Theoretical analysis of the effects of relative crack length and loading angle on the experimental results for cracked Brazilian disk testing

Based on the closed-form expressions of the stress intensity factors for a central cracked circular disk, four error transfer functions of the stress intensity factors were introduced in order to analyze the effect of the relative crack length and the error of loading angle on the experimental results for Brazilian disk testing. The analyzed results show that the precision of K I and K II are relevant on the relative crack length and the error of loading angle. Further analysis show that the error of loading angle Δ θ has a significant effect on the errors of K I and K II under mixed-mode loading condition, but Δ θ has nearly no effect on the error of K I under pure mode I loading condition and smaller effect on that of K II under pure mode II loading condition. Finally, the recommended range of the relative crack length is between 0.4 and 0.6.