Development of mechanochemical degradation induced slow crack growth model for high density polyethylene in cracked round bar specimen

Under certain condition, high density polyethylene exhibits unique discontinuous slow crack growth patterns owing to a process zone in front of the crack tip. Additionally, it undergoes stress corrosion cracking in the oxidative environment, which significantly reduces its lifetime. In this study, a theoretical model describing the stress corrosion crack growth behavior of cracked round bar specimens is developed. The proposed model simulates the discontinuous slow crack growth behavior under fatigue loading within an oxidative environment. The diffusion of the oxidant at the crack tip and the mechanochemical degradation of the process zone medium are simulated. The proposed model is validated via a parametric study performed on several input parameters, as well as via a comparison with experimental results.