Abstract
At braking, the kinetic energy of a vehicle is converted into heat through friction process. The braking system is one of the most important safety component in a vehicle and is therefore designed to withstand heavy braking conditions such as emergency braking, repeated braking or prolonged braking. However, at low speed braking and moderate brake pressure, such as braking manoeuvres, the brake assembly may be prone to squealing. Despite that brake squeal is not related to any safety issues, it degrades the perception of quality and safety and is, among all Noise Vibration and Harshness (NVH) related phenomena in a passenger car, the one generating the highest warranty costs and customer complains. The present study presents results from brake squeal modelling using Complex Eigenvalue Analysis (CEA) on a complete finite element (FE) brake assembly and NonLinear Transient analysis (NLT) on a simplified FE model. At first, complete brake assembly is modelled and calibrated for two driving conditions. Second, a sensitivity analysis on brake squeal occurrence is performed for two parameters. Third, a modification of the brake disc cooling channel geometry is proposed as a counter measure to the observed squeal frequencies. At last, the possibility of incorporating NLT analysis into actual vehicle projects, as a complement to standard CEA, is explored on a simplified model. The results show that good correspondence can be achieved between experimental measurements and numerical model. Also, numerically developed counter measures can be implemented into completevehicle for verification. At last, NLT analysis as introduced by the simple model, shows abilities to come as a complement to traditional CEA.
KEYWORDS brake disc, brake squeal, complex eigenvalue analysis, explicit dynamic analysis, laboratory experiments, model calibration