Alan Griffith

Following studies in mechanical engineering at the University of Liverpool, Alan Griffith worked in the Royal Aircraft Factory (later: Royal Aircraft Establishment, RAE) in Farnborough from 1915 onwards. One of his projects here involved the soap bubble analogy for torsion. His scientific interests covered a broad spectrum: applied mathematics and mechanics- especially aerodynamics and thermodynamics. In 1921 he published his famous work on fracture mechanics. Although Karl Wieghardt’s theoretical work 13 years before had shown that that stresses at the tips of cracks propagate across all boundaries [Rossmanith, 1990, pp. 535–537], Griffith’s great achievement was to consider the crack under load in the sense of an energy balance: in the equilibrium condition he equated the reduction in the elastic deformation energy stored in the material as the crack propagates with the rise in the surface energy as the area of the crack increases. According to Griffith, crack growth occurs when the deformation energy exceeds the energy required to form new surfaces. Today, his ingenious energybased crack model still forms the basis of fracture mechanics, which are used to assess steel structures subjected to fatigue, for example. Griffith worked on aerodynamic and thermodynamic problems at the RAE until 1939. He was elected to the Royal Society in 1941. From 1939 to 1960, as a senior research engineer at Rolls-Royce Aeroengines in Derby, he made great contributions to the development of aircraft engines. His name is inextricably linked with the development of VTOL aircraft, and he was able to experience proof of their viability three months after he retired.

Main contributions to structural analysis:

The phenomenon of rupture and flow in solids [1921]; The theory of rupture [1924] 

Source: Kurrer, Karl-Eugen The History of the Theory of Structures, Wilhelm Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH, Berlin (Deutschland), ISBN 3-433-01838-3, 2008; p. 734