Numerical calculation of stress concentration of various subsur-face and undercutting pit types

Abstract

In this study, the stress concentration effect of single subsurface (D type) pit types and undercutting (Etype) pit types with various pit depth and diameter has been investigated with respect to uniaxial loading by conducting a series of 3D stress analyses systematically. Finite element analyses have been conducted in order to determine the stress concentration factor of pits. Pit aspect ratio q/a and a/2c are the main parameters affecting the value of the stress concentration factor for subsurface types of pits. e/a and e/2c are also pit aspect ratios affecting the value of the stress concentration factor for undercutting types of pits. Some equations have been made to estimate the stress concentration factor depending on the geometrical parameters from the results of stress analyses. The stress concentration factor can be calculated using an equation obtained with a correlation coefficient (R-2) of 0.993 for D types (subsurface) pits. The stress concentration factor can also be calculated using an equation obtained with a correlation coefficient (R-2) of 0.995 for E types (subsurface) pits.