title: Self-replicating cracks: a collaborative fracture mode in thin films.
abstract: Straight cracks are observed in thin coatings under residual tensile stress, resulting into the classical network pattern observed in china crockery, old paintings, or dry mud. Here, we present a novel fracture mechanism where delamination and propagation occur simultaneously, leading to the spontaneous self-replication of an initial template. Surprisingly, this mechanism is active below the standard critical tensile load for channel cracks and selects a robust interaction length scale on the order of 30 times the film thickness. Depending on triggering mechanisms, crescent alleys, spirals, or long bands are generated over a wide range of experimental parameters. We describe with a simple physical model, the selection of the fracture path and provide a configuration diagram displaying the different failure modes.
authors.affiliation: PMMH, CNRS UMR 7636, UPMC Université Paris 6, and Université Paris Diderot Paris 7, ESPCI-ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France and SVI, CNRS UMR 125, Saint-Gobain Recherche, BP 135, 93303 Aubervilliers Cedex, France.
authors.forename: Joël
authors.initials: J
authors.lastname: Marthelot
authors.affiliation: PMMH, CNRS UMR 7636, UPMC Université Paris 6, and Université Paris Diderot Paris 7, ESPCI-ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Roman
authors.affiliation: PMMH, CNRS UMR 7636, UPMC Université Paris 6, and Université Paris Diderot Paris 7, ESPCI-ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France.
authors.forename: José
authors.initials: J
authors.lastname: Bico
authors.affiliation: SVI, CNRS UMR 125, Saint-Gobain Recherche, BP 135, 93303 Aubervilliers Cedex, France.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Teisseire
authors.affiliation: SVI, CNRS UMR 125, Saint-Gobain Recherche, BP 135, 93303 Aubervilliers Cedex, France.
authors.forename: Davy
authors.initials: D
authors.lastname: Dalmas
authors.affiliation: Departamento de Física, Universidad de Santiago de Chile, Avenida Ecuador 3493, 9170124 Estación Central, Santiago, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Melo