Structure-borne noise in a passenger car is usually transmitted through multiple and/or multi-dimensional paths. Therefore, identification and control of these transfer paths are effective measures for noise reduction. A power-based transfer path analysis methodology is proposed for this purpose. First, the power flow of each transfer path is estimated with an equivalent-uncoupled-system method based on linear network theory and the Thevenin equivalent theorem. Next, the correlation between the power flow of each transfer path and the sound pressure in the passenger compartment is established; then the contribution of each transfer path is ranked; meanwhile the dominant paths and their key parameters are identified through the equations of power flow calculation. Finally, these key parameters can be analysed and then improved to reduce the structure-borne noise. An illustration of this methodology is given with a passenger car model containing a power plant, three mounts, a compliant car body, and an enclosed acoustic cavity. It is demonstrated that the methodology is effective to analyse and control the structure-borne noise transfer paths.
Exactness of alternative force estimation methods and applications to power flow and transfer path analysis
