A Layer-Based Model for Frictional Sliding of Pillar Arrays

Bioinspired micropatterned surfaces have been studied as a way to enhance or control interfacial mechanical properties. Here, we study friction for the relative sliding of two interdigitated pillar surfaces. The overall frictional force originates from individual pillar-pillar interactions across the interface as well as the interpillar coupling within each substrate. In this study, we develop a layer-based physical model to simulate the contact and sliding behavior of these pillar arrays. The system is modeled as comprising four layers of nodes, with uniform shear displacement applied to the top layer, while the bottom one is held fixed. Nodes in the inner two layers represent the joints between the pillars and the substrate. The model predicts shear friction force and reveals underlying deformation mechanisms at various misorientations and height overlaps, in good agreement with measured friction in sliding experiments.