title: Crack Front Segmentation and Facet Coarsening in Mixed-Mode Fracture.
abstract: 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.
authors.affiliation: Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA.
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Laboratoire FAST, Univ Paris Sud, CNRS, Université Paris-Saclay, F-91405 Orsay, France.
authors.forename: Tristan
authors.initials: T
authors.lastname: Cambonie
authors.affiliation: Laboratoire FAST, Univ Paris Sud, CNRS, Université Paris-Saclay, F-91405 Orsay, France.
authors.forename: Veronique
authors.initials: V
authors.lastname: Lazarus
authors.affiliation: Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA.
authors.forename: Matteo
authors.initials: M
authors.lastname: Nicoli
authors.affiliation: Department of Physics, Polytechnic University of Catalonia, Terrassa, Barcelona 08222, Spain.
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Pons
authors.affiliation: Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA.
authors.forename: Alain
authors.initials: A
authors.lastname: Karma