Crack layer modeling of overload-induced slow crack growth retardation of high-density polyethylene

The existing crack layer model theoretically mimics the discontinuous slow crack growth behavior of high-density polyethylene; however, it can only be applied to cyclic loads of constant amplitude or constant load conditions. Most load-bearing components, such as pressurized pipes, are subjected to variable-amplitude loads with unexpected overloads under their service conditions. Thus, the effect of variable amplitude loading on the slow crack growth behavior and lifespans should be understood. In this study, a modified crack layer model was developed to simulate the overload-induced retardation behavior of discontinuous slow crack growth of pipe-grade high-density polyethylene for the first time. The developed model was verified by conducting a sensitivity study on several input parameters and comparing the results with experimental results. The measured retardation results were successfully reconstructed using the proposed model in high accuracy. This study expands the applicability of the crack layer model for the reliable use of pipe-grade high-density polyethylene under various fatigue loading conditions, including unexpected overloads.