1. No category

Energy Pipelines CRC – Innovation Roadmap – Fracture Control
Match research outcomes with future requirements
Research Activities
Modelling of Decompression
wave velocities
Increase understanding of requirements
RP3-02A: decompression
processes for CH4, CO2, and
other gasses understood
Develop a solution
Implement solution
RP3-02E: effects of pipe wall roughness
and pipe diameter on decompression
wave speed understood
RP7.2.1 / 7.2.2 / 7.2.3: behaviour
of CO2 mixtures understood by
comparing EOS and field testing
Coupled Fracture /
Decompression Models
Increase understanding of gas
decompression for pipe design
RP3-08: model for transient
depressurization of a densephase fluid, incl. single/multiphase flow and heat transfer
RP3-02I: fracture
control model
(EPDECOM) developed
RP3-02F: improved fracture /
decompression models developed
RP3-02C/RP3-02J: 3D FEM simulation
models for CVN tests, DWTT and full scale
pipe fracture developed/ improved
Fracture Simulation
RP6.1-03: relationship found between
absorbed CVN energy and wall
thickness in clean/ dirty linepipe steel
New fracture velocity
model developed
Improve prediction methods for
material requirements and for
fracture arrest
Inform AS2885
update process
RP6.1-04: solution to facilitate DWTT
for smaller diameter pipes developed
Knowledge / IP developed
*Understanding of decompression behaviour of CH4, CO2 (mixtures) and other rich gasses
*Understanding of effects of pipe wall roughness and diameter on decompression wave speed
*Understanding of relationship between absorbed CVN energy and wall thickness in linepipe steel
*Development of a model for transient depressurization of a dense-phase fluid
*Development of 3D FEM simulation models for CVN tests, DWTT and full scale pipe fracture
*Development of FSI model for dynamic ductile fracture in gas pipelines
*Development of improved coupled fracture / decompression models
*Development of solution to facilitate DWTT for smaller diameter pipes
© Energy Pipelines CRC 2015
Developing improved fracturedecompression models
Improve understanding of
fracture propagation processes
RP6.3-06: new FSI model for
dynamic ductile fracture in gas
pipelines developed
RP3-09: Instrumented
charpy machine installed
Needs / Requirements
Utilisation IP
*Release of EPDECOM Fracture control software
*Inform AS2885 update process
*Release of research reports and models
*Education and training of industry
Identify and utilise/commercialise IP
Methods for fracture control in small diameter natural gas and other energy fluid pipelines is a main theme in RP3. The scoping study in this area of research, RP3-02A
‘Modelling of Decompression Wave Velocities’ was designed to ensure that the program of Computational Fluid Dynamic (CFD) modelling and related research work be
as effective as possible. The first research efforts into decompression velocities in gas pipelines were completed with project RP3-02E ‘Decompression Velocities in Rich
Gas Mixtures’. This project involved numerical analysis of decompression processes following pipe ruptures and other transient events. A decompression wave speed
model, EPDECOM, which exhibits higher accuracy than the currently available models such as GASDECOM, is able to predict the effects of pipe diameter and pipe wall
roughness on the decompression wave speed. An improved research version of EPDECOM has been completed (RP3-02I ‘Fracture Control Software’) in which the direct
interaction of gas decompression and fracture propagation at the crack tip is considered (project RP3-02F ‘Coupled Model for Fracture Propagation’). This version of
EPDECOM also builds on the fracture simulation work conducted in projects RP3-02C/RP3-02J and data obtained from full scale fracture test carried out elsewhere in the
world. Project RP3-06 aims to develop accurate numerical models of Fluid-Structure Interaction (FSI) during running ductile fracture as an alternative to full-scale
testing. To ensure the absence of brittle propagation in smaller diameter pipelines, it has been proposed that the DWTT diameter limit in API/ISO standards be extended
to DN300. However, there are issues with obtaining valid DWTT results from high Charpy toughness pipe for small pipe diameters and these are being addressed in
RP6.1-04 ‘Pipe Size Effect in DWTT’ and RP6.1-03 ‘Toughness Review’.
The determination of the material toughness value required for arresting ductile fracture propagation has been historically based on the Battelle Two-Curve Model
(BTCM). However, the current emulations of the BTCM are ambiguous and the approach taken by AS2885.1 to specification of fracture control will be reviewed in the
project RP6.1-03 ‘AS2885.1 Toughness Review’ (RP1/RP3 project).
© Energy Pipelines CRC 2015