Stress Intensity Factors for Notched Configurations

Abstract

A method is presented for approximating stress intensity factors for notched-configurations without cracks. It is expected that estimates obtained from such analyses, which are outlined in the text and detailed in the Appendix, should be useful in estimating the failure load in a notched structure behaving in an idealized elastic manner. Additionally, this approach will allow an estimate of the magnitude of load required to precrack fracture toughness specimens having crack starter notches. Several notch geometries and loadings are investigated, such as a V-notch, to first illustrate the method of analysis and compare results with those in the literature and to also establish merit and accuracy limits of the method. Two additional cases are then solved, both for finite width tensile sheets, one having symmetric U-notches and the other employing a central slot with finite radii at each end. Both cases are reduced to their end limit: a U-notch in a sheet of semi-infinite width and a circular hole in an infinitely wide sheet. The resulting approximations agree well with limited available data. Finally, to aid the experimentalist who either uses the compliance approach or a photoelastic analysis to obtain stress intensity factors, the question of how deep or how long a side-edge U-notch or a central slot compared to its radius should be to simulate a crack, is provided.