A New Protocol for Accelerated Screening of Long-Term Plasticity-Controlled Failure of Polyethylene Pipe Grades

In this study, a new experimental protocol to evaluate long-term, plasticity-controlled failure using short-term testing is validated on a high-density polyethylene (PE100) pipe grade. The protocol starts with the assessment of the strain rate dependence of the yield stress in uniaxial extension at various temperatures. Additional uniaxial compression tests are performed to characterize the influence of hydrostatic stress. The plastic flow kinetics are subsequently captured using a Ree-Eyring modification of the pressure-modified Eyring flow equation. In combination with the hypothesis that failure occurs at a critical amount of accumulated plastic strain, a versatile tool to predict time-to-failure is obtained. (C) 2016 Society of Plastics Engineers