The influence of a non-aligned semi-elliptical surface crack on a quarter-circle corner crack in an infinitely large plate under uniaxial tension

Abstract

Fitness-for-Service codes require the evaluation of non-aligned multiple cracks in various practical applications. For on-site inspection, decision needs to be made on whether the cracks should be treated as coalesced or separate multiple cracks in case of non-aligned parallel cracks,. In the existing literature, criteria and standards for the adjustment of multiple nonaligned cracks are very source dependent, and those criteria and standards are often derived from on-site service experience without rigorous and systematic verification. Based on this observation, the authors previously reported on the effect between an edge and an embedded parallel crack in 2-D scenarios and, more recently, in 3-D scenarios of circular cracks. Since realistic crack configurations detected using non-destructive methods are generally 3-D in nature, the study of 3-D effect of non-aligned cracks with different shapes is deemed necessary in order to obtain more practical guidance in the usage of rules speculated in Fitness-for-Service codes. In this study, the effect of a semi-elliptic surface crack on a quarter-circle corner crack in an infinitely large plate under uniaxial tension was investigated. To keep this study more focused, the size of the quarter-circle corner crack was kept constant. A detailed analysis was then given to the crack shape effect of the embedded semi-elliptic cracks on the fixed quarter-circle corner crack. The analysis is repeated for various combinations of separation distances S and H between the two cracks. The results from this study are collectively significant to the understanding of the correlation between the criteria and standards in Fitness-for-Service community and the consequence of their usage in engineering practice.