The objective of this work is to present an experimental methodology that allows a holistic interpretation of the in-service movement of a brake shoe under squeal conditions based on fluctuating acceleration data. The proposed analysis has been applied to a primary and secondary shoe of a drum brake under squeal conditions and reveals clear evidence of the complex movements that intrinsically cause the alternating force excitation responsible for the squeal. The method is carried out in the time domain, thus phase and amplitude information between the two movement components is preserved. The method is based on the synchronous measurement of acceleration data on brake component at various points and directions. The proposed analysis also reveals the actual velocity and displacement patterns of a brake shoe under squeal conditions and their variability along the lining material. Therefore, the method can be used to investigate drum shoe interaction in great detail and it is an effective complement to the more traditional modal analysis and running mode studies used in brakes

Garcia J.J, Squadrani F, Mateu, R., Yangwoo Park: Head of Commercial Vehicle Chassis Engineering Design Group , Jonghoon Lim: General Manager / Commercial Vehicle Chassis Engineering Team 3, Heejin Cho: Senior Research Engineer / Commercial Vehicle Chassis Engineering Team 3.; Hyundai Motor Company, Namyang-eup, Hwaseong-si, Gyeonggi-do, Republic of Korea.