Road Noise Analysis Using Component TPA and FBS with Vehicle Component Modifications

Road noise caused by road excitation is a critical factor for vehicle NVH (Noise, Vibration, and Harshness) performance. However, assessing the individual contribution of components, particularly bushings, to NVH performance is generally challenging, as automobiles are composed of numerous interconnected parts. This study describes the application of Component Transfer Path Analysis (CTPA) on a full vehicle to provide insights into improving NVH performance. With the aid of Virtual Point Transformation (VPT), blocked forces are determined at the wheel hubs; afterward, a TPA is carried out. As blocked forces at the wheel hub are independent of the vehicle dynamics, these forces can be used in simulations of modified vehicle components. These results allow for the estimation of vehicle road noise. To simulate changes in vehicle components, including wheel/tire and mount bushings, Frequency-Based Substructuring (FBS) is used to modify the vehicle setup in a simulation model. In this process, analytic springs were added in parallel to the actual rubber mounts, which were also measured using VPT on the actual vehicle. These springs simulate positive or negative changes in stiffness, allowing the study of how changes in the rubber mounts affect the vehicle's NVH performance. In this study, a sensitivity analysis was conducted using the FBS model to observe changes in road noise resulting from variations in bushing stiffness and blocked force. Based on the results of this analysis, the optimal combination of components was proposed for reducing the road noise. This approach provides an efficient and accurate method for analyzing the effects of rubber mount modifications on NVH performance.