| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 617426 | Wear | 2013 | 6 Pages |
•The normal contact stiffness of the friction material was significantly affected by the surface roughness and proportional to the tangential contact stiffness.•The normal contact stiffness affects the shape of the stick-slip profiles.•The friction force oscillation goes through transitions from stick-slip to sinusoidal oscillation and to steady sliding as the sliding velocity is increased.
The effect of the surface roughness of the brake friction material on friction-induced instability was studied. Commercial friction materials with different surface roughness levels were tested using a scale brake dynamometer to find a correlation between the surface roughness and friction oscillation. The results showed that the normal contact stiffness was strongly affected by surface roughness and played a significant role in determining the friction oscillation pattern. The friction force oscillation changed from stick-slip to sinusoidal oscillation and steady sliding as the sliding velocity increased, and the velocity ranges for different oscillatory patterns were changed by the surface roughness. A smooth surface with glazed patches produced friction oscillation with larger amplitudes, and the oscillation was maintained over a wider range of sliding velocities due to the high contact stiffness. The correlation between the contact stiffness and surface roughness suggested that friction-induced instability might be avoided by designing the friction material to have low surface stiffness.
