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Synchrotron X-ray microtomography imaging was used to study crack
propagation taking into account the 3D nature of the crack morphology. A small
loading device, which is directly mounted on the tomography set-up, enabled for
in-situ loading and cycling of pre-cracked specimens. Scans were acquired during
loading and unloading of the specimen to provide 3D images of the bulk in the
vicinity of the crack at different fractions of the total propagation life. The
tomographic images were subsequently treated by 3D Digital Image Correlation
(DIC). DIC has already been used to measure Crack Opening Displacement
(COD) and to estimate the corresponding stress intensity factor (SIF) value at the
specimen surface [1]. However, up to now it has been performed in 2D only
because 3D extensions of DIC are still new [2]. In the present work, the
application of 3D-DIC to tomographic data allowed rapid retrieving of the
displacement field in the bulk of the cracked specimen. From this displacement
field, both the crack geometry and COD could be obtained.