Design And Simulation Of A New Road Sound Barrier

With the accelerated modernization process of China,the road traffic network is more and more developed.The number of motor vehicles presents an explosive growth trend,but the traffic noise pollution problem is more and more serious.As remarkable effect and low price,the sound barrier has become the most suitable means to prevent and control traffic noise pollution.Nowadays the awareness of noise pollution control is becoming stronger and stronger,however,most of the actual sound barriers exist serious lack of insertion loss,and the effect of noise reduction needs to be further improved.The main reason is that the sound insulation performance of the screen body is insufficient and the attenuation of the diffraction at the top is too small.Therefore,it is of great significance to design a sound barrier with superior noise reduction performance.From the three points of sound insulation,absorption and diffraction,we have designed the screen body and the top structure of noise barrier respectively,and then verified its acoustic performance by numerical simulation.At the same time,combining the latest research of sound barrier and sonic crystal,a new sound barrier based on sonic crystal is designed.The main work can be summed up as follows:(1)The sound barrier screen body is designed and simulated from two aspects of sound absorption and insulation.The upper and lower portions of the screen body are designed into three layers of micro-perforated plate,sound absorbing material and steel plate.And the middle of the screen body is made up of a double-layer transparent plate.By means of numerical simulation,the sound insulation is proved fully meet the design requirements.The structure has good sound absorption and insulation performance on low,medium and high frequency sound waves.It overcomes the weakness of traditional screen bodies for sound insulation on low and medium frequency sound waves.(2)The top structure of the sound barrier is designed and simulated from the point of sound diffraction.According to the theory of Schroeder diffuser,the maximum length sequence(MLS)diffuser,prime root diffuser(PRD)and the quadratic residue diffuser(QRD)at the top of the sound barrier have been designed.It is proved by numerical simulation that the insertion loss of the three structures is obviously higher than that of the T type sound barrier with the same size.The three structures is simple and can effectively improve diffraction noise attenuation withoutany extra cost.It provides a practical solution for improving the sound attenuation of the sound barrier diffraction,and has excellent practicability.At the same time,we set up several simulation models of noise barriers for QRD sequences,so as to study the influence of different structural parameters on insertion loss.It is of great reference value to provide guidance for reasonable design of the top structure of QRD sequences.(3)A new type of sonic crystal sound barrier is designed and simulated.According to the theory of Bragg sonic crystal band gap,we design a multiphenomena scatter array sound barrier based on multiple scattering as the core while taking into account the absorption modes such as resonance absorption and porous material.According to the simulation results,the top structure of sonic crystal has greatly increased the insertion loss of sound barrier.The sound barrier of sonic crystal interconnects in space and provides a new solution for solving the disadvantages of traditional sound barrier,such as geographical isolation and landscape separation.At the same time,the sound barrier is a unique scenery line with good aesthetic appreciation with broad development potential and application prospect.