Partial slip in mesoscale contacts: dependence on contact size

Area of Science:

• Physics
• Materials Science
• Tribology

Background:

• Partial slip, or microslip, is a phenomenon occurring at the interface of contacting surfaces.
• Understanding partial slip is crucial for predicting friction and wear in various applications.

Purpose of the Study:

• To investigate the occurrence and magnitude of partial slip between glass spheres and polymer surfaces.
• To analyze the relationship between contact parameters, oscillation amplitude, and partial slip behavior.

Main Methods:

• Utilized acoustic resonators to measure shifts in resonance frequency (Δf) and bandwidth (ΔΓ).
• Examined the dependence of Δf and ΔΓ on oscillation amplitude to identify partial slip regimes.
• Applied two models of partial slip to derive frequency-amplitude relations from force-displacement data.

Main Results:

• Partial slip was observed as a decrease in resonance frequency (Δf) at elevated amplitudes.
• Bandwidth (ΔΓ) increased with amplitude in the partial slip regime, consistent with models.
• A transition to gross slip was observed at high amplitudes and large sphere sizes.
• In some cases, Δf was amplitude-independent at low amplitudes, indicating linear force-displacement relations.
• Partial slip was more pronounced for larger contact radii, attributed to smooth stress profiles.

Conclusions:

• Acoustic resonators effectively probe partial slip phenomena between spheres and polymer surfaces.
• The study provides insights into the transition from partial slip to gross slip.
• Contact size significantly influences the onset and extent of partial slip, with larger contacts exhibiting more pronounced effects.