Review on lifetime predictions of polyethylene pipes: Limitations and trends

Reliable lifetime prediction of underground polyethylene (PE) pipes must be based on a more in-depth understanding of failure mechanisms and a more reliable extrapolation procedure of relatively short test data into longterm service environment. However, there still remain many limitations in the current lifetime prediction methods of PE pipes, such as the deviation of accelerated tests from operating conditions and the empiricism in prediction models. This paper summarizes the failure mechanisms of PE pipes and reviews the researches on lifetime prediction method from two aspects mechanical and chemical lifetime. A detailed presentation of limitations in current lifetime prediction methods are provided, including failure to consider the material aging and defects or imperfections, crack initiation time, crack tip plasticity and aging, diffusion-limited oxidation and nonlinear Arrhenius behavior. Potential trends of lifetime prediction of PE pipes are further discussed. The chemo-mechanically coupled model and crack layer (CL) model is proposed for the lifetime prediction to reduce the empiricism due to the diffusion-limited oxidation (DLO) or the transition from a continuous SCG to discontinuous.

Automated summary

This paper summarizes the failure mechanisms of underground polyethylene (PE) pipes and reviews the research on lifetime prediction methods from mechanical and chemical aspects. The paper highlights the limitations in current prediction methods and discusses potential trends in lifetime prediction of PE pipes, proposing a chemo-mechanically coupled model and crack layer (CL) model to reduce empiricism.