In order to characterize hot brake judder from the chassis dynamics point of view, a traditional operational test matrix is performed. In addition to this, more than one hundred accelerations are measured in different critical points of the vehicle chassis. These points are characterized by their tri-dimensional movement using tri-axial accelerometers. The measurement layout selected has been defined in order to determine the main flow of vibration from the wheel-caliper to the body through the knuckle and the sub-frame. Also, the location of sensors at the active and passive side of the sub-frame allow the calculation of the transmissibility though the hard points between the sub-frame and the body. With the objective of exploring braking judder generation and performance, a methodology for judder investigation is proposed. In order to solve judder concerns, a focus on vehicle chassis is needed. In this study, a deep characterization of a judder problem is analysed and a development tool for judder optimization through advanced NVH measurements is consequently presented.

García, Juan J. Ferrer, B. Vitale, A., Squadrani, F. Polo, M. Applus+ IDIADA, Spain; Tonelli, R Faresin, M Mantovani F., Maserati S.p.A, Italy