A cyclic cohesive zone model for predicting hydrogen assisted fatigue crack growth (FCG) of subsea pipeline steels

Abstract

A cyclic cohesive zone model for predicting hydrogen assisted fatigue crack growth is proposed, in which the degradation of cohesive strength and accumulated cohesive length is taken into account and an inverse Logistic formula is proposed for describing the degradation model of the accumulated cohesive length. A comparison between prediction results of the proposed model and experimental data of fatigue crack growth rates (FCGRs) of API 5L Grade B, X42 and X52 pipeline steels under hydrogen environment is then performed and the results show that the FCGRs predicted by the proposed model are in good agreement with the experimental data.