A High-Accuracy Empirical Formula for the Strain Concentration Factor in Countersunk Holes

This paper presents a modified high-accuracy empirical formula for the strain concentration factor in centrally-placed countersunk holes isotropic plate under uniaxial tension. Finite Element Method (FEM) was used to investigate effect of problem geometric parameters including, width and thickness, as well hole radius, countersinking depth angle on factor. The important influence Poisson’s ratio also thoroughly discussed. Based FEM-generated data nonlinear regression, general high-precision equation developed. formulation process based producing computing with unknown coefficients. Such coefficients are determined by minimizing relative error between fitted FE using least squares method. results this newly-developed were validated FEA. comparison showed high accuracy present evaluating approximate less than 7%. Besides, efficiently employed test various material value holes. compared older available literature. proved much higher especially deeper larger previously published formula.