Failure assessment of corroded ultra-high strength pipelines under combined axial tensile loads and internal pressure

Abstract

The failure of corroded ultra-high-strength steel (X100 and X120) pipelines under combined axial loads and internal pressure is investigated numerically by finite element analyses, and an empirical model is proposed for burst strength prediction. The finite element structural models are constructed with uniformly oriented axial defects and consider material non-linearity. After validating the finite element models against test data of intact and corroded ultra-high-strength pipes, they are used to study the effect of axial tensile force on burst strength. Extensive parametric analyses are then conducted to investigate the influence of corrosion defect parameters on the burst strength under combined loading. The results revealed that both axial tension and corrosion defect can significantly reduce the burst strength of UHS pipe. Later, the results of the parametric analysis are used to develop an empirical model for burst strength prediction of ultra-high-strength steel corroded pipelines subjected to combined loading. Finally, the model's prediction capability is validated by comparisons with other available models.