Chapter 1: Introduction

Sheet forming parts has become a successful and well-established process for metals, alloys, polymers, ceramics and composites. The goal is to control the deformation during forming process and ensure minimum variation of local zone, avoidance of cracking (failure), dimensional control, and elimination of defects. the goal of this book is to make inroads on the understanding of the hardening behavior and propose a modification of hardening behavior to predict correctly the tension-compression curve in simple way. In the next section, we review the pertinent literature. We believe that better understanding the role of hardening behavior is the key to better predict the tension-compression and compression-tension curves. The major goal of this dissertation is to give the simple way to determine correctly stress-strain curves with revered load, and then predict fracture obeyed ductile fracture criterion, therefore to provide a design tool to control and optimize the sheet forming operations.