Creep behavior and modeling of high-density polyethylene (HDPE)

Creep behavior of high-density polyethylene (HDPE) was investigated. HDPE has many engineering applications in different industries such as piping systems, cable and wiring, automotive parts, storage containers, and biomedical implants. The temperatures chosen were 23, 53, and 82 °C based on the service temperature range for application in design of automotive fuel tanks. Creep strength decreased and creep strain as well as creep strain rate increased by increasing temperature. The Larson-Miller parameter widely used for metallic materials was able to correlate time to rupture, stress, and temperature data of HDPE. The Monkman-Grant relation was successfully used to correlate minimum creep rate and time to rupture. The Findley power law and time-stress superposition principle (TSS) were used to represent nonlinear viscoelastic creep curves. Some longer-term creep tests were also conducted at room temperature to evaluate the accuracy of extrapolation of the short-term creep test results to longer creep life predictions. The models used based on the data presented can be used in the design of parts and components made of HDPE where creep failure may be a concern