With continuous increase of high-speed train operation speed,the vibration and noise caused by rail traffic will seriously affect the sound environment inside the train,and then reduce the ride comfort of passengers.Therefore,the sound insulation design for the source of train noise is very important.Currently,the sound insulation measures can only effectively control the middle and high frequency noises in the car,while the suppression of low frequency noise needs to be further improved.Phononic crystal is a kind of periodic structure material with elastic wave band gap.This structure can form low frequency band gap under the action of local resonance without needing large size,so as to suppress the propagation of elastic wave and play the role of low frequency noise reduction.Based on the phononic crystal periodicity theory,this paper studies the application of phononic crystal in the sound insulation of wood skeleton support layer beneath the floor of vehicle bogie,systematically analyzes the band gap characteristics and sound insulation characteristics of phononic crystal structure and the sound insulation performance of the phononic crystal structure support layer.The results show that the band gap formation frequency band and sound isolation characteristics of the phononic crystal structure can be artificially designed and controlled by changing the structure form and its parameters.Then,based on the phononic crystal theory,the frame structure beneath the floor of high-speed train is designed to be a combination structure of wood skeleton and phonon crystal.It is found that this structure can not only maintain the sound insulation performance of the phonon crystal in the low frequency band of 0-220 Hz and 620-710 Hz,but also greatly improve the sound insulation performance of the frequency band of 220-620 Hz.This structure can retain the support function of the layer structure,as well as improve the sound insulation performance,which has good effectiveness and applicability in the design of high-speed train floors.
关键词
声学/轨道交通车辆/低频噪声控制/声子晶体/带隙特性/隔声特性
Key words
acoustics/rail transit vehicles/low frequency noise control/phononic crystals/band gap characteristics/sound isolation feature
维普
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