The Lower Interior Noise Characteristic Analysis And Optimization Of Passenger Car

With the rapid development of modern automobile industry and people’s livingstandards gradually improved, Customer comfort cars have become increasinglydemanding, NVH performance of the car is an important indicator to evaluate theperformance of the car comfortable, therefore, analyzing and improving NVHperformance of vehicles has important practical significance. Vehicle Interior Noise isan important impact on the vehicle NVH performance, Especially by the acousticcavity and the body structure of the low-frequency coupling structure brings noise,Expressions of the low-frequency roar, Expressions of the low-frequency roar topassengers in the car bring great annoyance. Today, how to in automotivedevelopment process for automotive NVH design, Effectively reducing noise andvibration levels inside the vehicle, Improve passenger comfort, Has become a focus ofthe automotives industry research.In this paper, to a passenger car models for the study, Analysis of structuraldynamic characteristics of the car body and interior acoustic response characteristics.The main research contents are:1. The vehicle body modal analysis: To establish the finite element mesh modelof passenger car body structure and on the free modal analysis, Understand thedynamic characteristics of BIW and Trimmed body structure; White body model formodal test, By modal test results and simulation results are compared, Both the valueof the same natural frequency modes maximum difference of5.7%, Within the error,verify the accuracy of simulation modeling.2. Vehicle Interior acoustic analysis: Based on the finite element body structuremodel to build Vehicle Interior acoustic cavity and freedom to modal analysis,Understanding of characteristics of the sound pressure distribution acoustic cavity;Establish acoustic cavity and body structure coupling model, based on modalfrequency method, In the front and rear suspension attachment point of The vehiclebody applied to the unit noise excitation, Obtain Vehicle Interior noise transferfunction of the reference point, At the same time can get on the car reference pointcontribution to the larger sensitive path and peak frequency; And to The vehicle bodystructure of the noise transfer function of experimental test, Get the same result andsimulation analysis and comparison.3. Acoustic panels contribution analysis and structural optimization: Acousticcavity outer boundary is divided into13panels, Through to the reference point noisecontribution to the larger sensitive path and peak frequency in the panel contributionanalysis, Calculate the at the peak frequency, acoustic cavity each section of theborder interior noise contribution, Obtained Vehicle Interior Noise plays a majorpositive contribution plate. For noise peak sound pressure response, Combinationplates contribution analysis results and the actual situation, Comprehensive structuralimprovements proposed, thickness parameter optimization and damper attached to avariety of optimization, The body structure optimization measures taken after thenoise transfer function analysis, After the simulation results show that: After optimization the car Interior noise in response to the reference point has beeneffectively reduced.