Table Of ContentProbabilistic Methods in the
Mechanics of Solids and Structures
The Weibull Symposium
International Union of Theoretical
and Applied Mechanics
Probabilistic Methods
in the Mechanics
of Solids and Structures
Symposium Stockholm, Sweden
June 19-21,1984
To the Memory of Waloddi Weibull
Editors
S. Eggwertz and N. C. Lind
With 149 Figures
Springer-Verlag
Berlin Heidelberg New York Tokyo
Prof. Sigge Eggwertz
The Aeronautical Research Institute of Sweden
Box 11021
S -16111 Bromma - Sweden
Prof. Niels C. Lind
Department of Civil Engineering
University of Waterloo
Waterloo, Ontario N 2L 3G1 - Canada
ISBN-13:978-3-642-82421-0 e-ISBN-13:978-3-642-82419-7
001: 10.1007/978-3-642-82419-7
Library of Congress Cataloging in Publication Data.
Main entry under title:
Probabilistic methods in the mechanics of solids and structures.
At head of title: International Union of Theoretical and Applied Mechanics.
Papers presented at the IUTAM Symposium on
Probabilistic Method in the Mechanics of Solids and Structures,
held in Stockholm, Sweden, June 19-21, 1984.
1. Mechanics, Applied--Congresses.
2. Probabilities--Congresses.
3. Weibull, Waloddi 1887-1979--Congresses.
I. Eggwertz, S. (Sigge).
II. Lind, N. C. (Niels Christian).
III. Weibull, Waloddi, 1887-1979.
IV. International Union of Theoretical and Applied Mechanics.
V. IUTAM Symposium on Probabilistic Methods in the Mechanics of Solids
and Structures (1984: Stockholm, Sweden).
TA349.P74 1984 620.1'05 85-2569
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© Springer-Verlag, Berlin, Heidelberg 1985
Soltcover reprint 01 the hardCover 1st edititon 1985
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2061/30205432 1 0
Scientific Committee
V.V. Bolotin, USSR
O. Buxbaum, Germany'FRG
S. Eggwertz, Sweden, Co-chairman
R.A.Heller, U.S.A.
J. Hult, Sweden
N.C. Lind, Canada, Co-chairman
A.O. Payne, Australia
A. Pugsley, UK
R. Talreja, Denmark
T. Yokobori, Japan
Honorary Chairman
Folke Odqvist, Professor Emeritus, Royal Institute of
Technology KTH, Stockholm, deceased on May 7, 1984
Local Organizing Committee
S.O. Olin, Director General of FFA
B. Bergman, Linkoping Institute of Technology
A. Blom, FFA
S. Eggwertz, FFA
Ella Forsberg, FFA,
L. Jarfall, SAAB-SCANIA AB, Aerospace Division,
F. Nilsson, Swedish Nuclear Power Inspectorate
B. Palmberg, FFA
Sponsors
International Union of Theoretical and Applied Mechanics IUTAM
Aeronautical Research Institute of Sweden FFA
Alfa-Laval AB
ASEA AB
Atlas-Copco AB
AB Bofors
Industry Group JAS:
SAAB-SCANIA AB, Aerospace Division
Ericsson Radio Systems AB
FFV
Volvo Flygmotor AB
Philips Elektronikindustrier AB
Sandvik AB
Scandinavian Airlines System SAS
AB SKF
STAL-LAVAL Turbin AB
Preface
The IUTAM Symposium on Probabilistic Methods in the Mechanics
of Solids and Structures, dedicated to the memory of Waloddi
Weibull, was held in Stockholm, Sweden, June 19-21, 1984, on
the initiative of the Swedish National Committee for Mech
anics and the Aeronautical Research Institute of Sweden,
FFA.
The purpose of the symposium was to bring together mathema
ticians that develop the theory of stochastic processes and
methods for reliability analysis, with engineers that apply
these theories and methods to model loads, strengths and
structures for the advancement of structural safety. Waloddi
Weibull was a pioneer in this field with his many publi
cations from the thirties until his death in 1979. He also
took an active part in the formation of the International
Union of Theoretical and Applied Mechanics during the
forties, and subsequently initiated foundation of the Swedish
National Committee for Mechanics, through which Sweden joined
IUTAM as a member.
116 participants from 21 countries attended the symposium,
and 55 invited papers were presented in 7 scientific sessions.
The first session including 9 contributions was devoted to
extreme value theory with special attention to the Weibull
distribution. One further mathematical session treated re
liability analysis. Probabilistic failure models were dis
cussed both for brittle and ductile materials of various
kinds also including composites. Stochastic modelling of
fatigue crack growth appears to be in rapid progress and was
the subject of a long series of lectures. Other papers were
concerned with the safety of nuclear structures containing
cracks and other defects. An extensive session described the
VIII
structural linear and nonlinear response to random loading,
such as wind turbulence and earthquake spectra. Although the
invitations to the symposium indicated loadings as a main
subject, there was no contribution on the acquisition of
random loads. The last session dealt with structures, es
pecially in aircraft and buildings, including design philo
sophy, codes and certification. At the end of this session
the chairman presented a resolution originating from the
Australian member of the Scientific Committee, meant to be
sent to the International Civil Aviation Organization, re
commending a reliability based approach to fatigue substan
tiation.
The arrangement of the symposium was entrusted to FFA
already in 1981 by the Bureau of IUTAM, which simultaneously
appointed a Scientific Committee of eight members besides the
co-chairmen. These members have served the Committee with
great efficiency, particularly in the important task of
advising on policy and attracting qualified contributors.
A local Organizing Committee was formed at FFA, including
three outside members, selected as experts in various fields
of the symposium. Their generous help has been invaluable.
Several members of the staff of FFA have also made devoted
efforts to advance the symposium inside and outside the
Organizing Committee.
The Honorary Chairman, Folke Odqvist, an old friend and col
league of Waloddi Weibull, played a great part in encouraging
FFA to undertake the arrangement of the Weibull Symposium -
which was only natural, considering the long and prosperous
cooperation between Professor Weibull and FFA. We deeply
regret the death of Professor Odqvist shortly before the
opening of the symposium.
We would like to express our gratitude to the IUTAM Bureau
for the allocation of financial support to participants.
Finally, we wish to give sincere thanks to the thirteen
Swedish companies listed below for their generous financial
support facilitating the efforts to make the symposium a
pleasant event open to qualified scientists from all
countries.
Bromma and Waterloo, October 1984
Sigge Eggwertz Niels C. Lind
Co-chairmen of the Scientific Committee
W. Weibull 1887-1979
photo: Sam C. Saunders, Pullman WA, USA
The Weibull Distribution did not Apply to Its
Founder
Robert A. Heller Blacksburg, VA, USA
Though it is an honor to have been asked by the Chair to talk about
Professor Weibull, I am saddened that my substitution is occasioned by the
untimely passing of another great engineer, Professor Folke Odqvist, who
was to give us his impressions of his old friend and colleague.
The information I have gathered about Professor Weibull comes from several
sources; from his friends: Professor Odqvist, Walter Trapp of the U.S Air
Force, Professor Sigge Eggwertz of FFA, from his family: Mrs. Ibbi
Weibull, his wife, Mr. Goran Weibull, his son, and my own personal recol
lections.
Waloddi Weibull was born on June 18, 1887. This Symposium started on his
97th birthday. His family originally came from Schleswig-Holstein, at
that time (in the seventeenth century) closely connected with Denmark.
There were a number of famous scientists and historians in the family.
His own career as an engineer and scientist is certainly an unusual one.
He became a midshipman in the Royal Swedish Coast Guard in 1904 and was
promoted to sublieutenant in 1907, to Captain in 1916 and to Major in
1940. By then he had finished the military schools and simultaneously
taken courses at the Royal Institute of Technology and at Stockholm
University, finally graduating as Fil.Lic. in 1924. Weibull left active
military service in 1917 and acted in German and Swedish industries as an
inventor (ball bearings, electric hammers) and as a consulting engineer.
He published his first scientific paper on the propagation of explosive
wave in 1914. He took part in expeditions to the Mediterranean, to the
Carribean, and to the Atlantic and Pacific Oceans on the research ship
"Albatross" where he used his newly developed technique of explosive
charges to determine the type of ocean bottom sediments and their thick
ness. The same method is used today in offshore oil explorations.
Weibull became a full professor at the Royal Institute of Technology in
1924, and was awarded the degree Ph.D.h.c. at the University of Uppsala in
XIV
1932. In 1941 a donation from a Swedish arms factory (A. B. Bofors) gave
him a personal research professorship in Technical Physics at the Royal
Institute of Technology, Stockholm.
Professor Weibull's ideas about the statistical distributions of material
strength came to the attention of engineers in the late 1930's with the
publications of two important papers: "Investigations into strength pro
perties of brittle materials" and "The phenomenon of rupture in solids".
His techniques later found wide application in many fields. With great
physical insight he proposed the probability distribution which bears his
name. Now, in the literature on reliability, statistics, fatigue, frac
ture and many other fields, one finds reference to the "Wei bull Distribu
tion", and the statistical methods Weibull proposed are in everyday use.
Subsequently, Dr. Weibull extended his studies to many aspects of fatigue,
fracture and the analysis of probability distributions.
In 1953 he retired from the Royal Institute of Technology and became a
professor emeritus. For most people retirement is the end of a profes
sional career, but not for Weibull. His activities just started. He
became a consultant to the Fatigue Branch of the U.S. Air Force Materials
Laboratory, then under the direction of Mr. Walter Trapp. For 14 years he
conducted research and wrote many papers and technical reports which pro
vide valuable information and data on material properties and on the
analysis of probability distributions and other related topics. This and
other work is summarized in a book. co-authored with his son Goran and
published by the Swedish National Defense Research Institute. Professor
Weibull continued to be active as a consultant. He conducted work on tur
bine fatigue and studied new methods of estimating the parameters of the
Weibull Distribution. His work on the planning and interpretation of
fatigue data is monumental and resulted in his book "Fatigue Testing and
Analysis of Results" in 1961.
In 1963. at the invitation of the late Professor Alfred Freudenthal, he
became a Visiting Professor at Columbia University's Institute for the
Study of Fatigue and Reliability. Many of us at this Symposuim have been
associated with the Institute at that time and got to know Dr. Weibull
personally. Hal Liebowitz was one of our sponsors. Alf Payne. Agnes
Heller. Jann Yang, Lars Jarfall and I learned a lot from him, from Emil
