Research And Optimization Of Pavement Surface Texture With Low Noise Function

With the development of human society and economy,traffic noise pollution is gradually becoming a serious environmental problem,which not only seriously damages people's physical and mental health,but also restricts the economic value of real estate near the noise source.Traffic noise is caused by the combination of aerodynamic effect,vehicle power system(exhaust and engine)and the interaction between tires and the road surface.With the technological innovation of the automobile industry,the noise of the vehicle power system has been effectively controlled,and tire/road noise has become the main source of traffic noise.Studies have shown that tire/road noise is mainly composed of tire vibration noise and aerodynamic noise.The main factors influencing tire/road noise are surface texture and void ratio.The surface texture of the road surface mainly affects the generation of tire vibration noise,and the road void ratio mainly affects the generation of air pump noise and the transmission of tire/road noise.Therefore,the optimization of surface texture and void ratio should be taken as the design direction of low-noise pavement.Considering that the noise reduction effect of porous pavement has been studied extensively,Meanwhile,the high cost and short life limit the application range of porous pavement.From this perspective,it has broader significance to study the influence of surface texture on traffic noise.With the development of science and technology,the road industry has been able to process the surface texture into the desired profile morphology through surface treatment(program-controlled precision milling,etc.).However,due to the simplification of actual surface texture and indoor simulation conditions,the relationship between surface texture and road noise cannot be comprehensively investigated and verified,especially the impact of a single variable of surface texture on road noise.Thus it is impossible to obtain an optimized ideal surface texture of low-noise pavement to guide the road surface treatment.In view of this,from the perspective of geometric evaluation of pavement surface profile,this paper used finite element simulation and correlation analysis methods to investigate the relationship between the indicators of surface texture and road noise,and establish an empirical model of vibration noise based on surface texture geometrical parameters.Meanwhile,based on the BP neural network model and optimization method,the research on the surface texture design method based on target noise was carried out,and the forward prediction and reverse design of surface texture and noise level are realized.Then,3D printing technology and noise test method based on indoor acceleration loading system were used to verify the accuracy of the vibration noise prediction model and surface texture design method.Finally,a single-layer structure was used to carry out low-noise functional design.The main research of this paper was as follows:(1)From the perspective of the geometric index of the surface profile curve,the geometric parameters of the surface texture longitudinal depth,horizontal distribution,and spatial morphology are summarized.The linear laser scanner was used to extract the surface profile curve of the asphalt concrete pavement,and the geometric parameters of the surface texture were calculated.At the same time,the tire/road relative motion model was established to extract the tire vibration displacement curve,and the tire-air-road coupled noise model was constructed to calculate the time domain and frequency domain noise levels under the excitation of two-dimensional profile.Systematic research was carried out to investigate the correlation between surface texture geometric characterization parameters and vibration noise,the influence mechanism of texture parameters on total noise,low-frequency noise and high-frequency noise was analyzed,and the importance of surface texture geometric parameters related to vibration noise was analyzed.Through the principal component-stepwise regression method,an empirical model of vibration noise based on surface texture geometric parameters was established to achieve prediction of noise level based on road texture.(2)In order to achieve the accurate expression of profile curve,The Fourier series was adopted to fit the surface profile curve,and it was found that in the research on noise performance correlation of the surface contour,the Fourier series fitting goodness R2?0.9 of the profile curve could meet the precision requirements.Then,the BP neural network was used to establish the nonlinear function model of the Fourier coefficient of profile and the noise level,the optimized objective function based on non-linear function was framed.Finally,the interior point method-particle swarm hybrid algorithm was used to get the optimal solution of Fourier Coefficient of profile under the target noise,so as to realize the reverse design of the surface texture.(3)The line laser scanner was used to extract the surface profile curve of the pavement,and based on the digital image stitching and registration algorithm,the pavement profile model of the real road was reconstructed.Two methods were used to directionally generate surface profile:(1)Based on the prediction model of vibration noise,the surface profile database related to the vibration noise was established,then the target profile curve were randomly selected and combined into the surface profile surface;(2)The surface texture design method was used to generate the profile curve under the desired noise,then the target profile curve were randomly combined into the surface profile.3D printing technology is used to copy and customize the surface profile,and the texture level index is used to evaluate printing quality of the texture on the macro and micro scale.The results show that 3D printing has high reproducibility for most macro-textures,but it is difficult to reproduce micro-textures,and it is verified that the application of 3D printing technology in the field of surface texture customization is feasible.Finally,based on the noise test method of the main driving wheel-type road material acceleration loading system,the tire/road noise test and evaluation of the real specimens,duplicate specimens,and customized specimens were performed to verify the accuracy of the vibration noise prediction model and the surface texture design method as well as the feasibility of 3D printing technology in the field of surface texture customization.(4)Refer to the structure of the chip seal,the single-layer aggregate structure was adopted to design the low-noise functional layer.The aggregate particles with corresponding characteristics were generated by MATLAB software,and combined into a single-layer structure randomly,and the surface profile of the single-layer structure was extracted to calculate its vibration noise level.Taking the design parameters such as particle size,angularity and gradation of the aggregate as influencing factors,the research showed the single-layer structure composed of coarse-grained(9.5-13.2mm),low angularity(roundness value 1.0-1.3),and single-grain aggregate exhibits lower vibration noise level and can be applied to low-noise single-layer structure design.