Table Of ContentMethods for the Assessment of
Structural Integrity of Components
and Structures
Methods for the Assessment
of Structural Integrity of
Components and Structures
Edited by
David Lidbury and
Peter Hirsch
MANEY
FOR THE INSTITUTE OF MATERIALS, MINERALS AND MINING
B0778
First Published in 2003for
The Institute of Materials, Minerals and Mining by
Maney Publishing
1Carlton House Terrace
London SWIY 50B
ISBN 1-902653-78-5
© 10M3 2003
All rights reserved
Typeset in the UK by
Keyset Composition, Colchester
Printed and bound in the UK by
Charlesworth Group, Huddersfield
Contents
Contents v
Foreword VB
The Development of Structural Integrity Assessment Methods:
An Overview 1
A. R. Dowling and P. E. J. Flewitt
2 Methods for the Assessment of Structural Integrity of Components
and Structures - Regulator's View - Nuclear Applications 27
A. J. Cadman
3 The Regulator's View: Non-Nuclear Applications 37
Harry Bainbridge
4 SINTAP and R6 Developments: Progress on Codes 49
A. C. Bannister, S. E. Webster and R. A. Ainsworth
5 Fatigue-Based Assessments in Aircraft Structures - Designing and
Retaining Aircraft Structural Integrity 69
P. E. Irving
6 Recent Developments in Methodology for Fracture Mechanics
Assessment 103
D. P. G. Lidbury
v
VI Contents
7 Structural Integrity in Aero Gas Turbine Engines 119
R. S. J. Corran, S. J. Garwood and A. R. M. Walker
8 Methods for the Assessment of the Structural Integrity of
Components and Structures: Civil Structures 141
F. M. Burdekin
9 Applications of Strucural Integrity Assessments for the Offshore
Industry 155
C. S. Wiesner and G. R. Razmjoo
10 Integrity Code Applications in the Transportation Industry 175
Brian Dabell
11 Current Concepts and Future Needs for the Assessment of the
Integrity of Components and Structures 187
John Knott
Foreword
This volume brings together the papers presented at the 8th Symposium organised
by the Technical Advisory Group on Structural Integrity of Nuclear Plant
(TAGSI), held on 25th April 2001 at the TWI Conference Centre at Granta
Park, Great Abington near Cambridge, UK. The subject of this one-day
symposium was "Methods for the Assessment of the Structural Integrity of
Components and Structures. It was attended by over eighty delegates from nuclear
and non-nuclear industries, academia and Government organisations.
The construction, process, power generation, manufacturing and transport
industries all rely on the integrity of appropriate structures and components to
ensure the safe and economic operation of their plant. The object of the
Symposium was to disseminate the various methodologies used in different
industries for the assessment of structural integrity, and to permit comparisons
to be made of the different approaches. There were three sessions. The first
included an overview of the key elements in the assessment process leading to a
safety argument, a repair, a replacement or an operational solution to a structural
integrity problem, and a view by the UK Regulator on the Safety Assessment
Principles in the Nuclear industry. There was another paper by the UK Regulator
on the comparison of the codes used for Engineering Critical Assessments of
conventional pressure plant.
The second session was concerned in part with recent progress worldwide on
fracture assessment codes, including in particular an overview of the SINTAP
procedure, and of the latest revision to the R6 code; another contribution dis-
cussed recent work relevant to the question of transferability of fracture toughness
parameters between test specimens and structure. A paper on fatigue-based struc-
tural assessments for aircraft structures highlighted the challenges for maintenance
of structural integrity brought about by the use of new materials and fabrication
processes.
The third session consisted of papers by users of structural integrity codes in
applications in various industries. A paper on the code requirements for aero-gas
turbines described the approaches used for engine discs, blades and thin shell
components such as pressure casings and combustors. The application of codes
in various civil engineering structures was illustrated by examples which included
inter alia the spindle of the London Eye, fracture requirements for steel bridges
and assessment of defects in an airport roof structure. A paper on the application
VII
viii Foreword
of Engineering Critical Assessment of off-shore structures included examples of
mobile drilling units and pipelines. The contribution of the application ofintegrity
codes to pressurised components in the process industry described the different
codes utilised, and emphasised the conservative approach used in component
design. The session ended with a general summary by Professor Knott of future
needs for the assessment of the integrity of components and structures. The.
Symposium was remarkable for the great variety of structural integrity issues
addressed.
P.B. Hirsch
D.P.G. Lidbury
CHAPTER 1
The Development of Structural Integrity
Assessment Methods: An Overview
A. R. Dowling and P. E. J. Flewitt
BNFL Magnox Generation, Berkeley Centre, Berkeley, Gloucester GL13 9PB, UK
ABSTRACT
Understanding the integrity of critical structures has been a driving force for the
development of engineering analysis methods since Galileo, in the seventeenth
century, investigated the resistance of a beam subject to bending loads.
Construction, process, power generation, manufacturing and transport industries
need to be able to assure the safe and economic operation of their plant by relying
on the integrity of appropriate structures and components. The design engineer
assists in the creation of a structure or component by using analytical tools and
supporting data most appropriate for the application. Bycomparison, the operator
of the plant has to ensure that, throughout the service life, it is secure against the
design intent. Both offer challenges with respect to the structural integrity diagnosis
and assessment which forms an essential input to providing the necessary assurance
of safe and reliable operation. In general, failure of structures or components can
have profound commercial and financial implications. However, there are areas
where failures are completely unacceptable due to the impact on the environment
and society. Those industries where this isparticularly relevant are nuclear, chemical
and transportation. To specify and formulate the overall strategy for safe, reliable
and economic operation requires acomprehensive understanding ofthe capability of
the plant to meet the required duty based upon a structural integrity assessment.
In this overview, we consider what assessment methods designers and assessors
require, the tools available and the needs of specific industries. Recent and future
developments are discussed briefly.
INTRODUCTION
Understanding the integrity of critical structures has been a driving force for the
development of engineering analysis methods since Galileo, in the seventeenth
century, investigated the resistance of a beam subject to bending loads.'
Construction, process, power generation, manufacturing and transport industries
need to be able to assure the safe and economic operation of their plant by relying
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