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Flash weakening is limited by granular dynamics
Author(s) -
Kuwano Osamu,
Hatano Takahiro
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl048530
Subject(s) - dissipation , mechanics , flash (photography) , dynamics (music) , friction coefficient , range (aeronautics) , dynamical friction , deformation (meteorology) , materials science , steady state (chemistry) , critical ionization velocity , granular material , geology , physics , classical mechanics , geotechnical engineering , thermodynamics , optics , chemistry , composite material , acoustics
We measured the steady‐state friction coefficient of granite over a wide range of sliding velocities and pressures. We observed considerable weakening, described well by a flash‐heating theory, above the sliding velocity of 1 cm/s regardless of pressure. At higher velocities, the velocity strengthening behavior replaced the velocity weakening behavior. This strengthening at higher velocities agrees with data from numerical simulations on sheared granular matter and is therefore described in terms of energy dissipation due to the inelastic deformation of grains. We propose a unified steady‐state friction law that well describes the velocity and pressure dependence of the steady‐state friction coefficient.