Crack front segmentation and facet coarsening in mixed-mode fracture
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A planar crack generically segments into an array of “daughter cracks” shaped as tilted facets when loaded with both a tensile stress normal to the crack plane (mode I) and a shear stress parallel to the crack front (mode III). We investigate facet propagation and coarsening using in situ microscopy observations of fracture surfaces at different stages of quasistatic mixed-mode crack propagation and phase-field simulations. The results demonstrate that the bifurcation from propagating a planar to segmented crack front is strongly subcritical, reconciling previous theoretical predictions of linear stability analysis with experimental observations. They further show that facet coarsening is a self-similar process driven by a spatial period-doubling instability of facet arrays.
CitationChen, C.-H., Cambonie, T., Lazarus, V., Nicoli, M., Pons, A. J., Karma, A. Crack front segmentation and facet coarsening in mixed-mode fracture. "Physical review letters", 30 Desembre 2015, vol. 115, núm. 26.