Effect of surface roughness on friction-induced noise: Exploring the generation of squeal at sliding friction interface

An experimental study was conducted to investigate the influence of surface sandblasting on squeal generation. A reciprocating ball-on-flat sliding configuration was used with two different arrangements that varied in mechanical characteristics. The effects of using sandblasted surfaces with different roughness on the generation and evolution of squeal were systematically investigated. The generation and intensity of squeal were suppressed and reduced with an increase in the prepared surface roughness. Both surface roughness and the wear of asperities played a key role in the triggering and evolution of squeal. Adhesion and tearing caused by the irregularities, such as the accumulation of wear debris, and particle detachment, were found likely to cause the high-frequency components of the friction force and consequently a higher squeal propensity. The real contact areas of the sandblasted surfaces, generated by the wear of asperities, comprised a discontinuously distributed “contact plateau” on which the surface features mainly indicate wear by ploughing. Therefore, the type of rough surface produced by sandblasting could significantly reduce the formation of the irregularities that in turn contribute to adhesion and tearing. Such factors indicate good potential for reducing and suppressing squeal.