Linearized Simulative Approach for the Investigation of a Friction-Induced Low-Frequency Brake Moan Oscillation Phenomenon Within Passenger Vehicle Front Axles

Noise, Vibration and Harshness phenomena regarding a passenger vehicle’s brake and suspension system can imply a reduced sense of quality as well as significant warranty costs. In contrast to well-researched mid- to highfrequency
brake squeal, low-frequency vibrations have gained popularity only most recently. Brake moan is one of these effects, featuring frequencies from 350-600 Hz. Among others, independent wheel suspension systems at the front axle can exhibit moan-related oscillations. Here, evaluations imply high familiarity to disk brake squeal, which can be explained by a coupling of different eigenmodes of suspension and brake system, induced by the frictional contact between disk and pads. Consequently, simulation techniques used for squeal evaluation should be applicable for moan phenomena too. Hence, the linearized approach of the Complex Eigenvalue Analysis was investigated for a Finite Element model of a vehicle’s front corner. Parameter variations within a relevant operating range were performed for two different rim designs. A validation based on experimental tests reveals the simulative method’s ability to predict the eigenfrequency of characteristic torsional rim oscillations. However, stability was computed divergent to the systems’ real-life behaviors: Further examination and correct implementation of sensitive parameters seem necessary for a predictive application of this linearized, simulative approach.