CRACK GROWTH-BASED FATIGUE LIFE PREDICTION FOR AGING PIPELINE STEEL IN HYDROGEN WITH PRE-EXISTING CORROSION

Using existing pipeline infrastructure for hydrogen transport is under prime focus nationwide and globally. As a result, several studies were conducted under gaseous and electrochemically charged hydrogen environments. However, most existing studies focused on virgin material degradation under a hydrogen environment but did not include the effect of pre-existing damage due to aging, such as corrosion. This study focuses on a hydrogen-assisted fatigue crack growth model that can capture the growth rate behavior for various line pipe steels at various operating conditions. Pre-existing corrosion (both general material loss and pitting) effects are naturally included as surface irregularities in the form of roughness. Modified stress intensity factor solutions for surface roughness and crack growth kinetics function are integrated for fatigue life prediction. Model predictions are validated with collected experimental data from the open literature. Several future research directions are recommended based on the current findings.
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