Research On Noise Reduction Performance And Optimization Design Of High-Speed Rail Sound Barrier Based On Fano Resonance Effect

With the continuous improvement and development of the high-speed railway network,the environmental noise caused by the train operation has an increasingly serious impact on the residential areas on both sides of the line.In order to improve the life happiness index of the residents along the line,it is necessary to take scientific and reasonable noise reduction measures to control the problem of noise pollution along the line effectively.The installation of sound barriers in noise-sensitive places along the line has become a feasible way,but the existing high-speed rail sound barriers have problems of poor ventilation performance and heavy weight.At this time,the emergence of acoustic metamaterials provides new ideas for the design of high-speed rail sound barriers.Therefore,this paper takes advantage of the superior acoustic properties of acoustic metamaterials to address this problem and proposes new types of high-speed rail sound barrier design,in order to effectively block the transmission of wheel-rail noise when high-speed trains are running,and at the same time provide new research ideas for environmental noise control along high-speed rail lines.The specific research is mainly carried out from the following aspects:(1)From the perspective of mechanical analogy,the characteristics of Fano resonance are revealed.Based on this,an acoustic meta unit structure composed of spiral channel and hollow channel is proposed,and the sound insulation mechanism,sound insulation performance and sound insulation test are studied.The analysis shows that the meta unit realizes Fano resonance by using the coupling between the discrete state of the acoustic helical structure and the continuous state of the hollow structure,which can efficiently isolate the acoustic energy of a specific frequency band.And the simulation and test results have a high consistency,which verifies the correctness of the meta unit sound insulation calculation model.(2)Based on the meta unit structure,according to the design concepts of combining sound isolation and absorption and arranging and combining meta units of different sizes to widen the sound isolation frequency band,two new types of high-speed rail vertical sound barrier designs are proposed,which are a composite structure sound barrier and a two-meta unit combined sound barrier.The new type of sound barrier can achieve the function of ventilation and light transmission while blocking the incident sound waves from a wide angle,and has the advantages of thin thickness,small weight and good ventilation performance.(3)For two new types of sound barriers,the three-dimensional semi-acoustic barrier models of the composite structure sound barrier and the two meta units combined sound barrier are established respectively.The dynamic response of the sound barrier structure under the combined action of the sound barrier mode,natural wind pressure and fluctuating wind pressure are analyzed,and the strength of the overall structure of the sound barrier is checked.The results show that the designed two sound barriers can ensure the safety under the combined wind load.At the same time,the feasibility of the design is also verified.