Inversion Of Porous Material Parameters And Its Application In Muffler Simulation

As the vehicle's output increases,so does the amount of vehicle ownership.People enjoy the high speed and convenience brought by vehicle.They also face many vehicle-related problems,including vehicle noise problems.At present,measures to control vehicle noise mainly include improving the structure of vehicle and engines to reduce noise sources,installing mufflers to reduce exhaust noise,and adding sound-absorbing materials to eliminate noise.Aluminum foam not only has the advantages of general porous materials,but also has light weight and good sound absorption,which makes it possible to use in mufflers.In order to study the performance of foam aluminum in the muffler,it is necessary to know the acoustic parameters of the foam metal material.However,there are some limitations in measuring the acoustic parameters of porous materials by experimental methods.The idea of parameter inversion provides a new method for obtaining acoustic parameters of porous materials.Details as follows:Firstly,the main forward theoretical model of porous materials is introduced.According to the mathematical characteristics of the theoretical model,genetic algorithm is used to design the method of inverse acoustic parameters.Then,according to the sound absorption coefficient obtained from the impedance tube experiment,the acoustic parameters are reversed and the validity of the inversion method is theoretically verified.Secondly,the main analysis methods of the type of muffler,acoustic performance evaluation index and acoustic performance are introduced.The sound attenuation performance of the main muffler structure was analyzed by theoretical methods,and the sound absorption properties of the three aluminum foams were analyzed by the impedance tube experimental measurement method.Based on their silencing properties,aluminum foam mufflers were designed.Then,the three-dimensional model of aluminum foam muffler is established,the acoustic mesh is divided,boundary conditions are set,and a finite element analysis model capable of solving acoustic pressure information at the entrance and exit of the muffler is established.Finally,the sound pressure amplitude cloud diagram and sound transmission loss curve of foam aluminum muffler are obtained to analyze the acoustic performance of aluminum foam muffler and discuss the influence of some parameters on its acoustic performance,so as to provide reference for engineering application,design and optimization of aluminum foam muffler.