Investigations of the stress concentration in strip with single or double circular holes by the finite element methods (FEM)

ABSTRACT In this study, the stress concentration around the circular hole in an anisotropic finite strip- plate with a single or double holes in its structure has been examined under the considered boundary conditions in the framework of the exact equations of the theory of elasticity in the plane strain state with the help of finite elements method (FEM). The solution zone has been meshed with the use of triangular finite elements with six nodes and oblique edge around the circular holes and in the remaining region with the use of nine-node rectangular finite elements. All calculations in each finite element were carried out numerically. Due to the use of the displacement based finite elements method the only unknown at each node has been designed as the displacements. The stress functions which are found by using displacements obtained at the end of the FEM solution and discontinuous at boundary of finite elements have been made continuous by using variational recovery. All operations have been accomplished using Cartesian coordinate system. However, because of stress values at the polar coordinates are more suitable for interpretation of numerical results in thesis polar expressions of stresses are given. The effect of the geometric and material parameters of the strip-plate to the stress values under the considered case has been examined in detail and the numeric results have been presented in the form of tables and graphs. Key Words : - Stres Concentration, Finite Elements Method, Strip, Orthotrop, Anisotropy Vll