Classical shear cracks drive the onset of dry frictional motion

Ilya Svetlizky, Jay Fineberg*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

185 Scopus citations


Frictional processes entail the rupture of the ensemble of discrete contacts defining a frictional interface. There are a variety of views on how best to describe the onset of dry frictional motion. These range from modelling friction with a single degree of freedom, 'a friction coefficient', to theoretical treatments using dynamic fracture to account for spatial and temporal dynamics along the interface. We investigated the onset of dry frictional motion by performing simultaneous high-speed measurements of the real contact area and the strain fields in the region surrounding propagating rupture tips within the dry (nominally flat) rough interfaces formed by brittle polymer blocks. Here we show that the transition from 'static' to 'dynamic' friction is quantitatively described by classical singular solutions for the motion of a rapid shear crack. We find that these singular solutions, originally derived to describe brittle fracture, are in excellent agreement with the experiments for slow propagation, whereas some significant discrepancies arise as the rupture velocity approaches the Rayleigh wave speed. In addition, the energy dissipated in the fracture of the contacts remains nearly constant throughout the entire range in which the rupture velocity is less than the Rayleigh wave speed, whereas the size of the dissipative zone undergoes a Lorentz-like contraction as the rupture velocity approaches the Rayleigh wave speed. This coupling between friction and fracture is critical to our fundamental understanding of frictional motion and related processes, such as earthquake dynamics.

Original languageAmerican English
Pages (from-to)205-208
Number of pages4
Issue number7499
StatePublished - 2014

Bibliographical note

Funding Information:
Acknowledgements This work was supported by the James S. McDonnell Fund, the European Research Council (grant no. 267256) and the Israel Science Foundation (grant 76/11). We thank E. Bouchbinder and G. Cohen for comments. We especially thankM.Adda-Bediafor insightsthat helpedusunderstandthe data’srelationtoLEFM.


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