3-Dimensional analysis of fatigue crack fields and crack growth by in situ synchrotron X-ray tomography

The propagation rate of a fatigue crack in nodular cast iron, loaded cyclic tension, has been studied situ by X-ray computed tomography and digital volume correlation. semi-elliptical initiated from an asymmetric corner notch evolved to semi-circular shape, initially with higher growth towards one edge the before along front became essentially independent position. phase congruency displacement field was used measure shape. three-dimensional stress intensity factors were calculated via linear elastic finite element model that fields around as boundary conditions. Closure tip region observed. change local mode I opening determined front.