Self-affine roughness influence on the friction coefficient for rubbers onto solid surfaces

Area of Science:

• Tribology
• Materials Science
• Surface Physics

Background:

• Friction is a critical property in many mechanical systems.
• Understanding the influence of surface topography on friction is essential for material design.
• Self-affine roughness is a common characteristic of real surfaces.

Purpose of the Study:

• To investigate how self-affine surface roughness affects the friction coefficient of rubber.
• To determine the relationship between roughness parameters and friction behavior under incomplete contact.
• To analyze the influence of sliding velocity on friction under varying roughness conditions.

Main Methods:

• Characterization of surface roughness using root-mean-square (rms) amplitude (w), correlation length (xi), and roughness exponent (H).
• Experimental or computational modeling of a rubber body in incomplete contact with a solid surface.
• Measurement and analysis of the friction coefficient (mu(f)) as a function of sliding velocity and contact length scales.

Main Results:

• Increased surface roughening (decreasing H and/or increasing w/xi) shifts the maximum friction coefficient to lower sliding velocities.
• This velocity shift is observed under incomplete contact conditions for small contact length scales (lambda < xi).
• The friction coefficient consistently increases with decreasing H and/or increasing w/xi, reaching maximum values at larger contact scales (lambda >> xi).

Conclusions:

• Self-affine roughness is a key determinant of rubber friction behavior.
• Surface topography plays a crucial role in modulating friction at different sliding velocities and contact scales.
• The findings provide insights for designing surfaces with tailored friction properties.