Disc brake squeal generation during dry and wet conditions

Abstract

Brake squeal, is an annoying sound that occurs in the frequency range of 1 to 20 k Hz and typically measures above 70 dB(A). To date, there have been extensive works carried out to identify significant parameters or mechanisms that trigger squeal occurrences based on various disciplinces such as structural dynamics and tribology. However, it seems that there is a limited study conducted to relate brake squeal with wet conditions of the brake pad. Thus, this work attempts to explore disc brake squeal generation and its establishment during the dry and wet conditions. A series of brake squeal tests is performed according to SAE J2521 test procedure using laboratory brake noise test rig. Three wet conditions are considered that based on levels of water absorption in the brake pad. It is found that the dry brake pad produces less numbers of squeal occurrence compared to the three wet pads. The dry pad records sound pressure level below 100 dB(A) while all three wet pads produce squeal sound more than 100 dB(A). It is observed that brake squeal can also be triggered and influenced by different operating and environment conditions due to dry and wet brake pads. The wet pads are producing brake squeal at wide range of operating and environment conditions compared to the dry pad.