title: Non-monotonic dependence of the friction coefficient on heterogeneous stiffness.
abstract: The complexity of the frictional dynamics at the microscopic scale makes difficult to identify all of its controlling parameters. Indeed, experiments on sheared elastic bodies have shown that the static friction coefficient depends on loading conditions, the real area of contact along the interfaces and the confining pressure. Here we show, by means of numerical simulations of a 2D Burridge-Knopoff model with a simple local friction law, that the macroscopic friction coefficient depends non-monotonically on the bulk elasticity of the system. This occurs because elastic constants control the geometrical features of the rupture fronts during the stick-slip dynamics, leading to four different ordering regimes characterized by different orientations of the rupture fronts with respect to the external shear direction. We rationalize these results by means of an energetic balance argument.
authors.affiliation: 1] CNR-SPIN, Dep. of Physics, University of Naples "Federico II", Naples, Italy [2] Dep. of Mathematics and Physics, Second University of Naples and CNISM, Caserta, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Giacco
authors.affiliation: 1] CNR-SPIN, Dep. of Physics, University of Naples "Federico II", Naples, Italy [2] Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore.
authors.forename: M Pica
authors.initials: MP
authors.lastname: Ciamarra
authors.affiliation: Dep. of Industrial and Information Engineering, Second University of Naples and CNISM, Aversa (CE), Italy.
authors.forename: L
authors.initials: L
authors.lastname: Saggese
authors.affiliation: Dep. of Industrial and Information Engineering, Second University of Naples and CNISM, Aversa (CE), Italy.
authors.forename: L
authors.initials: L
authors.lastname: de Arcangelis
authors.affiliation: Dep. of Mathematics and Physics, Second University of Naples and CNISM, Caserta, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Lippiello