Stress intensity factor solutions for subsurface flaws in plates subjected to polynomial stress distributions

Lu, K. ; Katsuyama, Jinya  ; Li, Y. ; Iwamatsu, Fuminori*

Stress intensity factor (SIF) solutions for subsurface flaws near the free surface in plates were numerically investigated based on the finite element analyses. The flaws with aspect ratios = 0, 0.1, 0.2, 0.3, 0.4 and 0.5, the normalized ratios = 0, 0.1, 0.2, 0.4, 0.6 and 0.8 and = 0.01 and 0.1 were taken into account, where a is the half flaw depth, l is the flaw length, is the distance from the center of the subsurface flaw to the nearest free surface and t is the wall thickness. Fourth-order polynomial stress distributions in the thickness direction were considered. In addition, probabilistic fracture mechanics analyses were also performed and some example solutions obtained in this work were used to evaluate the conditional probability of failure of a reactor pressure vessel under a pressurized thermal shock event. The results indicated that the numerical SIF solutions calculated in this study are effective in engineering applications.