| Citation | The candidate's researches on fracture mechanics over two decades identified criteria for extension of cracks in structural metals. He contributed to the definition of crack opening displacement, devised methods for its measurement, and conducted many large-scale experiments to verify its use. He persevered with practical application of these methods to control of fracture initiation in large welded structures, firstly by the analysis of many brittle fracture casualties worldwide at the time of occurrence, and then by the development of standardised fracture toughness tests and standard methods of interpretation, including data from non-destructive methods of detecting and sizing crack-like defects. The British Standard Published Document 6493 pioneered these methods and is now in international use, not least with regard to fracture control of welded steel structures in the UK North Sea; its successful application over the past decade owes much to the candidate's personal efforts. |