Breakloose Suppression in Minimal Friction Models

Abstract

Abstract Breakloose friction—the transient friction force peak at the onset of sliding—is often pronounced in nanoscale contacts but weak or absent in macroscopic systems. This behavior is commonly associated with rupture fronts and process-zone effects. However, the mechanisms by which system size, temperature, driving rate, and loading geometry influence the emergence or suppression of the stiction peak remain incompletely understood. Here we investigate this problem using three minimal friction models with distinct loading geometries: a multi-particle Prandtl–Tomlinson system with independently driven particles/contacts, an end-driven Frenkel–Kontorova chain with elastic stress transmission along the interface, and a uniformly driven FK chain in which each site is coupled locally to the driving stage. We show that similar macroscopic suppression of breakloose friction can arise from fundamentally different mechanisms. In multi-particle PT systems, increasing system size or temperature promotes statistical dephasing of local depinning events, smoothing the global response. In end-driven FK chains, internal elasticity redistributes stress along the interface, delaying sliding onset and, together with higher temperature or slower driving, enabling progressive relaxation during loading. In uniformly driven FK chains, distributed loading partitions the interface into multiple local loading–relaxation domains, reducing both the breakloose peak and the mean sliding force while preserving local stick–slip dynamics. These results demonstrate that the presence or absence of a breakloose peak does not uniquely identify a single physical mechanism, but instead reflects the interplay of local pinning, elastic coupling, and contact architecture.