Mixed-Mode Stress Intensity Factor Estimation of Inclined Cracks in an Unnotched Round Bar

The extent on mixed-mode stress intensity factor (SIF) of inclined multiple cracks in an unnotched bar has been investigated numerically. Opposite cracks with various crack depth ratios (a/d), crack aspect ratios (a/c) and inclination angles (θ) were considered. The geometry correction factor (Y) was calculated by considering the effect of mode-II and mode-III fracture. It was observed that, for short cracks [(a/d) = 0.1], as the inclination angle increases, SIF of mode-I decreases and conversely mode-III SIF increases. For short cracks in crack-2, as the inclination angle increases, the mode-I SIF decreases similar to crack-1, but the SIF of mode-III decreases as well. The mode-III contributes to a significant amount of SIF owing to the inclination of the crack. Regardless of the inclination angle, with an increase in the aspect ratio [a/c], the mode-I and mode-III SIF for both crack-1 and crack-2 decreases.