ESPCI web site
with V. Fazio and V. Acito
Collaboration with Hutchinson, Montargis and F. Amiot, FEMTO, Besançon
Transient frictional regimes have long been recognized to involve complex history effects which remains essentially described within the frame work of phenomenological models. In order to address the underlying physical mechanisms, we carry out friction experiments where the contact interface is perturbed by non rectilinear sliding trajectories. As an example, controlled transient friction is achieved by imposing a sinus wave motion to a spherical glass probe in contact with a plane rubber substrate, while measuring the two components of the friction force within the contact plane (Fig.a). We find that the friction force is not tangent to the trajectory (Fig.b) as a result of the non-uniform distribution of the sliding velocity within the contact interface (Fig.c)These observations are accounted for by a friction model which takes into account heterogeneous displacements within the contact area
(a) Contact between a rubber substrate and a spherical glass probe under sinus wave motions. (b) Red arrows : Orientation of the friction force along the imposed trajectory (blue line) (c) Red arrows : Sliding velocity field measured within and around the contact. Blue line : contact edge
References
V. Fazio, V. Acito, F. Amiot, C. Frétigny and A. Chateauminois, Memory effects in friction : the role of sliding heterogeneities, Proceedings of the Royal Society A 477 (2021) 20210559