Research On Sound Insulation Performance Of Vehicles Based On Phononic Crystals

Social and economic development,people pursue a higher quality of life.Cars are the main tool for people to travel,car riding comfort is an important indicator of the quality of the car evaluation,the car noise has the most direct impact on the comfort of the car ride factors.In order to be more comfortable and have a safe driving and ride environment,improving the market competitiveness of vehicles and vehicle noise reduction processing is becoming increasingly important.The traditional vehicle noise reduction material follows the law of mass action,the heavier the material(the greater the surface density),the better the noise reduction effect will be.In this way,in order to effectively isolate the 600-1200Hz in the low-frequency sound waves,70 dm thick material compartment is needed,which makes it difficult to meet the actual needs.In recent years,a hot topic-phononic crystals are in the field of international science and technology are enough to meet this requirement.In this paper,the characteristics of engine noise under various operating conditions are studied.Combining the band gap characteristic of phononic crystals,selecting the appropriate lattice constant,scattered structure and component material can effectively shield the engine noise,thereby achieving vibration and noise reduction.Then,the uncertain analysis of the obtained phononic crystals is carried out to study the influence of the uncertainty of phononic crystals,such as the material parameters and the structural dimension errors,on the band gap characteristic and noise reduction of the phononic crystals.And providing the basis for the reliability optimization of the late sonar noise reduction performance.The phononic crystals studied in this paper have potential application values on improving the NVH performance of vehicles.The main contents are as follows:(1)Test and analyze engine noise of 500S manufactured by AVIC under all operating conditions.Firstly,collecting the noise signals(time domain)of the engine and noise signal of the drivers’ seat under the condition of idling,accelerating,constant speeding.Then,by employing joint time-domain analysis(auto-power spectrum and cross power spectrum)order analysis method,the noise source and transmission path is ensured,thereby finishing the test and analysis of the noise.(2)Phononic crystals is design and analyzed based on engine noise reduction.Combing the band gap characteristic of phononic crystals,according to the frequency range and peak value,choosing the proper lattice constant,scatter structure and material to design to the cell of the phononic crystals,by employing finite element method to analyze the band gap characteristic and noise reduction.(3)Uncertain analysis of noise reduction of phononic crystals,because of the heterogeneity of phononic crystals,the errors of the manufacturing and the uncertainty of the phononic crystals,such as the material dimensions.The uncertain analysis of phononic crystals is analyzed,thereby analyzing the effects of uncertainties on band gap characteristic and noise reduction.