Research On A Simplified Method To Calculate Acoustic Pressure Of Three-Dimensional Noise Barrier And Its Acoustic Performance

Road traffic volume has increased rapidly and new roads have been constructed and planned. Noise pollution caused by automobiles has become a serious problem. Noise barrier is an important and simple method to reduce automobile noise. The main purpose of this paper is to research on a simplified method to calculate acoustic pressure of three-dimensional noise barrier and its acoustic performance.In order to predict the noise attenuation of three-dimensional noise barriers, a simplified method is presented to estimate the insertion loss of noise barriers by theoretical approaches. Based on the theory of noise diffraction and acoustic calculation of two dimensional, this method considers the noise diffraction around three-dimensional noise barriers. It can calculate acoustic pressure of one-sided noise barrier, inclined noise barrier and parallel noise barriers. In order to assess the accuracy of this simplified method, comparisons with the results of fast multipole boundary element method are made by examples. The simulation results of analysis show that the acoustic pressure and curve tendency are very good agreement between the frequency range of1/3octave band from20Hz to2000Hz.This paper focuses not only on the analysis of the insertion loss of noise barriers, but also on the effect of noise barriers’locations, geometry shapes, inclinations and sound absorbing materials. The results show that the one-sided upright noise barrier should be placed near the noise source to improve its acoustic performance. The absorbent parallel barrier’s acoustic performance is much better than rigid noise barrier.It also provides a way to design the totally enclosed noise barriers according to the acoustic requirements. Comparisons are made with different stiffener plates and boundary conditions of natural frequency. The simulation results of analysis show that the transmission loss can meet the noise reduction requirements on acoustical design.Compared with other numerical methods, this method is much easier. It has reference value for the research and design for three-dimensional noise barriers. And also some new ideas are presented to optimize the design of noise barriers.