A modified cyclic cohesive zone model for low-cycle fatigue crack initiation prediction for subsea pipelines under mode I loading

Abstract

A modified cyclic cohesive zone model (CCZM) is developed for low-cycle fatigue crack initiation prediction for subsea pipelines. The traction and separation law in the model is modified by employing a piecewise function and linear softening for improving the computational convergence but maintaining the material nonlinearity. The validity of the modified model is evaluated with experimental results of two full-scale pipe specimens and also the results estimated by six published models. An engineering application is further presented to demonstrate the capability of the model and a parametric study is performed for investigating the impact of model parameters on model prediction.