Brake-noise challenge in the automobile industry

Abstract

Brake noises generated during vehicle operation are caused by nonlinear structural behavior that is difficult to model analytically. Noises, predominantly contact related, falling in this group can be classified into two categories based on the frequencies at which they occur: (1) brake squeal in kHz ranges; (2) brake moan and groan in 100–300 Hz range. These noises may often be accompanied by structural instability caused by some, if not all, of the following phenomena: (1) lining deformation; (2) negative slope in friction-velocity characteristic; and (3) stick-slip. In addition to the aforementioned phenomena, coupled resonance of brake components is also a necessary condition of the brake-noise generation. Currently, vehicle brake-noise design prevention is still based on a trial and error basis. No reliable design prevention tool is yet established. Although computer simulations were sometimes used to predict the structural instabilities, no clear understanding of the link between structural instabilities and radiated noise has been established. The major challenge to automobile noise control engineers will be to establish a noise radiation model which could identify the influence of the key design parameters on the noise level.