Analytical expressions of the influence functions for accuracy and versatility improvement in the hole-drilling method

Abstract

Analytical expressions of the influence functions suitable for obtaining variable through-thickness residual stresses by the hole-drilling method are proposed. They were determined by interpolating the results of accurate finite element simulations of the experimental arrangement as prescribed by the ASTM standard. The effects of the geometrical parameters and material properties were included. The influence functions allow the relaxed strain measured by the strain gauge rosette to be directly calculated for a general residual stress distribution. With no interpolation of tabular values, they can be employed to evaluate the coefficients required for the application of the integral method. It is also shown how the influence functions can be used to obtain residual stress distribution on the basis of a fully general series expansion.