For the sake of respect of environmental criteria about acoustic pollution and customer's satisfaction, noises due to friction-induced vibrations, in particularly squeal, are a major preoccupation of automotive manufacturers and scientist communities. As this highly fugitive phenomenon originates from complex phenomena at the frictional interface between the brake pads and the disc, it is necessary to precisely model the real contact interface evolution and associated uncertainty as a function of different topology of pads. To achieve this objective, optical measurements can be used to represent the real topography of contact surface between disc and pad. A focus is here proposed to present the numerical method, specifically developed to account for some limitations of the data acquisition system. A multiscale decomposition is performed to extract different forms, waviness, roughness and associated correlation functions representative of a family of pads produced by different manufacturers. In the current study, different morphologies of pads (without slot, diagonal slot, vertical slot, …) have been considered too. Coupling the topographical results to those obtained with dynamic sound test, the link between topography parameters and squeal frequency is investigated for pads and specifically presented for those with a vertical slot. Moreover, additional interrupted tests are performed to obtain surface morphologies just after squeal emission and a multiscale decomposition allows to discuss of associated form and roughness.
Yassine El Attaoui, Hauts-de-France Polytechnic University, Valenciennes, France; Jérémy Sadet, Franck Massa, Thierry Tison, Laurent Coustenoble, Maxence Bigerelle; Jeongkyu Kim, Hyundai Motors Group, Korea