Crack shape idealization of a complex crack to an equivalent through-wall crack using net-section collapse

This paper proposes a crack shape idealization method based on the net-section collapse concept to predict the fracture behavior of pipes with complex cracks. The proposed method assumes that an idealized through-wall cracked pipe has an identical limit load to a pipe with a complex crack, given the same outer diameter and through-wall crack angle. By applying this approach, complex cracks can be idealized into simpler through-wall cracks. The comparison of limit loads between the idealized through-wall cracked pipe and the complex cracked pipe demonstrates good agreement. For experimental validation, the method was used to predict the maximum load of pipes with complex cracks, and the results were compared with actual pipe test data. Using the crack driving force diagram method, the predicted maximum load showed variations of 1 %–32 % compared to experimental results. Despite these variations, the proposed method provides a practical and reliable approach for predicting the maximum load of complex cracked pipes in both fully plastic and elastic-plastic regions, simplifying analysis while maintaining accuracy.