Failure assessment diagram analysis of high density polyethylene pipes

Abstract

This paper presents an analysis of failure assessment diagram for PE4710 grade high density polyethylene pipes, which are recently concerned to use in the nuclear industry. Available test data of tensile, single edge notched tension specimens and pressurised pipes are summarised and suitably characterised for use in the failure assessment diagram in R6 procedure. Critical crack lengths and failure mode for the pressurised pipes and single edge notched tension specimens are determined under sustained load and compared with test results. Based on the concept of linear elastic fracture mechanics, a slow crack growth rate of PE4710 at 95°C is obtained excluding crack initiation time. To consider the effect of temperature on slow crack growth rate, a shift method is introduced. Remaining life is calculated against the crack margin and compared with the failure time.