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The Weibull distribution is by
far the world’s most popular statistical model for life data. It is
also used in many other applications, such as weather forecasting and
fitting data of all kinds. Among all statistical techniques it may be
employed for engineering analysis with smaller sample sizes than any
other method. Having researched and applied this method for almost
half a century, I am honored to be asked to write this short biography
of this remarkable man from Sweden.
Wallodi Weibull was born on June
18, 1887. His family originally came from Schleswig-Holstein, at that
time 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 was a midshipman in the Royal
Swedish Coast Guard in 1904 was promoted to sublieutenant in 1907,
Captain in 1916, and Major in 1940. He took courses at the Royal
Institute of Technology where he later became a full professor (1924)
and graduated in 1924. His doctorate is from the University of Uppsala
in 1932. He worked in Swedish and German industries as an inventor
(ball and roller bearings, electric hammer) and as a consulting
engineer. My friends at SAAB in Trollhatten Sweden gave me some of
Weibull’s papers. SAAB is one of many companies that employed
Weibull as a consultant.
His first paper was on the
propagation of explosive wave in 1914. He took part in expeditions to
the Mediterranean, the Caribbean, and the Pacific ocean on the
research ship "Albatross" where he developed the technique
of using explosive charges to determine the type of ocean bottom
sediments and their thickness, just as we do today in offshore oil
exploration.
In 1941 BOFORS, a Swedish arms
factory, gave him a personal research professorship in Technical
Physics at the Royal Institute of Technology, Stockholm.
He published many papers on
strength of materials, fatigue, rupture in solids, bearings, and of
course, the Weibull distribution. The author has identified 65 papers
to date plus his excellent book on fatigue analysis (1), 1961. 27 of
these papers were reports to the US Air Force at Wright Field on
Weibull analysis. (Most of these reports to WPAFB are no longer
available even from NTIS. The author would appreciate copies.) Dr.
Weibull was a frequent visitor to WPAFB and many of our universities.
His most famous paper (2), at
least in the USA, was given before the ASME in 1951, seven case
studies using the Weibull distribution. Many including the author were
skeptical that this method of allowing the data to select the most
appropriate distribution from the broad family of Weibull
distributions would work. However the early success of the method with
very small samples at Pratt & Whitney Aircraft could not be
ignored. Further, Dorian Shainin, a consultant for Pratt &
Whitney, strongly encouraged the use of Weibull analysis. The author
soon became a believer.
Robert Heller (3) spoke at the
1984 Symposium to the Memory of Waloddi Weibull in Stockholm, Sweden
and said,
In 1963, at the invitation
of the Professor Freudenthal, he became a Visiting Professor at
Columbia University’s Institute for the Study of Fatigue and
Reliability. I was with the Institute at that time and got to know
Dr. Weibull personally. I learned a great deal from him and from
Emil Gumbel and from Freudenthal, the three founders of
Probabilistic Mechanics of Structures and Materials. It was
interesting to watch the friendly rivalry between Gumbel, the
theoretician and the two engineers, Weibull and Freudenthal.
"The Extreme Value
family of distributions, to which both the Gumbel and the Weibull
type belong, is most applicable to materials, structures and
biological systems because it has an increasing failure rate and
can describe wear out processes. Well, these two men, both in
their late seventies at the time, showed that these distributions
did not apply to them. They did not wear out but were full of life
and energy. Gumbel went skiing every weekend and when I took Dr.
and Mrs. Weibull to the Roosevelt Home in Hyde Park on a cold
winter day, he refused my offered arm to help him on the icy
walkways saying: " A little ice and snow never bothered a
Swede."
In 1972, the American Society of
Mechanical Engineers (4) awarded Dr. Weibull their gold medal citing
Professor Weibull as "a pioneer in the study of fracture,
fatigue, and reliability who has contributed to the literature for
over thirty years. His statistical treatment of strength and life has
found widespread application in engineering design." The award
was presented by Dr. Richard Folsom, President of ASME, and President
of Rensselaer Polytechnic Institute when the author was a student
there. By coincidence the author received the 1988 ASME gold medal for
statistical contributions including advancements in Weibull analysis.
The author has an unconfirmed
story told by friends at Wright Patterson Air Force Base that Dr.
Weibull was in a great state of happiness on his last visit to lecture
at the Air Force Institute of Technology in 1975 as he had just been
married to a pretty young Swedish girl. He was 88 years old at the
time. His first wife has passed on earlier. It was on this trip that
the photo above was take at the University of Washington where he also
lectured.
The US Air Force Materials
Laboratory should be commended for encouraging Wallodi Weibull for
many years with research contracts. The author is also indebted to
WPAFB for contracting the original USAF Weibull Analysis Handbook (5)
and Weibull video training tape, as he was the principal author of
both. The latest version of that Handbook is the fourth edition of The
New Weibull Handbook (6).
Professor Weibull’s proudest
moment came in 1978 when he received the Great Gold medal from the
Royal Swedish Academy of Engineering Sciences which was personally
presented to him by King Carl XVI Gustav of Sweden.
He was devoted to his family and
was proud of his nine children and numerous grand and
great-grandchildren.
Dr. Weibull was a member of many
technical societies and worked to the last day of his remarkable life.
He died on October 12, 1979 in Annecy, France.
The Weibull Distribution was
first published in 1939, over 60 years ago and has proven to be
invaluable for life data analysis in aerospace, automotive, electric
power, nuclear power, medical, dental, electronics, every industry.
Yet the author is frustrated that only three universities in the USA
teach Weibull analysis. To encourage the use of Weibull analysis the
author provides free copies of The New Weibull Handbook to university
libraries in English speaking countries that request the book. The
corresponding SuperSMITH software is available from Wes Fulton in demo
version free from his Website. Click
here to visit Weibullnews.com
The author would appreciate
comments and questions about Wallodi Weibull and Weibull analysis.
E-mail: weibull@worldnet.att.net
Mail: 536 Oyster Road, North Palm Beach, Florida, 33408. Phone/FAX
561-842-4082.
References:
1. Weibull, Waloddi, "Fatigue
Testing and Analysis of Results", Pergamon Press,
1961.
2. Weibull, Waloddi, "A
Statistical Distribution Function of Wide Applicability,"
Journal of Applied Mechanics, 1951.The
hallmark paper of Weibull analysis...and easy reading.
3. S. Eggwertz & N.C. Lind,
Editors:"Probabilistic Methods in the Mechanics of Solids and
Structures," Symposium Stockholm Sweden, June 1984, To the
Memory of Waloddi Weibull, Springer-Verlag. (The
author would love to have a copy of this if any reader can loan him
their copy to reproduce he will respond with a copy of The New Weibull
Handbook.)
4. ASME New Release: Waloddi
Weibull Receives the ASME Medal., November 1972.
5. Abernethy, Robert B.; J. E.
Breneman; C. H. Medlin; G. L. Reinman; "Weibull Analysis
Handbook", U.S. Air Force AFWAL-TR-83-2079, November 1983,
AD #A143100 Approximately 14,000 copies were distributed by the US Air
Force, Pratt & Whitney, and the author.
6. Abernethy, Robert B. "The
New Weibull Handbook," Fourth Edition, November 2000,
published by the author. ISBN 0-9653062-1-6. Over 13,000 copies are in
circulation.
7. Weibull, Waloddi, "Estimation
of Distribution Parameters by a Combination of the Best Linear Order
Statistic Method and Maximum Likelihood", USAF
AFML-TR-67-105, April 1967.
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