Double circular arc model based on average shear stress yield criterion and its application in the corroded pipe burst

Abstract

Corrosion is one of the major causes of damage in offshore and onshore pipes. Based on the double circular arc (DCA) model and the average shear stress yield (ASSY) criterion for isotropic hardening materials, a new burst pressure equation for corroded pipes is developed in this paper. The ASSY criterion is a weighted average of the maximum shear stress and the octahedral shear stress and it is adopted to predict the burst pressure of the pipelines with corrosion defects. The accuracy of our predictive equations is validated respectively by both the ideal and corroded pipes. Firstly, the burst pressure equation of a corroded pipe is degraded into an ideal pipe's. Then we compare the calculated results with the full-scale experimental data. The calculated results are consistent with the experimental data for the ideal pipes. Again, we make a comparison of the predicted burst pressures of corroded pipes with the ones from the elastic-plastic finite element method (FEM) and the experiment. The calculated results show a good agreement with the numerical calculations and experimental data for the corroded pipes. Our research reveals that the corrosion defects can decrease the burst pressure for a pipe; the yield criterion and the strain hardening exponent are crucial to accurately capture the burst pressure. Our research is beneficial to evaluate the integrity of the corroded pipes.