Interaction behavior for multiple embedded cracks subjected to bending load in creep regimes

Abstract

Multiple cracks grow from pre-existing defects during the manufacturing/installation process or from small cracks initiated are primary concerns in evaluating the structural integrity. In this study, the interaction behavior for coplanar multiple embedded cracks subjected to bending load in creep regimes was studied using numerical simulation approach. Influences of crack configurations (crack shape, crack depth and crack distance) and creep properties on creep interaction factor and C* distribution along the embedded cracks were evaluated based on the three-dimensional finite element solutions. Due to the interaction among the multiple cracks, the C* distribution was asymmetric along the crack front and the C* values were pronounced as the cracks approached each other. Moreover, crack depth, crack distance and creep exponent significantly affected the creep interaction factor and crack shape had limited influence. However, the maximum creep interaction factor did not coincide with the maximum C* values occurring along the crack front. The creep interaction factor determined by the average C* values along the crack front was employed to represent the intensity effect of multiple embedded cracks on the crack growth behavior. Finally, an empirical relation was proposed for estimating crack creep interaction factors of embedded cracks.