The term "contact aging" refers to the temporal evolution of the interface between a slider and a substrate usually resulting in increasing friction with time. Current phenomenological models for multiasperity contacts anticipate that such aging is not only the driving force behind the transition from static to sliding friction, but at the same time influences the general dynamics of the slidin...

Abstract Mode-coupling instabilities are known to trigger self-excited vibrations in sliding contacts. Here, the conditions for mode-coupling (or “flutter”) instability contact between a spherical oscillator and moving viscoelastic substrate studied. The work extends classical 2-Degrees-Of-Freedom conveyor belt model accounts dissipation substrate, adhesive friction at interface nonlinear norma...

A model for granular material is presented that describes both the internal deformation of each granule and the interactions between grains. The model, which is based on the FLIP-Material Point, particle-in-cell method, solves continuum constitutive models for each grain. Interactions between grains are calculated with a contact algorithm that forbids interpenetration, but allows separation and...

Integrins are cell-substrate adhesion molecules that provide the essential link between the actin cytoskeleton and the extracellular matrix during cell migration. We have analyzed alphaVbeta3-integrin dynamics in migrating cells using a green fluorescent protein-tagged beta3-integrin chain. At the cell front, adhesion sites containing alphaVbeta3-integrin remain stationary, whereas at the rear ...