J. Cirne, R. Dormeval, et al.
J. Phys. IV France 134 (2006) 597-601
Dynamic optical interferometry applied to analyse out of plane displacement fields for crack propagation in brittle materialsS. Hedan, O. Pop, V. Valle and M. Cottron
Université de Poitiers, Laboratoire de Mécanique des Solides, UMR 6610, Poitiers, France
Published online: 26 July 2006
We propose in this paper, to analyse, the evolution of out-of-plane displacement fields for a crack propagation in brittle materials. As the crack propagation is a complex process that involves the deformation mechanisms, the out-of-plane displacement measurement gives pertinent information about the 3D effects. For investigation, we use the interferometric method. The optical device includes a laser source, a Michelson interferometer and an ultra high-speed CCD camera. To take into account the crack velocity, we dispose of a maximum frame rate of 1Mfps. The experimental tests have been carried out for a SEN (Single Edge Notch) specimen of PMMA material. The crack propagation is initiated by adding a dynamic energy given by the impact of a cutter on the initial crack. The obtained interferograms are analysed with a new phase extraction method entitled MPC . This analysis, which has been developed specially for dynamic studies, gives the out-of-plane displacement with an accuracy of about 10 nm.
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