Abstract: Laboratory tests were performed to investigate the time-dependent stress behavior of polyethylene(PE) pipes under mechanical loading conditions. Analytical methods using convolution integrals and numerical modeling using finite elements were employed to model stress relaxation behavior. It showed that under small strain, the new PE viscoelasticity constitutive model which using Boltzmann superposition principle could be used to predict the relaxation behavior of PE pipe. With the support of material parameters, using the finite element method could effectively analyze the viscoelastic behavior of PE material.

Key words: polyethylene, pipe, stress relaxation, viscoelasticity, finite element method