[SY-O1] A numerical insight into third body flow regimes within dry contacts
In this communication we present new results related to the mechanical behavior of the solid interfacial material that is present within a dry sliding interface, and that transmits the load while accommodating the relative displacement between the surfaces - the so-called third body. To reach this purpose, an innovative numerical method is employed, based on the multibody meshfree framework. In this approach, the solid matter composing the third body is represented as a large collection of individual grains interacting by contact and adhesion, much like in the Discrete Element Modelling (DEM) framework, commonly applied in this case for the last fifteen years. However, in contrast with DEM, this new framework allows to consider each grain as highly deformable, which relaxes the assumption of a purely granular third body. In the simulations we present, 2000 such grains are placed between two rigid rough surfaces with periodic lateral boundary conditions, and these surfaces are submitted to typical tribological loadings (pressure and shear). While playing on a limited number of parameters of the third body (deformability, adhesion, damping), we observe the emergence of a very wide range of mechanical behaviors in the interface, such as granular flow, quasi-fluid Couette regime, fragile cracking, agglomeration, rolling, wall-slip, etc. The consequences of these regimes on the local friction coefficient and on the fluctuations of the loading on the surfaces in space and time (which ultimately control the degradation and the wear of these surfaces) are evaluated. Finally, comments are addressed on the possible application of such knowledge in multi-scale approaches in order to relate these results to experimental measurements.