82-1 Plane stress problem and plane strain problem In actual problem, it is strictly saying that any elastic body whose external force for suffering is a space system of forces is generally the space object. However, when both the shape and force circumstance of the elastic body for investigating have their own certain characteristics. As long as the abstraction of the mechanics is handled together with appropriate simplification, it can be concluded as the elasticity plane problem The plane problem is divided into the plane stress problem and plane strain problem 1. Plane stress problem Equal thickness lamella bears the surface force that parallels with plate face and don t change along the thickness at the same time so does the volumetric force y 02=0x=0x2=0 Fig2-1 55 1.Plane stress problem §2-1 Plane stress problem and plane strain problem In actual problem,it is strictly saying that any elastic body whose external force for suffering is a space system of forces is generally the space object.However,when both the shape and force circumstance of the elastic body for investigating have their own certain characteristics.As long as the abstraction of the mechanics is handled together with appropriate simplification,it can be concluded as the elasticity plane problem. The plane problem is divided into the plane stress problem and plane strain problem. Equal thickness lamella bears the surface force that parallels with plate face and don’t change along the thickness.At the same time,so does the volumetric force. σz = 0 τzx = 0 τzy = 0 Fig.2－1