Constraint Effects and Crack Driving Forces in Surface Cracked Pipes Subjected to Reeling

Abstract

This study reports an extensive set of non-linear analyses of circumferentially cracked pipe subjected to reeling. To describe the evolving levels of stress triaxiality ahead of crack front with increased loading, the present work employs the J-Q methodology to characterize fracture response for different crack configurations. The numerical simulations demonstrate that large values of crack-tip driving forces arise in cracked pipes under reeling which, at the same time, are accompanied by strong constraint loss at the crack-tip. Moreover, plane-strain analyses of clamped SE(T) fracture specimens reveal crack-tip conditions which are more similar to cracked pipes subjected to reeling with identical (relative) crack depths, which contrasts sharply to conditions displayed by standard fracture specimens such as the C(T) specimen. Overall, the results reported here encourage further investigations in the development and utilization of constraint-designed SE(T) specimens under clamp conditions in fracture assessments of cracked pipes subjected to reeling.