Brake noise tests on dynamometers and vehicles are exposed to significant result variability. This deserves attention firstly, because noise tests are consuming a big proportion of total brake development time and costs.
Secondly, at a certain engineered NVH level of a brake system, reducing result variability (also in the customers' vehicles) is a development target itself. So a key question is how to reduce test result variability.
This paper discusses the meaning of systematic and random variability in brake NVH development and gives examples where randomness has to be taken into consideration in project practice.
A pragmatic approach worked out within Expertenkreis Bremsgeräusche (EKB / Brake Noise Experts Group) is shown to document and identify influencing parameters. The paper also wants to exploit the potential of related EKB specifications.
Thomas, Claus - Dr. Ing. h.c. F. Porsche AG