J-Integral and Tearing Modulus Estimates for Circumferentially Cracked Pipes in Torsion

Abstract

J -integral and tearing modulus analyses are developed for full circumference part-through cracks in pipes under torsion. The approach is based on the psuedo-potential energy interpretation of the J -integral. The paper develops estimation formula for the plastic component of the J -integral for the condition of net-section yielding in the cracked section of the pipe. The applied tearing modulus estimates are derived for deformation-controlled loading. Numerical results are presented for crack initiation and tearing instability that provide quantitative results for inferring safety of cracked nuclear piping.