The Role of Crazing in the Impact Fracture Toughness of PE Pipe Grades [PE]

Author(s) : Beech, Clutton

Design of pipe systems for lifetimes in excess of 100 years depends on accelerated testing of pipe at different temperatures, and standard extrapolation methods for assessment of the minimum required strength. However resistance to slow crack growth is an essential parameter to take into account for the development of...

Author(s) : Beech, Ferguson, Clutton

Design of pipe systems for 50 year lifetimes depends on accelerated testing of pipe at different temperatures and standard extrapolation methods for assessment of whether the minimum required strength is achieved. Further acceleration is used in the notched pipe test (NPT), which is a medium term (up to 1000 hour)...

Author(s) : Clutton, Rose, Capaccio

The development of pipe grades requires the careful balance of several mechanical properties, of which two of the most important are the resistance to slow crack growth (SCG) and rapid crack propagation (RCP). In this paper, we present small-scale tests which enable the rapid assessment of these properties. These...

Author(s) : Rose, Channell, Palmer

A series of PE 80 and PE 100 materials have been investigated to determine whether there exists a link between resistance to slow crack growth as measured by notched pipe test and creep of macroscopic oriented samples. Preliminary results suggests that there is a correlation between a single creep parameter and...

Author(s) : Channell, Cawood, Capaccio

A critical appraisal has been carried out of the creep fracture of the fibrils in the pre-crack damage zone (craze) of polyethylene homo and copolymers. It has been shown that by assuming that the fibrils are drawn to the natural draw ratio of the material, a clear correlation can be established between the creep rate...

Author(s) : Clutton, Dear, Channell

Two novel techniques have been applied to the problem of determining the fracture toughness of polyethylene appropriate to the situation of rapid crack propagation in pipe systems.Agreement is found between the data from the two methods used for evaluating four grades of polyethylene of widely different toughness. By...