A new evaluation method to calculate crack initiation limit with modified crack aspect ratios in notched specimen of carbon steels

摘要

Aspect ratio is a key factor to calculate stress intensity factor (SIF) K using fracture mechanics. While cracks are approximated to be semi-circle or semi-ellipse for simply evaluation, their shapes are changed by stress concentration source. In this study, a new method to modify aspect ratio of a crack at a notch root is proposed. Modified aspect ratio in this method succeeded to decrease prediction error of fatigue crack initiation stress, σ_(w1) which was calculated using experimental value.