This special issue of Philosophical Magazine contains invited papers to celebrate the life and 80th birthday of Professor Anthony Kelly, a truly outstanding Materials Scientist. The Guest Editors are very pleased to have had the opportunity of participating in the preparation of the present collection of invited contributions in those areas of materials science to which Anthony has contributed. A time-line of the many milestones of Tony’ s glittering career is given at the end of this Introduction, and it provides much additional information concerning his achievements and very high esteem. The invited Preface following this Introduction presents his own thoughts on many aspects of both his career and scientific activities.
Tony’ s early scientific work related to X-ray and electron microscope studies of precipitation and dispersion hardened alloys. In 1963 with Robin Nicholson (now Sir Robin) he produced the first synthesis, which has stood the test of 40 years, relating the type of dispersion to the work hardening characteristics of metals. This work has become a classic reference of the Science Citation Index. He pointed out clearly the nature of the criterion for metals to exhibit polycrystalline ductility by glide, and he applied this to important ceramic and other inorganic materials that were becoming available in the ‘60s and ‘70s. He applied the same ideas to the climb of dislocations. This led to a criterion for distinguishing fundamentally between brittle and ductile crystals, and to detailed calculations of the ideal strength of crystals. He set down the principles of the materials science of metallic composite materials, particularly the strength, toughness and creep of short fibre composites, and led the way to relating fibre reinforcement and conventional strengthening methods of metals. This was followed by the experimental analysis of fibre bundle failure.
One seminal paper written at Cambridge University (Kelly & Tyson, JMPS, 1965) concerns the tensile properties of both continuous and discontinuous fibre-reinforced metal composites (copper/tungsten and copper/molybdenum systems), and is the most cited of all Kelly’ s works – at the time of writing just over 900 citations according to the Web of Science, of which around 30 are in 2010, showing how relevant this article has remained. The paper describes load transfer from fibre to matrix in the case of a plastically yielding matrix where the interfacial shear stress varies linearly from its maximum value at a fibre break or fibre end to zero at the elastic/plastic boundary. This model led to the concept of critical stress-transfer lengths (or ineffective lengths) that must be exceeded if the fibre is to fail, and which continues to be a very widely used concept in the composites field. The paper also introduced the widely used concept of fibre pull-out having examined fracture surfaces, and introduced the idea of having a pull-out test to determine the interfacial shear stress resulting from matrix yielding. This body of work, now summarised in nearly any book on composite materials, also included several other seminal contributions; for example a first observation of the plasticity size-effect in composites (Kelly and Lilholt, Phil. Mag. 1969), which was offered with an interpretation that was questioned by many but in the end was a proven concept.
In the early ‘70s he explored for the first time the phenomenon of multiple fracture of a fibrous composite in detail, a question that has remained to this day an active and intriguing subject of research. This work explained the properties of fibre reinforced cements and concretes, which has underpinned the whole development of ceramic composite materials as well as contributing to the understanding of the modes of toughness of laminated composite structures with resin matrices. A particular seminal scientific contribution in this context is summarised in a 1973 paper. This micro-mechanics analysis is often referred to in the literature as ACK theory (Aveston, Cooper, Kelly), which is key to the subject for two principal reasons. The first is that it developed the first stress-transfer model that enabled the estimation of load transfer from matrix to fibres in a brittle-matrix composite having arrays of matrix cracks normal to the fibre direction. When matrix cracks form normal to the fibre direction, fibre/matrix debonding occurs introducing the additional difficulty of dealing with interfacial friction. This is characterised by a critical frictional interfacial shear stress that is now extensively used in damage models and measured by experiment. The second is that the paper is the first elucidation of the subject named many years later as ‘finite fracture mechanics’. Traditional fracture mechanics considers the stability of cracks by studying energy changes during their incremental growth. Finite fracture mechanics considers energy differences between an uncracked sample and one in which a fully developed crack has formed, just as in the matrix cracking phenomenon of ACK theory. The passage of many years since has shown that ACK theory and conventional fracture mechanics are exactly equivalent when considering the growth of fully bridged long cracks. ACK theory provides a very compact analytical expression for the matrix cracking stress that is immensely useful when considering the resistance of brittle matrix composites to damage formation. The 1973 paper on matrix cracking was published in the same year that Anthony's scientific achievements were recognised by his election as a Fellow of the Royal Society.
In the 1990s, Graham Parkhouse and he established the fundamental limits to the attainable packing density of assemblies of long straight fibres and supported this with experiment in order to establish the possible most dense packing of random fibre arrangements, and of those regular fibre arrangements which can produce elastic isotropy. Since 2000 Tony's principal interest has been using composite principles to control and to modify the thermal expansion coefficients of materials so as to obtain hitherto unattained values and to obtain these with a desirable combination of other properties; work undertaken at the Gordon Laboratory, University of Cambridge. It was the setting up of the Gordon Laboratory in 1999 that led to the establishment of the Kelly Lecture, supported by the Armourers and Brasiers, and which takes place at the end of each Academic year. During his scientific career Anthony Kelly has written over 200 papers in scientific and technical journals, written two books and edited four major publications concerning composite materials.
During the period 1967–1975 he was employed by the Scientific Civil Service at the National Physical Laboratory and took on very significant administrative responsibilities, but always remained in intimate contact with the scientific activity, a very unusual combination of vital talents. In 1975, he was appointed Vice-Chancellor and Chief Executive of Surrey University and took on even more administrative responsibility, but always managed to find some time to indulge in his passion for materials science. As a materials scientist he was an inspirational figure to many colleagues in the Department of Materials Science and Engineering at the University. He contributed a great deal to the University of Surrey over his nineteen years’ tenure as its Vice-Chancellor; but his most enduring legacy is perhaps the Surrey Research Park, established during his Vice-Chancellorship, which is currently home to well over 100 companies and is recognised as one of the best of its kind in the UK. During this period, in 1988, Anthony Kelly was honoured by being appointed Commander of the British Empire (CBE) on the occasion of the Queen's official birthday; for services to science and engineering. In parallel with his scientific and administrative duties, Anthony was also able to interact strongly with manufacturing industry (e.g. ICI, Rolls Royce, Johnson Wax to name a few). Anthony has worked for periods in the USA, Germany and in Switzerland. He has an interest in the linguistic aspects of science and is an Honorary Fellow of the Institute of Linguists.
This introduction cannot be complete without highlighting Tony's many personal qualities that have significantly influenced so many other people around him. His enthusiasm for materials science is exceptional and contagious. His determination to understand in the greatest depth, and in full rigour, the many questions he addresses has been an inspiration to many of his colleagues. His intellect and his wit are truly unique, and make him stand out as one of the most personable and interesting members of our community. He also has a singular ability to simultaneously take under his wing and continuously challenge his younger colleagues, a combination that makes him an exceptional mentor. Over the many years of his illustrious career Anthony Kelly has been a guide, a source of inspiration, and a model to a great many of today's materials scientists.
L.N. McCartney
NPL, Teddington, UK
W.J. Clegg
University of Cambridge, Cambridge, UK
A. Mortensen
EPFL, Lausanne, Switzerland
P.A. Smith
University of Surrey, Guildford, UK
Timeline to date for life and career of Anthony Kelly, CBE, FRS
1929 Born 25 January, Hillingdon, Middlesex, UK
1940 Entered Presentation College, Reading
1946 Gained Open Scholarship to University of Reading
1949 Gained B.Sc. (1st in Physics) University of Reading
1953 Gained Ph.D., Trinity College, Cambridge
Appointed Research Associate, University of Illinois (to 1955)
1955 Appointed ICI Fellow, University of Birmingham
1956 Married Christina Margaret Dunleavie deceased 1997 (3 sons, 1 daughter)
Appointed Assistant, later Associate Professor, The Technological Institute, Northwestern University, Chicago, (to 1959)
1959 Appointed Lecturer, University of Cambridge (to 1967)
1960 Founding Fellow of Churchill College, Cambridge and Director of Studies in Natural Sciences
1966 Publication of book ‘Strong Solids’, 1st ed.
1967 Appointed Superintendent Division of Inorganic and Metallic Structure, at the National Physical Laboratory (to 1969)
Awarded William Hopkins Prize, Cambridge Philosophical Society
Awarded Beilby Medal, Royal Institution of Chemistry
Visiting Professor, Carnegie Institute of Technology
Member of Committee, Science Research Council (to 1972)
1968 Awarded Sc.D. of University of Cambridge
1969 Appointed Deputy Director, National Physical Laboratory in charge of Materials Group (to 1975)
Member of Council, Institute of Metals (to 1974)
1970 Publication of book ‘Crystallography and Crystal Defects’, 1st ed. (with G.W. Groves).
Member of Council, later Director, British Non-Ferrous Metals Research Association (to 1973)
1973 Elected Fellow of the Royal Society
Seconded to ICI plc as part of Government/Industry/Academia Task Force (to 1975)
Member (to 1975), then Chairman (to 1980) of Engineering Requirements Board, Dept. of Industry
Member of Advisory Committee, Community Reference Bureau, EEC (to 1975)
1974 Awarded A A Griffith Medal (now awarded by IoM3)
1975 Appointed Vice-Chancellor and Chief Executive, Surrey University (to 1994)
Founding member of the International Conference on Composite Materials (ICCM), an on-going series of 17 conferences held to date
1977 Professeur Invité, Ecole Polytechnique Fédérale de Lausanne, Switzerland
1979 Founded Surrey Research Park, Guildford
Elected Fellow of the Fellowship (now Royal Academy) of Engineering
1981 Director of Johnson Wax UK Ltd. (to 1996)
1984 Founder Member and later President, European Association Composite Materials
First co-recipient of Medal of Excellence in Composite Materials, University of Delaware
Director of QUO-TEC Ltd. (to 2000)
1985 Chairman Surrey Satellite Technology (to 1995)
Elected Extraordinary Fellow of Churchill College (to 1996 – Now Pensioner Fellow for life)
1986 Elected Foreign Associate of the US Academy of Engineering
Publication of 3rd ed. (with N.H. McMillan) of book ‘Strong Solids’
Publication of Handbook of Composites (Co-Editor with Yuri Rabotnov)
Publication of Encyclopedia of Materials Science and Engineering (Subject Editor for Composite Materials)
1987 Elected University Professor, University of Surrey
1988 Awarded CBE in Queen's Birthday Honours
Elected Honorary Fellow, Roehampton Institute
Elected Honorary Fellow of the Institute of Linguists
1989 Chairman of Joint Standing Committee on Structural Safety, Insts. Civil & Struct. Engrs. (to 1998)
Vice-President, Royal National Institute for the Deaf (to 1998)
Publication of Concise Encyclopedia of Composite Materials
Member of Management Committee, and Chairman, Canada Memorial Foundation (to 1998)
1990 Elected to the Academia Europaea
1991 Awarded International Gold Medal of American Society of Materials
1992 Awarded Platinum Medal of the Institute of Materials
Appointed a Knight of St Gregory
1993 Appointed a Deputy Lieutenant for the County of Surrey
1994 D. Univ., University of Surrey
Distinguished Research Fellow, Department of Materials Science and Metallurgy, University of Cambridge
1995 Senior Vice-President, Institute of Materials, UK
Appointed Director, NPL Management Ltd. (to 2001)
1996 President Institute of Materials, UK (to 1997)
Elected Honorary Fellow Institution of Structural Engineers
1997 Hon. D.Sc. University of Birmingham
Elected Honorary Fellow Institution of Civil Engineers
Editor in Chief, Comprehensive Composite Materials
1998 President of Honour, European Society for Composite Materials
1999 Publication of 2nd ed. (with G.W. Groves and P. Kidd) of book ‘Crystallography and Crystal Defects’
Lee Kuan Yew Distinguished Visitor to the Commonwealth of Singapore
2000 Awarded Acta Metallurgica Gold Medal
2001 Honorary D.Eng., Hanyang University, Korea
Honorary Doctor of Science, University of Reading
Elected World Fellow of the International Committee on Composite Materials
2003 Doctor Honoris Causa of Engineering, University of Navarra
2004 Awarded James Alfred Ewing Medal by Institution of Civil Engineers
Awarded Leverhulme Fellowship entitled ‘Matching CTE of Silicon’ to 2006.