Probabilistic fatigue crack propagation assessment of hydrogen pipelines with weld toe cracks

Kurzfassung

Establishing hydrogen infrastructures has become necessary in building renewable energy networks for hydrogen usage; especially pipelines for the transmission of distribution of hydrogen gas. Being highly flammable gas, failure of hydrogen pipelines is forestalled by taking preventive measures; structural inspections, maintenance, and repairs. From previous research on structural integrity, it was revealed that hydrogen-assisted fatigue crack growth (FCG) is one of the threatening failure mechanisms in hydrogen pipelines. However, there are data uncertainties in the evaluation of FCG, especially material parameters exposed to hydrogen due to the limited published data currently. To deal with such uncertainties in material data, a probabilistic FCG model of hydrogen pipelines considering variable amplitude loadings (VAL) due to internal pressure fluctuations is developed in this study. Surface cracks on the parent metal and weld toe area of pipelines are considered as a case study to investigate the results provided by the developed computational model. The stress intensity factors of pipelines subjected to internal pressure are calculated using closed-form solutions. Probabilistic analysis is carried out following the Monte Carlo method. The developed FCG model in the Python environment provides the probabilistic fatigue life values of hydrogen pipelines subjected to internal pressure VAL.