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Noise amplification in frictional systems: Oscillatory instabilities
Joyjit Chattoraj1, Oleg Gendelman2, Massimo Pica Ciamarra1,3
1School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore.
Physical Review. E
|November 28, 2019
Summary
Frictional granular materials can become unstable due to complex eigenvalues, leading to large, amplified perturbations that cause catastrophic plastic events. This study explores instability scaling and its relevance to earthquakes and friction transitions.
Area of Science:
- Physics of granular materials
- Nonlinear dynamics
- Geophysics
Background:
- Frictional granular materials can exhibit instabilities characterized by complex eigenvalues in their stability matrix.
- These instabilities lead to oscillatory exponential growth of perturbations, amplified by nonlinearities.
Purpose of the Study:
- Explore scaling laws for the onset of instability in frictional granular materials.
- Investigate instability development scenarios with and without damping.
- Characterize the nature of system-spanning plastic events.
Main Methods:
- Analysis of stability matrices and eigenvalue behavior.
- Numerical simulations to explore instability dynamics.
- Theoretical modeling of scaling laws.
Main Results:
- Identified scaling laws governing the onset of frictional instability.
- Observed different instability development paths with and without damping.
- Characterized the catastrophic, system-spanning nature of plastic events.
Conclusions:
- Instability in granular materials involves complex eigenvalues and amplified perturbations.
- Understanding these instabilities is crucial for earthquake physics and friction dynamics.
- The findings provide insights into transitions from static to dynamic friction.
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