Frictional sliding is an intrinsically complex phenomenon, emerging from the interplay between driving forces, elasto-frictional instabilities, interfacial nonlinearity and dissipation, material inertia and bulk geometry. We show that homogeneous rate-and-state dependent frictional systems, driven at a prescribed boundary velocity — as opposed to a prescribed stress — in a range where the frictional interface is rate-weakening, generically host self-healing slip pulses, a sliding mode not yet fully understood. Such velocity-driven frictional systems are then shown to exhibit coarsening dynamics saturated at the system length in the sliding direction, independently of the system’s height, leading to steadily propagating pulses. The latter may be viewed as a propagating phase-separated state, where slip and stick characterize the two phases. While the coarsening process is limited by the system’s length — leading in the presence of periodic boundary conditions to a pulse train with periodicity identical to the system’s length —, the single pulse width, characteristic slip velocity and propagation speed exhibit rich properties, which are comprehensively understood using theory and extensive numerics. Finally, we show that for sufficiently small system heights, the pulse is accompanied by periodic elasto-frictional instabilities.

摩擦滑动是一种本质上复杂的现象，源于驱动力、弹性摩擦不稳定性、界面非线性和耗散、材料惯性和体积几何形状之间的相互作用。我们展示了均匀的速率和状态相关摩擦系统，以规定的边界速度驱动——而不是规定的应力——在摩擦界面速率减弱的范围内，通常承载自愈滑动脉冲，一种滑动模式还没有完全理解。然后显示这种速度驱动的摩擦系统在滑动方向上的系统长度处表现出饱和的粗化动力学，与系统的高度无关，导致稳定传播的脉冲。后者可被视为传播相分离状态，其中滑动和粘滞表征两个相。虽然粗化过程受到系统长度的限制——在存在周期性边界条件的情况下导致周期与系统长度相同的脉冲串——但单脉冲宽度、特征滑移速度和传播速度表现出丰富的特性，综合使用理论和广泛的数字来理解。最后，我们表明对于足够小的系统高度，脉冲伴随着周期性的弹性摩擦不稳定性。