Analytical Method for the Calculation of J Parameter on Cracked Pipes Under Thermal Loading and Mechanical Plus Thermal Loading

This article deals with an analytical procedure to estimate J for a pipe submitted to a through thickness thermal transient. This procedure is based on an elastic J calculation and on the reference stress concept to determine the amplification due to plasticity: • The elastic J is deduced from an elastic F. E. calculation or a K_I handbook. A correction is then made to take into account the reduction of stresses due to plasticity. • The reference stress is deduced from a thermal stress and an elastic follow-up factor between the cracked and the uncracked sections. The formulation, for thermal loading or mechanical + thermal loading, and the validation procedure are presented. Results obtained by the formulation are in good agreement with F.E. calculations.