Singularity and Distribution of Stresses Around Tip of a Shallow Crack

摘要

This report concerns a mode I edge crack of acusp-type morphology, analytically deriving the increased stressintensity due to the presence of the traction-free surface. Thesurface effect upon the stress intensity KI is shown to be given bya factor β=3·2-3/2 in KI=βσ[ЛС]1/2, where σ and c arethe mode I stress applied at infinity and the surfacecrack depth, respectively. The derived stressintensity is 6 percent greater, which means aneffective crack length is 12.5 percent greater, thanthat of an internal crack with a half crack lengthequal to the surface crack depth, and comparesinferiorly with 1.1215σ[πС]1/2 for an edge crackwith rectangular corners and with depth c.