Basics of Elastic Theory

In this chapter, the author touches on the basics of elasticity theory. In general, the finite element method (FEM) is the most frequently used numerical analysis method as a simulation technique in the strength design and structural design of machines and structures. This analysis by the FEM is based on the elasticity theory. In order to understand viscoelasticity, its analysis method, and the basic formulas and formulation of viscoelasticity, it is very useful to first know the basic formulas and concepts of elastic theory. The author also discusses the three‐dimensional stress field. However, in stress analysis, it is not necessary to analyze everything as a three‐dimensional problem, and in some cases it is sufficient to analyze it as a two‐dimensional stress problem. In two‐dimensional stress, it is necessary to distinguish between plane stress and plane strain in the numerical analysis.