Measurement of Residual and Applied Stress Using Neutron Diffraction

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Series E: Applied Sciences - Vol. 216

Measurement of Residual and Applied Stress Using Neutron Diffraction edited by

Michael T. Hutchings National Non-Destructive Testing Centre, AEA Technology, Harwell Laboratory Didcot, Oxfordshire, U.K.

and

Aaron D. Krawitz Department of Mechanical and Aerospace Engineering and Research Reactor Center (MURR), University of Missouri, Columbia, Missouri, U.S.A.

Springer Science+Business Media, B.V.

Proceedings of the NATO Advanced Research Workshop on Measurement of Residual and Applied Stress Using Neutron Diftraction Oxford, United Kingdom March 18-22, 1991

Library of Congress Cataloging-in-Publication Data

Measurement of residual and applied stress uslng neutron dlffraction I edited by Michael T. Hutchings and Aaron D. Krawitz.

p. cm. -- (NATO ASI series. Series E. Applied sciences ; no. 216)

Includes bibliographical references and index.

1. Neutron radiography--Congresses. 2. Residual stresses~ -Measurement--Congresses. 1. Hutchings. Michael T. II. Krawitz. Aaron D. III. Series. TA417.25.M43 1992 620.1' 124--dc20

ISBN 978-94-010-5242-9

Printed on acid-free paper

AII Rights Reserved © 1992 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 1992 Softcover reprint of the hardcover 1 st edition 1992

92-16842

No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photo­copying, recording or by any information storage and retrieval system, without written permission from the copyright owner.

ISBN 978-94-010-5242-9 ISBN 978-94-011-2797-4 (eBook)DOI 10.1007/978-94-011-2797-4

TABLE OF CONTENTS

PREFACE AND ACKNOWLEDGEMENTS

WORKSHOPPHOTOQRAPH

IDENTIFICATION IN PHOTOGRAPH

LIST OF PARTICIPANTS

WORKSHOP PAPERS

1. OVERVIEW

'Neutron Diffraction Measurement of Residual Stress Fields: Overview and Points for Discussion'

M T HUTCHINGS

2. BACKGROUND

xi

xiv

xv

xvii

3

'Role of Neutron Diffraction in Engineering StressAnalysis' 21 GA WEBSTER

'Applications of X-ray Residual Stress Measurements in Industrial R&D' 37 MRJAMES

'The Theory of Stress/Strain Analysis with Diffraction' 51 ICNOYAN

The Calculation of Residual Stress' 67 SSJOSTROM

'Comparison Between Finite Element Calculations and Neutron Diffraction Measurements of Residual Stress in a Diametrically Compressed Ring' 93

T M HOLDEN, R R HOSBONS, S R MacEWEN, E C FLOWER, M A BOURKE and J A GOLDSTONE

vi

3. ASPECTS OF FUNDAMENTAL PRINCIPLES

'Macrostresses, Microstresses and Stress Tensors' 115 L PINTSCHOVIUS

'Separation of Microstresses and Macrostresses' 131 RAWINHOLTZ

'The Effects of Crystalline Anisotropy on the Elastic Response of Materials' 147 C G WINDSOR and T IZUY AMA

'Investigation of Large Grained Samples - Principles' 159 WREIMERS

'The Plastic Regime, Including Anisotropy Effects' 171 T LEFFERS and T LORENTZEN

'Grain Interaction Stresses' 189 L PINTSCHOVIUS

'Relaxation' 205 PJWITHERS

'Interpretation of Residual Stress Measurements: Summary of Discussion 223 Session'

T M HOLDEN and A W BOWEN

4. ASPECTS OF EXPERIMENTAL MEASUREMENT

'Spatial Resolution and Strain Scanning' 235 PJWEBSTER

'Strain Tensor Measurements by Neutron Diffraction' 253 T LORENTZEN and T LEFFERS

'Investigations of Large Grained Samples - Examples' 263 W REIMERS, H -A CROSTACK, M WROBLE and G ECKOLD

'The Stress-Free Reference Sample: Alloy Composition Information from Neutron Capture' 277

H G PRIESMEYER

'The Precision of Peak. Position Determination in Diffraction Measurements of Stress'

C G WINDSOR (Paper arising from discussions at Workshop) 285

vii

'Errors in Analysis' 297 A J ALLEN ( Abstract only)

5. INSTRUMENTATION Sa INSTRUMENTATION: STEADY STATE REACTOR

'Optimised Geometry for a Stress Measurement Two-Axis Diffractometer at a Reactor' 301

F M A MARGA<;A

'Implementation and Application of a PSD Set-up for Neutron Diffraction Strain Measurements' 313

T LORENTZEN, T LEFFERS and D JUUL JENSEN

'Reverse Time-of-Flight Fourier Technique for Strain Measurements' 329 H G PRIESMEYER

'The Alignment of Instrumentation and the Positioning of Specimens for Stress Measurements by Means of Neutron Diffraction'+ 335

PC BRAND

'Proposal for a Neutron Strain Measurement Apparatus'+ 347 M KOCSIS and J KULDA

'Microbeam Techniques in Diffraction: A Theoretical Treatment' 353 I C NOY AN ( Abstract only)

'Summary of the Panel Discussion on Instrumentation at Steady State Sources' 355 T LORENTZEN and P C BRAND

5b INSTRUMENTATION: PULSED NEUTRON SOURCE

'Residual and Applied Stress Measurements at lPNS' 363 J W RICHARDSON, JR.

'Residual Stress Measurement using the Pulsed Neutron Source at LANSCE' 369 M A M BOURKE, J A GOLDSTONE and T M HOLDEN

'Stress Measurement: Experience at ISIS' 383 SHULL, W I F DAVID and M W JOHNSON

'Transmission Bragg-Edge Measurements' 389 H G PRIESMEYER

viii

'MACS, The Manipulation and Collimation System on the NPD at LANSCE'+ 395 M A M BOURKE, J A GOLDSTONE AND K J LOVELL.

'The Design of a Pulsed Source Instrument: Summary of Discussion Session' 401 SHULL

6, COMPOSI1ES

'Stress Measurements in Composites using Neutron Diffraction' 405 AD KRAWITZ

'Theory and Modelling of Composites' 421 PJWITHERS

'Application of Neutron Diffraction Time-of-Flight Measurements to the Study of Strain in Composites' 439

D S KUPPERMAN, S MAJUMDAR, J P SINGH and A SAIGAL ( Presented by J W RICHARDSON JR.)

'Deformation Analysis in Mixed Composites' 451 U SEL V ADURAI-LASSL, H -A CROSTACK, W REIMERS, T VOGT

andGECKOLD

'Surface and Near-Surface Analysis of Residual Stresses in Aluminium and Titanium Alloys - Examples of the Case for X-ray Diffraction' 461

PHOLDWAY and A WBOWEN

'Residual Stresses in Brazed Ceramic-Metal Compounds' 473 L PINTSCHOVIUS, N PYKA, R KUSSMAUL, D MUNZ, B EIGENMANN

and B SCHOL 1ES ( Presented by W REIMERS)

7, MEASUREMENTS ON BULK COMPONENTS

'Residual Stress Distribution in Cracked Autofrettaged Tubing' 481 M A M BOURKE, H J MacGILLIVRAY, G A WEBS1ER and P J WEBS1ER

'Measurement of Stresses in Metal Adhesive Joints' 493 A LODINI, J LI, M PERRIN, F DUNS1ET1ER and L RIMLINGER

'Residual Stress Measurements in Armament-Related Components' 503 H J PRASK and C S CHOI

'Problems with Railway Rails'+ 517 P J WEBS1ER, X WANG and G MILLS

ix

'Neutron Measurements of Residual Strain in some Technological Materials and Components'+ 525

G ALBERTINI, M CERETTI, R COPPOLA, A LODINI, M PERRIN and F RUSTICHELLI

'Development of the Neutron Diffraction Technique for the Determination of Near Surface Residual Stresses in Critical Gas Turbine Components'+ 535

AN EZEILO, P S WEBSTER, G A WEBSTER and P J WEBSTER

'Residual Stresses at Cold Expanded Fastener Holes'+ 545 L EDWARDS AND A T OZDEMIR

'Neutron and X-ray Diffraction Residual Stress Measurements on Power Generator Turbine Blades: Comparison with Finite Element Analysis' 555

M KIJEK, T R FINLAYSON and R L DAVIS (Abstract only)

8. COMPARISON OF NEUTRONS WITH X-RAYS AND OTHER STRESS PROBES

INDEX

'Calibration of Portable NDE Techniques for Residual Stress Measurement' 559 AJ ALLEN

'Triaxial Analysis of Residual Stress Fields in Metallic Plates'+ 573 L CASTEX and J BARRALIS ( Abstract only)

'Pitfalls of Layer Removal Techniques in X-ray Residual Stress Measurements' 575 M JAMES (Abstract only)

'Neutrons Versus X-rays' L PINTSCHOVIUS

(Authors, Subjects)

577

581

~ Speaker is Underlined in multi-author papers.

+denotes Poster Paper.

PREFACE

The accurate, absolute, and non-destructive measurement of residual stress fields within

metallic, ceramic, and composite engineering components has been one of the major problems

facing engineers for many years, and so the extension of X-ray methods to the use of neutrons

represents a major advance. The technique utilizes the unique penetrating power of the neutron

into most engineering materials, combined with the sensitivity of diffraction, to measure the

separation of lattice planes within grains of polycrystalline engineering materials, thus providing

an internal strain gauge. The strain is then converted to stress using calibrated elastic constants.

It was just over ten years ago that the initial neutron diffraction measurements of residual stress

were carried out, and during the ensuing decade measurements have commenced at most steady

state reactors and pulsed sources around the world. So swift has been the development of the

field that, in addition to fundamental scientific studies, commercial measurements have been

made on industrial components for several years now. The use of neutrons is ideally suited to

the determination of triaxial macrostress tensors, macrostress gradients, and microstresses in

composites and multiphase alloys as well as deformed, plastically anisotropic metals and alloys.

To date, it has been used to investigate welded and heat-treated industrial components, to

characterize composites, to study the response of material under applied loads, to calibrate more

portable methods such as ultrasonics, and to verify computer modelling calculations of residual

and applied stress.

The small but active neutron stress measurement community convened in Oxford from

March 18-22, 1991, for the first full week's meeting dedicated to discussing the problems,

progress, and future potential of the method. Most of the current experts in the technique were

able to participate, as well as representatives of related disciplines. This volume is the

proceedings of that meeting, and as such represents a definitive statement of the current status of

the field. The papers contained herein, all of which have been professionally refereed, represent

a comprehensive, largely self-contained, source of information on the use of neutrons for

residual stress analysis. Although it is probably best to let the contributors speak for themselves

through these papers, a brief outline of the Workshop, and thus the status of the field today, may

prove useful to readers of this volume.

The scope of the Workshop programme can be summarized as follows. An overview of

the method was first presented, followed by background presentations on the industrial need for

such measurements, examples of industrial X-ray applications, and various analytical

xi

xii

perspectives. Fundamentals were then extensively addressed, including the extraction of stress

tensors and the errors involved, separation of macro- and microstresses, stress-free reference

standards, problems caused by anisotropy, large grains and texture, plasticity, and grain

interaction and relaxation issues. In the consideration of these points the interaction of those

measuring stress with experts in materials science and mechanical metallurgy is proving of

increasing value to all concerned. Instrumentation was a major theme and included discussion

of optimization of instruments, the use of position-sensitive detectors and soller collimators,

microbeam methods, instrument and sample alignment methodology, Fourier techniques, peak

fitting and analysis errors, and resolution in both strain and gauge volume sampled. The use of

pulsed sources was explored and their virtues and limitations relative to steady state sources was

a central theme. The study of composites and the measurement of microstresses was described

and examples were shown. Examples of applications and problems in the measurement of bulk

components were presented. Interesting results on stress gradients within one millimetre of a

surface led to considerable debate about how close to a free surface one can measure, and

whether or not probe volumes can be allowed to partially leave a sample. In contrast to these

points of detail in strain measurement, an invited evening speaker recounted his experience

using conventional strain gauges to deal with practical in situ problems occurring in industry.

In all of this work the value of analytical, theoretical, and numerical support for diffraction

measurements was apparent, as was, conversely, the requirement for validation of numerical and

analytical models of stress fields. The concluding presentations dealt with a comparison of the

neutron method with other stress probes. Three discussion sessions on topics of interest were

held during the Workshop, and brief reports of their conclusions are included in this volume.

Participants had an opportunity to make an afternoon visit to the ISIS spallation neutron source

at the nearby Rutherford Appleton Laboratory.

Although these remarks hopefully capture the primary focus of the meeting, other points

are worth noting. Though it was the charge of the Workshop to deal with problems in the field,

and many of the papers therefore dwell on them, it should be emphasised that this volume is

basically a positive statement of the considerable progress and success of the method. It was

intentional that some of the participants had used only X-rays for the measurement of stress,

since the neutron method is an outgrowth of decades of successful X-ray stress methods which

will remain the primary diffraction tool for near-surface residual stress problems because they

are more appropriate, cheaper and more readily accessible. A final point is that although the

need for answers to practical industrial problems will probably be the main impetus to work in

xiii

the field, the use of the method to give new unique infonnation on the more fundamental

aspects will undoubtedly continue to develop and, in return, to widen the application.

Finally, the Workshop participants expressed a desire to pursue a number of actions. It

was agreed in principle that round robin testing of a standard specimen would be useful, and

steps were taken to select an appropriate sample. It was also agreed to begin considering an

ASTM standard for neutron stress measurements and, as a first step, the recently written X-ray

procedure will be reviewed. Lastly, a search for a regular organ for communication within the

field was initiated, probably through the new journal Neutron News.

ACKNOWLEDGEMENTS

The NATO Advanced Research Workshop Programme is gratefully acknowledged for

financial support, under grant No ARW-900S14, which made this most timely and successful

meeting possible. We would also like to acknowledge the National NDT Centre of AEA

Technology for their help with the organisation, and the staff of Jesus College, Oxford, for their

hospitality and impeccable logistic support. We thank T Leffers and L Pintschovius for joining

us on the Organising Committee of the Workshop.

M T Hutchings, Harwell Laboratory

A D Krawitz, University of Missouri

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Director: M T HUTCHINGS,

Committee: ADKRAwITZ,

L PlNTSCHOVIUS,

TLEFFERS,

USA: MAMBoURKE,

J A GOLDSTONE,

MRJAMES,

ICNOYAN,

HJPRASK, J W RICHARDSON, JR.,

RA WINHOLTZ,

Canada: TMHoLDEN,

U.K.: AJALLEN,

AWBoWEN, LEnwARDS,

ANEzEILo,

PHOLDWAY, SHULL,

MWJOHNSON,

GMILLS,

LIST OF P ARTICIP ANTS

NNDTC, AEA Technology, B521.l, Harwell Laboratory, Didcot, OX11 ORA,UK.

(Deputy Director) Dept. of Mechanical and Aerospace Engineering and Research Reactor Center (MURR), Univ. of Missouri, Columbia, MO 65211, USA.

KFK, Institutfur Nukleare Festkorperphysic, Postfach 3640, D-7500 Karlsruhe, Germany.

Materials Dept., Riso National Laboratory, P.O. Box 49, DK-4000 Roskilde, Denmark.

MS H805, P-LANSCE, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.

MS H805, P-LANSCE, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.

Rockwell International Science Center, 1049 Camino Dos Rios, P.O.Box 1085, Thousand Oaks, CA 91358, USA.

IBM Research, T G Watson Research Center, P.O.Box 218, Yorktown Heights, NY 10598, USA.

Bldg. 235, NIST, Gaithersburg, MD 20899, USA. IPNS Div., Bldg.360, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne,IL 60439, USA.

Dept. of Materials Science and Engineering, Northwestern Univ., Evanston, IL 60208, USA. (Present address: Dept. of Mechanical and Aerospace Engineering and Research Reactor Center (MURR), Univ. of Missouri, Columbia, MO 65211, USA.)

Neutron and Solid State Physics Branch, Atomic Energy of Canada Ltd., Research Company, Chalk River Nuclear Laboratories, Chalk River, Ontario, Canada KOJ lJO.

NNDTC, AEA Technology, B521.l, Harwell Laboratory, Didcot,OX11 ORA, UK. (Present address: Bldg. 223, NIST, Gaithersburg, MD 20899, USA.) .

Materials Structures Dept., RAE Farnborough, Hants. GU14 6TD, UK. Fracture Research Group, Faculty of Technology, The Open University, Milton Keynes, MK7 6AA, UK.

Dept. Mechanical Engineering, Imperial College, Exhibition Road, London SW72BX,UK.

Materials Structures Dept., RAE Farnborough, Hants. GU14 6TD, UK ISIS Facility, Bldg. R3, Rutherford Appleton Laboratory, Chilton, Didcot,

OX11 OQX, UK. ISIS Facility, Bldg. R3, Rutherford AppletonLaboratory, Chilton, Didcot

OX11 OQX, UK. Dept. of Civil Engineering, Univ. of Salford, Salford, M5 4WT, UK.

xvii

xviii

EPROCfER, X WANG,

GA WEBSTER,

P JWEBS1ER,

PSWEBSTER,

CGWINDSOR,

P J WITIffiRS,

France: MKocsIS,

A LODINI,

EPLUYETIE,

Netherlands: PC BRAND,

Germany: H G PRIESMEYER,

WREIMERS,

Denmark: T LORENTZEN,

Italy: F RUSTICHELLI,

Greece: S M SKOLIANOS,

Portugal: F M A MARGAt;:A,

Sweden: S SJOSlROM,

Australia: MKIJEK,

66, Kenilworth Road, Leamington Spa, Warwickshire, CV326JX, UK. Dept. of Civil Engineering, Univ. of Salford, Salford, M5 4WT, UK. Dept. Mechanical Engineering, Imperial College, Exhibition Road, London

SW72BX, UK. Dept. of Civil Engineering, Univ. of Salford, Salford, M54WT, UK. Rolls Royce pic., PO Box31, Derby, DE2 8B!, UK. NNDTC, AEA Technology, B521.1, Harwell Laboratory, Didcot,OXll ORA,UK.

Dept. of Materials Science and Metallurgy, Univ. of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, UK.

Institut Laue Langevin, BP 156 Centre de Tri, 38042 Grenoble Cedex, France.

Ecole Superieure d'Ingenieurs en Emballage et Conditionnement, 51100 Reims Cedex, France.

Laboratoire MecaSurf, ENSAM, 2 Cours des Arts et Metiers, 13617 Aix-en­Province Cedex, France.

ECN, PO Box 1, 1755 ZG Petten, The Netherlands. (Present address: Reactor Radiation Division, NIST, Gaithersburg, MD 20899, USA.)

Institutfur Reine und Kernphysik Universitat Kiel, c/o GKSS Research Center, Box 1160, D-2054 Geesthacht, Germany.

Hahn-Meitner-Institut Berlin GmbH, Group N5, Glienicker Str.IOO, W-I000 Berlin 39, Germany.

Materials Dept., Riso National Laboratory, P.O. Box 49, DK-4000 Roskilde, Denmark.

Instituto di Fisica Medici, Facolta di Medicina e Chirurgia, Universita degli Studi, Via Ranieri- Monte d'Ago, 60131 Ancona, Italy.

Dept. of Mechanical Engineering, Laboratory of Physical Metallurgy, Aristotle University ofThessaloniki, POBox 1552, 540 06 Thessaloniki, Greece.

Dept. Fisica, ICEN, ENI0, 2685 Sacavem, Portugal.

Dept. of Mechanical Engineering, Linkoping University, S-58183 Linkoping, Sweden.

Dept. of Physics, Monash University, Clayton, Victoria 3168, Australia.