Scalar model for frictional precursors dynamics

Abstract

Recent experiments indicate that frictional sliding occurs by nucleation of detachment fronts at the contact interface that may appear well before the onset of global sliding. This intriguing precursory activity is not accounted for by traditional friction theories but is extremely important for friction dominated geophysical phenomena as earthquakes, landslides or avalanches. Here we simulate the onset of slip of a three dimensional elastic body resting on a surface and show that experimentally observed frictional precursors depend in a complex non-universal way on the sample geometry and loading conditions. Our model satisfies Archard's law and Amontons' first and second laws, reproducing with remarkable precision the real contact area dynamics, the precursors' envelope dynamics prior to sliding, and the normal and shear internal stress distributions close to the interfacial surface. Moreover, it allows to assess which features can be attributed to the elastic equilibrium, and which are attributed to the out-of-equilibrium dynamics, suggesting that precursory activity is an intrinsically quasi-static physical process. A direct calculation of the evolution of the Coulomb stress before and during precursors nucleation shows large variations across the sample, explaining why earthquake forecasting methods based only on accumulated slip and Coulomb stress monitoring are often ineffective.

Rupture Dynamics of Heterogeneous Frictional Interfaces

“…While these events induce local slip at points traversed by the partial rupture, macroscopic sliding of the surfaces will not occur, as the surfaces remain pinned at points beyond the rupture arrest locations. This type of event has been referred to in the literature as a precursor to sliding motion (Bar‐Sinai et al, ; Braun et al, ; Kammer et al, ; Katano et al, ; Maegawa et al, ; Radiguet et al, ; Rubinstein et al, ; Scheibert & Dysthe, ; Taloni et al, ; Tromborg et al, ). The mechanisms of rupture arrest will be discussed in detail in section 4.…”

“…The overall sliding motion of a finite‐size system only initiates when a rupture front has traversed the entire interface (Rubinstein et al, ). When the applied loading is not spatially homogeneous, rupture fronts can propagate prior to the onset of motion, arresting before spanning the entire interface (Bar‐Sinai et al, ; Bayart et al, ; Braun et al, ; Kammer et al, ; Katano et al, ; Maegawa et al, ; Radiguet et al, ; Rubinstein et al, ; Scheibert & Dysthe, ; Taloni et al, ; Tromborg et al, ). Arrested ruptures are of particular interest for two reasons.…”

Probing Locally the Onset of Slippage at a Model Multicontact Interface

“…All curves at different v are found to overlap on the same master curve, suggesting that propagation of slip precursors results from a quasi-static mechanism. Quasi-static slip precursors have already been reported numerically [9,26,27] but not experimentally, and its underlying physics remains elusive. In an attempt to provide an answer within the framework of our measurements, let us model our system with asperities distributed along y (the direction normal to the iso-pressure lines) on a unidimensional regular lattice of lattice constant b, and let us neglect the elastic interaction between them (i.e.…”

Minimal model for slow, sub-Rayleigh, supershear, and unsteady rupture propagation along homogeneously loaded frictional interfaces

“…The range of observed front types have already been successfully reproduced by a variety of models. Arrested cracks have been reproduced using quasi-static models [18][19][20][21], or elastodynamic models in 1D [22,23] or 2D [24][25][26][27][28], assuming either continuous [19,[22][23][24][25]27] or discrete-microcontact-based friction laws [26,28], or fracture concepts [18,21]. Slip pulses have been reproduced using discrete [29] or continuum models assuming either a Coulomb [30], regularized Coulomb [31][32][33] or state-andrate [34,35] friction laws.…”