models for complex engineering problems.