On the environmental similitude for fracture in the SENT specimen and a cracked hydrogen gas pipeline

We investigate the use of laboratory fracture specimens to ascertain the resistance to hydrogen embrittlement of a hydrogen pipeline with an axial crack on the inner diameter (ID) surface. In particular, we study the interaction of hydrogen with material elastoplasticity in single edge notch tension (SENT) specimens loaded in hydrogen gas at a pressure of 15 MPa. We find that the transient and steady state hydrogen concentration fields in the neighborhood of the crack tip in the SENT specimen and the real-life pipeline are essentially the same. This environmental similitude warrants the use of the SENT specimen in a gaseous hydrogen environment to examine the compatibility of steel pipelines with hydrogen.