Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Lined Pipe Testing and Finite Element Modelling for Reel-Lay Application
Minh Le, Mamadou Ahmed-Kogri, Richard Stableford, Eric Giry
Offshore Subsea Engineering, Saipem SA
Montigny Le Bretonneux, France

the liner, known as “wrinkling”, when installed by reel-laying (Vasilikisand Karamanos, 2012), or under repeated large bending (Bartolini et al.,2017). Several works were performed to address specifically theconditions that may trigger a wrinkle, from a numerical perspective(previous references), or combining experimental and numerical studies(Toguyeni and Banse, 2012). Some proposed criteria to anticipate thesituation where liner wrinkling may occur e.g.: JIP for lined and clad
pipelines (2018), Tkaczyk et al. (2020), Le et al; (2021). Test campaigns
were reported in recent years with dedicated instrumentation based onlaser scanning to quantify the liner response and calibrate finite element
model, e.g. Focke et al., (2007). High resolution measurements generatea large amount of data that requires a specific processing in order to getvaluable interpretation such as the one described by Harrison et al.
(2016). Some test programmes focused on local feature that could initiate
a wrinkle such as a weld (Jones et al., 2021) or a liner imperfection(Pepin et al., 2019). However, to the authors knowledge, there is no MLP
bending test involving an anomaly that specifically triggers a wrinkle
that is measured with high resolution instrumentation and simulatedthrough Finite Element Analysis. This paper proposes a comparison
between experimental and numerical experience for such a case.
As part of an extensive test programme to validate finite element models
for reel-laying application (Fig. 1), various full-scale reeling trial test
strings have been fabricated for MLP reeling trials. Some have plain
lined bodies, some incorporating deliberate delaminations between theliner and backing steel and some with girth welds concentrating on theperformance of the liner transition (triple point).

ABSTRACTIn this paper a numerical model is proposed for Mechanically Lined pipe
(MLP). LASER based scanning techniques were used to capture local
straining of the liner and Digital Imaging Correlation (DIC) of thebacking steel outer during simulated reeling trials. This included
wrinkling generated by an unexpected anomaly near the transition areaof one test string. Data was collected pre-reeling, during reeling andpost-reeling. The numerical model developed to simulate the bending
trial corresponds well with test data, proving the method useful forfurther MLP modelling studies.
KEY WORDS
Mechanically Lined Pipe; Abaqus; Python; LASER scanning;
Eigenvalue Analysis, Liner Wrinkling.
NOMENCLATURE

CRACorrosion Resistant Alloy

DIC

Digital Imaging Correlation

DNVDet Norse Veritas

ERW

Electrical Resistance Welding

FE (A), (M)

Finite Element (Analysis), (Modelling)ID

Inner Diameter

MLP

Mechanically Lined Pipe

OD

Outer Diameter of pipe

SMLS

Seamless (pipes)

SVD

Singular Value Decomposition

WT

Wall Thickness

2-D

2 Dimensional

3-D

3 Dimensional
Fig. 1. Saipem Constellation reel-lay vessel

INTRODUCTION

6 pressurised reeling simulation trials were conducted on test strings withgirth welds. A 7th test string was constructed to test at ambient pressureduring reeling and installation. During post-assembly (pre-reeling)inspections, this test string was found to have an unexpected “anomaly”
back from one triple point, further into the lined section of the test string.
This resulted in a test string which coincidentally had one representative

Mechanically lined pipe (MLP) is a cost-effective solution to transmit
corrosive hydrocarbon fluids. A carbon steel host pipe shelters a thin
tubing layer made of Corrosion Resistant Alloy (CRA). The thin tubing
is inserted and expanded to fit the inner surface of the host pipe. A
specific failure mode can occur based on delamination and collapse of1713