Date:
Wed, 10/05/201712:00-13:30
Location:
Danciger B building, Seminar room
Lecturer: Mr. Ilya Svetlizky
Affiliation: Racah Institute of Physics,
The Hebrew University of Jerusalem
Abstract:
A dry frictional interface is composed of an ensemble of discrete contacts. Motion at each point along the interface is only initiated when contacts are broken via propagating ruptures. Characterization of the dynamic fields that drive these ruptures and how they couple to the dissipative mechanisms on the interface are therefore critical to our fundamental understanding of frictional motion and have important implications to various fields such as tribology, the fracture of weak interfaces and earthquake dynamics.
We study these frictional ruptures by performing dynamic stick-slip experiments of spatially extended acrylic blocks. The structure of these ruptures is revealed by simultaneous high-speed measurements (at μs time scales) of the real contact area and local strain field variations at the onset of motion. We first show that the strains surrounding propagating rupture tips are quantitatively described by classical singular solutions, originally derived to describe brittle shear cracks. We then demonstrate that the velocity evolution of these frictional ruptures, including their acceleration and arrest, is determined by the classical equation of motion for cracks. These observations demonstrate the extensive applicability of dynamic brittle fracture theory to friction.
Affiliation: Racah Institute of Physics,
The Hebrew University of Jerusalem
Abstract:
A dry frictional interface is composed of an ensemble of discrete contacts. Motion at each point along the interface is only initiated when contacts are broken via propagating ruptures. Characterization of the dynamic fields that drive these ruptures and how they couple to the dissipative mechanisms on the interface are therefore critical to our fundamental understanding of frictional motion and have important implications to various fields such as tribology, the fracture of weak interfaces and earthquake dynamics.
We study these frictional ruptures by performing dynamic stick-slip experiments of spatially extended acrylic blocks. The structure of these ruptures is revealed by simultaneous high-speed measurements (at μs time scales) of the real contact area and local strain field variations at the onset of motion. We first show that the strains surrounding propagating rupture tips are quantitatively described by classical singular solutions, originally derived to describe brittle shear cracks. We then demonstrate that the velocity evolution of these frictional ruptures, including their acceleration and arrest, is determined by the classical equation of motion for cracks. These observations demonstrate the extensive applicability of dynamic brittle fracture theory to friction.