Nonlinear denoising for characterization of solid friction under low confinement pressure

Area of Science:

• Tribology and Nonlinear Dynamics
• Materials Science
• Physics of Complex Systems

Background:

• Investigating paper-paper friction dynamics is crucial for understanding solid friction under low load conditions.
• Small applied loads, necessary to minimize contact damage, introduce significant noise into experimental signals.
• Traditional linear filtering methods struggle to accurately capture the asymmetric velocity profiles characteristic of friction systems.

Purpose of the Study:

• To develop advanced methods for analyzing noisy friction data from paper-paper interactions.
• To accurately characterize the transition between stick-slip and inertial friction regimes.
• To quantify the dynamics of frictional systems under low confinement pressure.

Main Methods:

• Application of nonlinear filtering techniques based on nonsmooth optimization schemes.
• Analysis of slider motion and force signals, accounting for impulsive noise.
• Development of a probability-based criterion to quantify the transition between stick-slip and inertial regimes.

Main Results:

• Nonlinear filtering successfully captures slider velocity asymmetry and pre-sliding creep motion.
• Precise estimation of stick and slip phase durations is achieved.
• A continuous transition between stick-slip and inertial regimes is observed and quantified.
• A phase diagram is generated, characterizing the system's dynamics under low confinement pressure.

Conclusions:

• Nonlinear filtering offers a robust approach for analyzing complex friction dynamics with noisy data.
• The proposed criterion effectively quantifies the transition between different friction regimes.
• The study provides a comprehensive characterization of paper-paper friction dynamics under low confinement pressure.