Yes
Braking-induced forced vibration, known as brake judder in road vehicles, causes
dissatisfaction to drivers and passengers and also damage and possible early failure in components
and systems. In this paper, the transmission of judder vibration from the point of generation
(the brake friction pair) through the vehicle structure to the driver is investigated for the
particular case of a heavy commercial vehicle. The investigation uses a computer simulation
multi-body dynamic model based on the automatic dynamic analysis of mechanical systems
software to identify any characteristics of the vehicle suspension design that might influence
the vibration transmission from the wheel to the driver.
The model uses a simplified rigid chassis and cab to lump the chassis parameters, so that the
investigation can focus on the front axle/suspension design, which is a beam axle leaf spring
arrangement, and the rear axle/suspension assembly, which is a tandem axle bogie design.
Results from the modelling indicate that brake judder vibration is transmitted to the chassis
of the vehicle through a leaf spring `wind-up¿ mode and a `walking¿ mode associated with the
rear tandem axle. Of particular interest is the longitudinal vibration transmitted through the
chassis, since this creates a direct vibration transmission path to the cab and driver. The simulation
results were compared with the previously published experimental work on the same
design of commercial vehicle, and agreement between the predicted and the measured
vibration characteristics and frequencies was found.
It is concluded that the rear suspension design parameters could affect the transmission of
brake judder vibration to the cab and driver and that a tandem rear axle offers some design
opportunity to control the transmission of brake judder vibrations from the wheel to the cab
and driver. Given that brake judder has so far defied all attempts to eliminate completely
from vehicle brake systems, this is potentially an important opportunity.