ELLIPTIC-ARC SURFACE CRACKS IN ROUND BARS

The crack aspect ratio influence on the stress-intensity factor of elliptical-arc edge flaws in solid round bars under tension or bending loading is discussed. The relative crack depth xi = a/D between the depth a of the crack's deepest point and the bar diameter D ranges from 0.1 to 0.6, while the aspect ratio a/b of the flaw is made to vary from 0.0 (straight crack front) to 1.0 (circular-are crack front). For each value of xi being considered, the maximum stress-intensity factor is attained in correspondence to the deepest point on the crack front in the case of a/b = 0.0, while it is attained near the external surface in the case of a/b = 1.0. For intermediate aspect ratios, the stress-intensity factor presents the maximum value at the crack's deepest point for xi less-than-or-equal-to xi(CR) and near the free surface for xi greater-than-or-equal-to xi(CR), with the critical relative crack depth xi(CR) getting lower and lower as the parameter a/b is increased.