Dynamic Fracture Behavior of High Strength Pipeline Steel

The occurrence of a crack propagating along a pipeline is a catastrophic event, which involves both economic losses and environmental damage. Therefore, the study of the fracture initiation and propagation properties of a pipeline is an essential part of its integrity assessment. Fracture prediction, however, is a challenging task, since it requires knowledge of the interaction between the dynamic forces driving crack growth, and the resistance forces opposing fracture propagation. Moreover, plenty of material properties should be taken into account. Aiming at a better understanding of the plastic hardening, damage and fracture properties of an API 5L X70 pipeline steel, and how these are affected by the strain rate, in present contribution, a comprehensive set of test results is presented. The program includes static and dynamic tensile tests on smooth and notched samples, and compression tests on cylindrical samples. Test result analysis is supported by finite element (FE) modelling. As such, the study aims at providing data needed for both fundamental material research and constitutive material modelling.