Surface roughness as a critical parameter for frictional sliding instability: Experiments and modelling
Mechanics of Advanced Materials and Structures, vol.33, no.1, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 33 Issue: 1
- Publication Date: 2026
- Doi Number: 10.1080/15376494.2026.2636996
- Journal Name: Mechanics of Advanced Materials and Structures
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, DIALNET
- Keywords: experimental mechanics, maxwell-slip model, roughness, Sliding friction, stick-slip
- Middle East Technical University Affiliated: Yes
Abstract
Frictional sliding instability, commonly manifested as stick-slip, is of broad interest in seismology, physics, chemistry, and engineering. Although surface roughness is recognized as a key factor influencing the transition from steady sliding to stick-slip, its precise role in controlling frictional stability remains unresolved. Here, we investigate this transition using complementary friction experiments and a minimal Maxwell-slip ensemble model. PMMA plates with systematically varied roughness were subjected to normal and subsequent shear loading. The model represents the interface as independent mass-spring units governed by Coulomb friction and driven at constant velocity, with roughness incorporated probabilistically through a beta distribution of initial block positions, whose standard deviation serves as a quantitative roughness measure. Experiments and simulations show consistent trends: smoother surfaces exhibit stick-slip behavior, whereas rougher surfaces promote steady sliding. In the model, steady sliding arises from asynchronous block slip, while stick-slip corresponds to synchronous collective motion across the interface. A statistically defined critical parameter governs a sharp transition between these regimes and maps directly onto the experimentally observed roughness threshold. These results establish a mechanistic link between microscale interface disorder and macroscopic sliding stability, demonstrating that surface roughness can act as a governing parameter of frictional instability.