Digital Repository, ICF12, Ottawa 2009

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In situ three dimensional monitoring and modelling of small corner cracks in airframe Al alloys
H. Proudhon, A. Moffat, J.-Y. Buffière, I. Sinclair

Last modified: 2013-05-03


Understanding and modelling the growth of small defects (» 0.1 to 1 mm) subjected
to fatigue, represents an increasingly important aspect of airframe lifing.
There is a general understanding that in comparison to large defects, crack growth
at such small scales is influenced by several factors; these include microstructural
features (e.g. grain size and shape, boundary misorientation and second phase particle
distribution) and (micro-)mechanical aspects (e.g. stress intensity variations
across non-linear crack fronts, stress state, crack closure). In the present work,
state-of-the-art computed tomography (CT) was used to provide detailed threedimensional
(3D) quantification of the growth of small corner fatigue cracks. To
assist in the separation of microstructural and continuum mechanics contributions
to growth, testing was carried out in a commercial airframe alloy (AA2027) produced
by the conventional DC casting route, and a ‘model’ fine grained material

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