Study On Acoustic Structure And Noise Reduction Performance Of Periodic Array Phonon Crystal Barrier For Expressway

The sound barrier is the most effective control method to address the issue of highway noise contamination.Nevertheless,the traditional sound barrier is most of uniform dielectric structure,and noise reduction performance is relevant to the surface density of materials.Increasing the surface density of materials will increase the material cost and the construction difficulty,which limits the use of traditional sound insulation materials.The periodic array phonon crystal structure provides a new notion for traffic noise control.The band gap characteristic of the periodic structure of phonon crystals is of great significance in preventing the propagation of elastic waves,but current domestic and foreign research attach great importance to the study of the theory of the high frequency band gap because of the few study in actual engineering applications.The application of the low frequency band gap of the phonon crystal periodic structure in the noise control is urgently needed to carry out creative work in its low frequency band gap mechanism and the applied exploration.Therefore,aiming at the low spectral characteristics of highway noise,the application of phonon crystal theory to acoustic barrier acoustic design research is of great significance for noise control.Based on the principle of elastic and bandgap,this study clarifies the main noise frequency band range of phonon crystal sound barrier design through the field measurement and research on main noise reduction frequency band of expressway.By using the finite element software COMSOL Multiphysics,the sound barrier band gap characteristics and acoustic structure of two-dimensional gas-solid periodic phonon crystals are simulated and calculated.In this way,the influence of scattering structure parameters and material parameters of scatterers on phonon crystal band gap range of phonon crystals and the effects on reducing the frequency noise are analyzed.The feasibility of using the abandoned corrugated beam guardrail column removed by rebuilding and expanding the road as the scatterers of the phonon crystal type sound barrier is verified.The finite element simulation and indoor semi-anechoic fluctuation experiment represent that:(1)The band gap width of gas-solid two-dimensional periodic phonon crystal is mainly determined by the structural parameters of its phonon crystal,and the material of the scatterer have little effect on the band gap;(2)In the range of main noise frequency band of the typical expressway in the frequency range of 400Hz-800Hz,the recycled waste wave beam guardrail column is used as the scatterer material.The two-dimensional air-hollow steel plum blossom column periodic phonon crystal type sound barrier noise reduction effect can reach 15dB and above;(3)In the indoor semi-sounding experiment,for the highway with the main noise frequency range of 400Hz-800Hz,the plume-shaped column combined phonon crystal type sound barrier has the best noise reduction effect,the average noise reduction is 27.9 dB(A),and the maximum insertion loss is 22.6.dB,Glass wool filled slotted steel column combined with phonon crystal type sound barrier,the average noise reduction is 24.3dB(A),and the maximum insertion loss is 19.5dB;(4)It is feasible to recycle the discarded corrugated beam guardrail column for the phonon crystal type sound barrier design,and the effects on reducing the frequency noise are indicated.In comparison with the sound barrier of traditional materials,the cost is reduced by 40-70%,and the integration of conceptual technology innovation and recycling of waste resources can be realized.