Fatigue Design Procedures. Proceedings of the 4th Symposium of the International Committee on Aeronautical Fatigue Held in Munich, 16–18 June 1965

524 Pages·1969·27.13 MB·English

by  E. Gassner

INTERNATIONAL SERIES OF MONOGRAPHS IN
AERONAUTICS AND ASTRONAUTICS
HONORARY ADVISORY BOARD
UNITED KINGDOM UNITED STATES (cont.) GERMANY
A. M. Ballantyne C. Kaplan G. Bock
A. D. Baxter J. Kaplan H. Görtier
W. Cawood J. Keto O. Lutz
J. S. Clarke W. B. Klemperer A. W. Quick
Sir H. Roxbee Gox E. Koteher
Sir W. S. Farren E. H. Krause AUSTRALIA
Sir G. W.H.Gardner Col. N. L. Krisberg L. P. Coombes
W. S. Hemp A. M. Kuethe
S. G, Hooker J. P. Layton BELGIUM
E. T. Jones I. Lees J. Ducarne
W. P. Jones B. Lewis
G. V. Lachmann P. A. Libby ITALY
A. A. Lombard H. W. Liepmann G. Gabrielli
B. P. Mullins J. R. Markham
A. J. Murphy C. B. Millikan CANADA
L. F. Nicholson W. F. Milliken, Jr. J. J. Green
F. W. Page W. C. Nelson H. C. Luttmann
Sir A. G. Pugsley W. H. Pickering D. C. MacPhail
L. H. Sterne R. W. Porter D. L. Mordell
A. D. Young L. E. Root
G. S. Schairer SWEDEN
F. R. Shanley B. K. L. Lundberg
E. R. Sharp
UNITED STATES S. F. Singer POLAND
H. J. Allen C. R. Soderberg F. Misztal
M. Alperin J. Stack
R. L. Bisplinghoff M. Stern FRANCE
W. von Braun H. G. Stever L. Malavard
F. H. Clauser G. P. Sutton M.Roy
M. U. Clauser R. J. Thompson
J. R. Dempsey L. A. Wood SPAIN
W. S. Diehl T. P. Wright Col. A. Pérez-Marin
C. S. Draper M. J. Zucrow
A. Ferri JAPAN
C. C. Furnas I. Tani
C. Gazley, Jr.
E. Haynes HOLLAND
E. H. Heinemann H. J. van der Maas RUSSIA
N. J. Hoff C. Zwikker A. A. Ilyushin
FATIGUE
DESIGN PROCEDURES
Proceedings of the 4th Symposium
of the International Committee on Aeronautical Fatigue
held in Munich, 16-18 June 1965
EDITED BY
E. GASSNER AND W. SCHÜTZ
Laboratorium für Betriebsfestigkeit
Gemeinnütziges Forschimgsinstitut der Fraunhofer-Gesellschaft e. V.
Darmstadt-Eber Stadt, F.R. Germany
$$
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Copyright © 1969
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First edition 1969
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PREFACE
THE Symposium on 'Fatigue Design Procedures', held at Munich, 16-18
June 1965, was organized by the 'International Committee on Aero-
nautical Fatigue' (ICAF) as the fourth ICAF Symposium. It was held
consecutively with a meeting of the Structures and Materials Panel of the
'Advisory Group for Aerospace Research and Development' (AGARD)
of the NATO. Many of the members of the Panel had accepted the in-
vitation from ICAF to attend the Symposium.
As usual, the Symposium also formed part of one of the regular 'ICAF
Conferences', which have been held from 1952 onwards with the purpose
of reaching a fruitful and effective exchange of information on fatigue
problems in aeronautics. Each of the ICAF member countries in turn is
responsible for the organization of one of these conferences, including, if
this is thought to be useful, a symposium on a subject of great current
interest. The German ICAF Centre, the 'Laboratorium für Betriebsfestig-
keit', under the guidance of the German ICAF Delegate, Prof. Dr.-Ing. E.
Gassner, in collaboration with the 'Wissenschaftliche Gesellschaft für
Luft- und Raumfahrt', took care of the very thorough preparations for the
ICAF meeting at Munich. They were assisted in their task by the other
ICAF Centres (Australia, Belgium, France, Italy, The Netherlands,
Sweden, Switzerland, the United Kingdom, and the United States of
America) and by the general secretary of ICAF. Through the courtesy of
AGARD, simultaneous translation was made available at the Symposium.
The subject of the Symposium ranked highly among the interests of
both ICAF and AGARD, and it met with an enthusiastic response when
papers were solicited in the course of 1964. The selection of the papers to be
finally accepted for presentation, the further contacts with the authors,
and many administrative matters required very much work from the
German organizers, for which they fully deserve the sincere thanks of
ICAF. The reactions at and after the Symposium conclusively proved that
their efforts were considered to have led to a very successful and stimu-
lating meeting.
The Symposium was opened with an address by Prof. Dr.-Ing. H. Ebner
and during three days 15 papers were presented to an audience consisting
vii
viii Preface
of 190 fatigue experts from the following countries, who had been invited
to attend; Australia (2), Belgium (3), France (23), Italy (10), The Nether-
lands (18), Sweden (7), Switzerland (12), the United Kingdom (26), the
United States of America (28), and the Federal Republic Germany (61).
This book contains the full text of all papers presented, as well as sum-
maries of the discussions held on them.
The ICAF wishes to record its great appreciation to the German
Government for making the publication of this book possible through
their financial support, and to Professor Gassner and Dr. Schütz for taking
upon themselves the additional task of editing the book.
Amsterdam, November 1965 F. J. PLANTEMA
ICAF Secretary
SESSION CHAIRMEN
W. BARROIS, Service Technique Aéronautique, Paris, France.
J. BRANGER, Eidgenössisches Flugzeugwerk, Emmen, Switzerland.
E. GASSNER, Laboratorium für Betriebsfestigkeit, Darmstadt,
F.R. Germany.
H. F. HARDRATH, National Aeronautics and Space Administration,
Langley Field, Virginia, U.S.A.
E. L. RIPLEY, Royal Aircraft Establishment, Farnborough, U.K.
J. SCHIJVE, National Aerospace Laboratory, Post Emmeloord N.O.P.,
The Netherlands.
GERMAN ORGANIZING COMMITTEE
E. GASSNER W. SCHÜTZ D. SCHÜTZ
Laboratorium für Betriebsfestigkeit, Darmstadt
K. STECKEL
Wissenschaftliche Gesellschaft für Luft- und
Raumfahrt, Köln
ix
SESSION CHAIRMEN
W. BARROIS, Service Technique Aéronautique, Paris, France.
J. BRANGER, Eidgenössisches Flugzeugwerk, Emmen, Switzerland.
E. GASSNER, Laboratorium für Betriebsfestigkeit, Darmstadt,
F.R. Germany.
H. F. HARDRATH, National Aeronautics and Space Administration,
Langley Field, Virginia, U.S.A.
E. L. RIPLEY, Royal Aircraft Establishment, Farnborough, U.K.
J. SCHIJVE, National Aerospace Laboratory, Post Emmeloord N.O.P.,
The Netherlands.
GERMAN ORGANIZING COMMITTEE
E. GASSNER W. SCHÜTZ D. SCHÜTZ
Laboratorium für Betriebsfestigkeit, Darmstadt
K. STECKEL
Wissenschaftliche Gesellschaft für Luft- und
Raumfahrt, Köln
ix
INTRODUCTION
THE fatigue behaviour or fatigue life of a structure is not dependent
exclusively on the type of material used. When dealing with this problem,
it is indispensable that all factors influencing fatigue life are accounted for
and are properly weighted. It is of primary importance to have reliable
information on a representative mission profile, i.e. on the service loads,
their magnitude and frequency. These loads have to be converted into
stresses under due consideration of the dynamic response of the structure.
Material properties (static strength, fatigue strength, crack propagation
characteristics, residual strength, sensitivity to stress corrosion, corrosion,
temperature, etc.) must be considered in relation to details of design and
manufacture. Attention must be paid also to stresses due to assembly.
For the present Symposium, fatigue experts were therefore invited to
submit individual views on the various aspects of the subject outlined
above and on the manner in which these aspects should be dealt with in
order to contribute towards realistic Fatigue Design Procedures. In this
volume, the sequence of the fifteen papers finally selected for presentation
differs slightly from the sequence at the Symposium ; the papers have been
rearranged according to the subject matter.
The Symposium opened with a pilot lecture delivered by Melvin Stone,
Douglas Aircraft Company, giving a detailed survey of the knowledge
invested and the experience gained in the fatigue and fail-safe design of a
new jet transport airplane.
Fatigue strength requirements in the airworthiness regulations, which
have to be complied with in the design of fatigue critical structures, are the
subject of the papers of J. E. Dougherty, Federal Aviation Agency, and of
J. K. Williams, Air Registration Board, referring to civil aviation, and of
H. B. Lowndes and W. B. Miller, U.S. Air Force, referring to military
aviation.
T. L. Coleman, NASA, gives a summary of spectra of normal e.g.
accelerations for a wide range of loading cases, collected by NASA and
NACA for airplanes of various categories and various power systems.
D. James, British Aircraft Corporation, outlines some general aspects
of the selection of suitable materials for the airframe, and he also deals
xi
XII Introduction
with stress corrosion and hydrogen embrittlement. The special problem
of residual static strength, which is of particular importance for fail-safe
structures, is the subject of the paper by W. Barrois, Service Technique
Aéronautique.
W. T. Kirkby and P. R. Edwards, Royal Aircraft Establishment, report
on a special type of random test employing a simple stress spectrum, from
which the fatigue life for a complex spectrum (R.Ae.S. gust spectrum)
can be estimated more accurately than by using Miner's hypothesis.
E. Gassner and W. Schütz, Laboratorium für Betriebsfestigkeit, make use
of notched specimens and of a standard frequency distribution to establish
data, on the basis of programme fatigue tests, for the assessment of allow-
able stresses. The latter take account of the stress concentration factor
and the stress ratio as important parameters. The authors discuss a pro-
cedure, which had already been suggested earlier by Gassner, that allows
programme test results based on the LBF Standard Distribution to be
converted into data representative of the results from a composite gust
spectrum.
S. E. Larsson, Saab Aircraft Company, gives generally applicable rules
for the design of lugs. His analysis incorporates the majority of test results
on this important structural element that have been published so far.
N. F. Harpur, British Aircraft Corporation, and A. J. Troughton,
Hawker Siddeley Aviation, in their joint paper show that full-scale tests in
spite of the considerable expenditure involved are generally worthwhile
also from the viewpoint of economics. E. A. Rossman and W. T. Shuler,
Lockheed-Georgia Company, critically discuss fail-safe and safe-life
design philosophies, the means of implementation and the effect on
structural reliability.
C. A. Patching and J. Y. Mann, Aeronautical Research Laboratories,
deal with the comparison of the fatigue life obtained from simple notched
specimens with that obtained from full-scale wing structures, both in
programme and in random fatigue tests.
In conclusion, H. T. Jensen, Sikorsky Aircraft, and F. Liard, Sud
Aviation, discuss in their respective papers the fatigue problems associated
with the design of rotorcraft components. These problems are different
in many respects from those encountered in fixed wing aircraft design and
consequently make revisions necessary to the relevant regulations and the
methods of fatigue life evaluation.
The editors wish to thank all those who have collaborated in preparing
and organizing the Symposium, and in revising the manuscripts, for their
contribution towards a successful accomplishment of the meeting. If the
subject set up for the Symposium has been met by the limited number of
relevant papers chosen from among the numerous proposals submitted,
Introduction xiii
the editors owe this to the counsel and unremitting assistance of the late
ICAF Secretary Dr. F. J. Plantema and of Prof. Dr. J. Schijve. The editors
also greatly appreciate the co-operation of the authors, which has been
exemplary throughout the preparation of the Symposium and during the
editorial work on the book. Furthermore, they wish to express their
special appreciation to Mrs. Barbara Gökgöl, who collaborated in the
organization of the Symposium and contributed greatly to the post-
Symposium work and to the preparation of the manuscript for this
volume.
Finally, the co-operation of Pergamon Press Ltd. in sparing no effort
to accomplish the publication of this volume is gratefully acknowledged.
Darmstadt, October 1967 E. GASSNER
W. SCHÜTZ