Introduction to Welding Mechanics

The welding phenomenon is complicated and interdisciplinary among three categories: metallurgy, welding process, and mechanics. The main purpose of this book is to provide methods for how to analyze the mechanical behavior during welding by the finite element method using a computer. The method is referred to as computational welding mechanics. In this first chapter, basic knowledge on welding and welding mechanics is introduced. Before discussing details of computational welding mechanics, using a simple three-bar model, transient welding stress and distortion under thermal processes are analyzed with the aid of the basic theory of thermal elastic-plastic analysis. The production mechanism of residual stress is explained by the concept of inherent strain (plastic strain). Then, reproduction of residual stress by inherent strain and inverse analysis for inherent strain from residual stress are illustrated. Numerical examples of residual stress, inherent strain, and inherent displacement are presented.