The Australian Fracture Group

J R Griffiths

Background

Australia has a distinguished history of contributions to the subject of fracture mechanics. It is worthwhile setting the context for the setting up of the AFG in 1971. Important research groups in Australia at the time were at the CSIR Division of Aeronautics (later to be the (Defence) Aeronautical Research Laboratories) at Fishermans Bend, Melbourne. Full-scale fatigue tests on aircraft wings were started in the early 1940s and continue to the present day with facilities as good, or better, than any in the world. Alan Head, working in those laboratories, developed a model for fatigue crack growth (Philosophical Magazine, Vol. 44: 925-38, 1953) that pre-dated the more famous one of Paris and Erdogan. Alan was a Founder Member of the International Congress on Fracture which had its first meeting at Sendai in 1965. A second early development was the work in the 1950s and 60s by what is now the Snowy Mountains Engineering Corporation in Cooma, led by Ken Bilston, one of the last practitioners of Henri Schnadt’s ideas on brittle fracture. A third, and in the context of the Australian Fracture Group, crucial event was the setting up of the BHP Melbourne Research laboratories in Clayton in 1968 under Greg Tegart. Finally, I must mention the work in CSIRO in the 1960s led by Bob Leicester: Bob recognised that the strength of timber beams is determined by the stress intensity factor at sharp notches and this work was incorporated into the Timber Design Code and may be the earliest codified use of fracture mechanics for the integrity of engineering structures.

Early history

It was against this background that the idea for an Australian Fracture Group came about. On the initiative of several people from the BHP Laboratories, a seminar was held there in September 1970 and it was agreed to set up a Group.  The first formal meetings were held in 1971 and John Griffiths, at that time in the Monash University Department of Materials Engineering, was elected as the first President. Neil Ryan became the second President in about 1974 and continued in the post until the 1980s. Neil, Maurice de Morton and John Griffiths were all physical metallurgists as indeed were Peter Bullen from Fishermans Bend and Jack Osborn from Melbourne University, both being significant behind-the-scenes supporters. The majority of the Group were more traditional engineers. For the first two or three years we held very informal evening meetings in diverse locations ranging from a Monash lecture theatre to a pub in downtown Melbourne. Some three to four meetings were held each year. The first one-day Conference was in October 1974 and was jointly chaired by Maurice de Morton and Bob Leicester (in an interesting contrast to present day figures, the registration fee was $15 and $2 for students). The AFG remained Melbourne-centred until 1985 when the fifth AFG conference was held in Sydney. New Zealand became a member of the AFG in 1997, and the 2010 AFG Conference was held in Auckland.

International Links

The stimulus for setting up the AFG was entirely local and it is noteworthy that the AFG was the first National Fracture Group in the world. The first International Conference was held at Melbourne University in 1982. It was chaired by John Williams (Melbourne University), Rhys Jones (Aeronautical Research Laboratories) and George Sih (Lehigh University). But the largest venture of the AFG was with the International Congress on Fracture: this was ICF9, held in Sydney, jointly chaired by Bhushan Karihaloo and Yu-Wing Mai. The AFG had several early contacts with the ICF (in addition to Alan Head’s continuing membership of the Executive as a Founder Member):

     (i) Jack Osborn was elected as a Director of ICF at the Munich meeting in 1973. Subsequent office holders were John Griffiths, Bhushan Karihaloo, Yu-Wing Mai (President ICF 2001 – 2005) and, currently, Mark Hoffman. So, in a sense, the Australian Fracture Group became a formal member of ICF in 1973.

     (ii) The Second Tewkesbury Symposium was held at Melbourne University, organized by Jack Osborn and Bob Gifkins, in 1974 and, while it was a Melbourne University event, it was supported by the Australian Institute of Metals, the Institution of Engineers Australia, the AFG and the ICF. (The First Tewkesbury Symposium, also organized by Jack Osborn was held in 1966 but was of course independent of any Fracture Groups).

Comments on “The Origins of the Australian Fracture Group”, Dr F Rose

First, the 1st Tewskbury Symposium was held at Melbourne University in Aug 1963, not 1966. The keynote speaker was Alan Cottrell (probably not yet knighted). The paper containing the Bilby-Cottrell-Swinden model of fracture was published in Proc R Soc London in that same year. This model formalised an idea that Cottrell had already presented earlier in intuitive terms, and which was the theme of his keynote lecture. In my personal view, this model is a very important contribution to so-called elastic-plastic fracture mechanics. It is mathematically the same as the Dugdale model of plastic deformation at a crack tip, which, along with the key idea of plasticity-induced crack closure, which was first proposed by Wolf Elber in his PhD thesis at UNSW in 1968, underpins Jim Newman’s quite successful fatigue crack growth model. Unlike the BCS model, Dugdale’s model does not include a failure criterion: his intention was to model elongated plastic zones that had been observed experimentally in thin steel sheets.

 

Secondly, as I understood it from Peter Bullen, the King St Bridge collapse in Melbourne in 1962, which was due to brittle fracture (originating from defective welds, I believe, and brought on by extreme cold weather), was very much instrumental in raising local interest and awareness in quasi-brittle fracture, and hence in having Fracture as the topic for the 1st Tewsbury Symposium. This failure also captured attention worldwide. I am sure that I have seen a report on this failure by George Irwin. Unfortunately I don’t have the reference.

 

Finally, this may seem a bit odd, but from my perspective as a theoretician, I have always thought that an important Australian contribution to fracture research, albeit an indirect one, was the translation into English of two celebrated monographs by the Russian mathematician, N.I. Muskhelishvili, which was done circa 1952 by Rainer Radok, who was then working at the newly formed Aeronautical Research Laboratory. His translations made this monumental and definitive work widely available in the Western world. Both translations first appeared in English as ARL reports. This work was used by Alan Head and Norm Louat to formulate a dislocation model of cracking in 1955. I suspect it is this paper that led Cottrell to seek Bilby’s help with doing the theoretical analysis that resulted in the BCS model. Several decades later, Chun Wang and I used Muskhelishvili’s techniques to provide a more elegant re-formulation of self-similar fatigue crack growth that had been originally modelled by Alan Head in 1953, which was of interest to me in the context of fatigue crack growth at notches, under conditions of local cyclic plastic strain. We dedicated the paper to Alan for his 75th birthday.

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