Study On Identification Of Interior Noise Source Based On Operational Measurement

The NVH performance has become one of important factors affecting consumer choosing which kind of vehicle.From the last seventies to now,people's demand for ride comfort were increasing significant with improvement of people's living standard in our country.A large amount of efforts have been invested to development of new technologies of interior noise reduction by domestic auto manufacturers.There are four aspects about interior noise controlling,which are NVH test,evaluation,source identification and improvement measure.Through years of growth,Transfer path analysis(TPA)has been an important method in automobile source identification.The traditional TPA techniques identify the transfer path by disassembling system and isolating each path,which studies the relationship between source and response.This method can obtain detailed transmission characteristics of system,but it will be time-consuming and the boundary conditions are not correct anymore.In this paper,an operational transfer path analysis(OTPA)technique based on partial singular valued decomposition(PSVD)was used.A multi-input/single-output system based on response-response was established.The number and location of sources were identified by singular valued decomposition and partial singular valued decomposition.The contribution of sources were calculated by output prediction theory.The variation of interior noise was predicted after some source changed.The work in this paper shown that interior noise source of vehicle prototypes mainly contains dash board area,front roof,middle window and rear floor.Vibration in X direction of right engine mounting and Y direction of rear axle made the greatest contribution to interior noise,so they should be regarded as primary correction target.Experiment verified that the analysis method and computational process in this paper is correct and accurate,which is believable to guide NVH improvement.