Two-dimensional weight function of stress intensity factors for corner cracks emanating from a circular hole

Abstract

The weight function method is adopted to calculate stress intensity factors along the corner crack front rather than at only two end points, which are pre-requisites in evaluating fatigue growth of corner cracks emanating from a circular hole. Two-dimensional weight function is derived for corner cracks emanating from a circular hole, based on reference stress intensity factors modified by Newman (2018) and corresponding accurate stress distribution on virtual crack face formulized by authors (Guo and Guo, 2019). The obtained weight function is validated against numerical results in the literature and finite element calculations and shows high accuracy. For quick fatigue crack growth prediction in engineering structures, explicit formulae are obtained for typical corner crack shapes with wide ranges of aspect ratio 0.2 ≤ a/c ≤ 2, crack depth ratio 0.1 ≤ a/B ≤ 0.95, crack front angular parameter 0.05 ≤ 2ϕ/π ≤ 0.95 and plate thickness to hole radius ratio B/R = 2. The process can be thereby extended to the estimation of stress intensity factors for corner cracks emanating from a circular hole contained in complicated structures under arbitrary stress distribution.