Numerical Simulation Of Tire Skid Resistance Based On Pavement Macro-texture

As a serious issue faced by the entire transportation industry,traffic safety,especially frequent occurrence of vehicle accidents in rainy days,such as hydroplaning,has been a hot topic in recent research.Through the investigation and analysis of these accidents,it is related to loss of pavement skid resistance.When tire rolls on flooded asphalt pavement with high speed,lift force caused by hydrodynamic pressure will affect the contact interface between tire and pavement.This lift forcewill threats vehicle driving stability and lead hydroplaning.Thus it is required pavement should provide favorable skid resistance to ensure vehicle stability.In this paper,finite element model of tire-fluid-pavement was built based on finite element method and fluid-solid coupling theory,and a new numerical simulation is presented in this paper for the research of tire hydroplaning.Firstly,virtual asphalt pavement model with macro-texture surface was established.Three-dimensional optical scanner(3DS)was used to acquire the three-dimensional topography of the slab specimens.Then the mean profile depth(MPD)calculating method was presented based on MATLAB.In order to acquire the three-dimensional space structure of asphalt pavement,industrial computerized tomography and digital image processing technique were used.Thus the modelling work of asphalt pavement with complex surface texture was accomplished.Secondly,three-dimensional FE model of radial tire with complex pattern was established in ABAQUS.YEOH model was applied to describe the super-elastic mechanical property determined by tensile test on tire tread rubber material.Genetic model and rebar element were used respectively to describe the viscoelasticity of rubber material and anisotropic property of skeleton material in tire.Then virtual tire inflation test and radial stiffness test were conducted to valid the tire model used for hydroplaning analysis.Then the rubber-pavement friction model was deduced based on persson's friction theory.According the fractal features of asphalt pavement,pavement power spectrum was measured adopting segmented variable dimension fractal method.Combining the complex modulus of tire rubber,rubber-pavement friction model was determined.Then a friction subroutine(FRIC)was written in ABAQUS.After that,contact stress distribution and contact area at tire-pavement interface were analyzed.The coMParison pointed out the necessity to establish the rubber-pavement friction model.Forthly,a fluid model was established using Euler elements based on fluid-solid coupling theory.A liquid level tracking technique was applied to simulate free surface of water film.In this process,state equation of water was deduced and the type of fluid-solid coupling was determined,as well as the boundary condition of the fluid model.Finally,the influence of tire inflation pressure,water film thickness,and asphalt pavement surface macro-texture on tire hydroplaning was analyzed.Based on the established tire-fluid-pavement model,it was discovered that initial tire inflation pressure has a positive influence on improving skid resistance of wet pavement.Besides,thicker water film on the pavement leads to smaller critical hydroplaning speed.Moreover,abundant surface macro-texture is favorable in increasing critical tire hydroplaning speed.It is determined that wet friction coefficient increases with the enlargement of MPD value and the decreasing of tire moving speed.Within the same working condition,OGFC owns the highest tire hydroplaning speed,which means it is superior than SMA and AC pavement.This superiority becomes more obvious with the increase of tire moving speed.Based on the research results described in this paper,tire hydroplaning performance of asphalt pavement with different mixture ratio design can be predicted under different conditions.This research provides a significant tool in supervising mixture design of new and recycled pavement.