2018 Las-Vegas : Extrusion of thick wall pipes using a new bimodal PE 4710/PE 100 resin
Author(s) : Vivek Rohatg, Gregor Hiesgen, Mark J. Lamborn, Ashish M. Sukhadia, Douglas E. Simpson, David W. Borrego, Pamela L. Maeger
Maintaining dimensions within specifications is problematic for the extrusion of large diameter thick-wall polyethylene (PE) pipe (> 75 mm wall) due to sag caused by insufficient resin melt strength. However, sag can be controlled through careful resin selection and optimization of the pipe cooling process. This paper...
2006 Washington DC : Rapid Crack Propagation in Loosely Fitted PE Liner Pipe
Author(s) : Leevers, Henderson, Pereira
Laboratory-scale S4 tests have been used to determine whether it would be possible, at any
realistic working pressure, for a loosely-fitted PE liner within a rigid host pipe to fail by
Rapid Crack Propagation (RCP). The standard ISO 13477 S4 method was modified by
replacement of the containment ring cage by a rigid,...
2006 Washington DC : S4 Critical Pressure and Critical Temperature
Author(s) : Maeger, Vanspeybroeck, Lamborn, Mamoun, Leevers, Oliphant
As polyethylene pressure pipes enter the global marketplace under an ever-wider range of
operating conditions, there is increasing emphasis on their rapid crack propagation
performance. It is important that both producers and end-users are able to rely on the
robustness of the rapid crack propagation test results and...
2004 Milan : S4 critical temperature tests: procedure and interpretation
Author(s) : Patrick Leevers
International Standard ISO 13477 defines the ‘S4’ RCP test itself, and specifies two
procedures which use it. The first procedure, already well embedded in referring standards,
evaluates a critical pressure at constant temperature (usually 0°C) below which RCP arrests.
The second procedure evaluates, at constant...
2001 Munich : Fully Predictive Model of RCP in Plastics Pipes
Author(s) : Ivankovic, Tropsa, Jasak, Leevers
This work presents a 3D coupled solid-fluid model for predicting fast failures in pressurised
plastic pipes. It is developed within a unified computational procedure where both solid
pipe and pressurising media are discretised using the Finite Volume method. The coupling
is achieved across the pipe-fluid interface...
2001 Munich : The Ductile-Brittle Transition in Pipe-Grade PE
Author(s) : Leevers, Moreno, Paizis
The resistance of PE pipes to rapid crack propagation depends strongly on temperature.
The critical pressure measured using ISO 13477 ‘S4’ tests increases abruptly above a
transition temperature Tc. For PE100 grades Tc has become a primary index of quality : it
must remain below 0°C despite a tendency to increase...
1998 Gothenburg : Ductile deformation in Pipe Grade PE
Author(s) : Hillmansen, Davis, Leevers
Rapid Crack Propagation in PE-100 gas pipes is governed primarily by a brittle-tough transition temperature
TBT,above which ductile deformation will absorb energy and promptly arrest a fast-running brittle crack. Even at
low temperatures, a layer of plastically deformed material is formed at the pipe bore during...
1998 Gothenburg : Process and Property Interactions in PE Pipelines
Author(s) : Davis, Greenshields, Dabas, Leevers
The study of Rapid Crack Propagation (RCP) in pressurised pipelines is of particular importancr to th? g a
industry, where the possibility of such a failure must he minimised. Polyethylene (PE) currently dominates
the market for plastic gas pipelines, and as the demands for larger diameters .and higher operating...
1998 Gothenburg : Rapid Crack Propagation
Author(s) : Leevers
The international standardisation of tests for Rapid Crack Propagation (RCP) is approaching
completion, and requirements for product and systems standards x e well established. Yet
some basic issues about RCP remain contentious. In contrast to slow crack growth, there is a
near-absence of service failure data, and in...
1998 Gothenburg : Rapid Extension and Failure of PE Craze Material
Author(s) : Hazra, Leevers
In previous work on the impact behaviour of
pipe grade polyethylene (PE), the 'thermal
decohesion model' was proposed by Leevers
[ l ] to explain the embrittlement of PE under
impact and at low temperatures. One of the
initial assumptions of the model was that the
crack tip craze could be represented by a
1995 Edinburgh : An analytical model of the gas discharge process in the S4
Author(s) : Venizelov, Greenshields, Leevers
An analytical I-D model of the gas discharge
process in the small scale steady State ( ~ 4 )
test for rapid g a c k propagation (RCP) in
thermoplastic pipe has been developed.
Because the gas can exert a powerful crack
driving force, such a model is essential to an
understanding of the test. This model yields
1995 Edinburgh : Fast fracture of plastic water pipes and the measurement of dynamic
Author(s) : Greenshields, Leevers
Previous research has
concluded that rapid crack propagation (RCP)
cannot be sustained in 100% water
pressurised pipe. However, this paper shows
that by reducing the decompression wave
speed in water to below the crack speed, it is
possible t o sustain fast cracks in
thermoplastic pressure pipe.
T h e prediction of R...
1995 Edinburgh : Material, structural and pressurising fluid models for RCP tests on
Author(s) : Leevers, Greenshields, Venizelos, Ivankovic
The development of pipe-grade
materials to resist slow crack growth and
ductile rupture has been spectacularly
successful. It is a measure of this success
that concern with Rapid Crack Propagation
(RCP) has increased to the level evident at
encourage the use of higher...
1995 Edinburgh : The effect of pressurizing fluid on fast fracture in plastic pipes
Author(s) : Greenshiels, Leevers
The failure of a pipe by rapid
crack propagation (RCP) can, by its nature,
be highly desmctive and must be avoided.
Research over the past ten years has
concentrated on gas pressurised pipelines and
has resulted in a greater awareness and
understanding of the problem. Recent
attention has focused on RCP in...