Research On The Prediction Model Of Friction Coefficient Of Asphalt Pavement–Based On The Tire-road Contacting Characteristics

The lack of tire-road coupling friction is one of the main causes of traffic accidents.In order to reduce the occurrence of traffic accidents,scholars in the field of road engineering and vehicle engineering have conducted a large amount of anti-slip performance research from the perspective of road surface macro,micro texture structure and tire tread rubber structure.The results show that the tire-road coupling friction is closely related to road surface texture,load,vehicle speed,slip rate and other parameters.In view of the current situation that the current road friction coefficient test equipment cannot control various related parameters in real time,this paper independently developed and debugged the tire-pavement dynamic friction test system(Tire-Pavement Dynamic Friction Analyzer for short : TDFA,the same below).Based on this system,the tire friction coupling mechanism is researched from two aspects: tire static contact characteristics and tire dynamic friction behavior,and then a friction coefficient prediction model is established.In order to clarify the influence of macro-texture,load,tire pressure and other factors on the static contact characteristics of the tire pavement,three different types of asphalt mixture rut specimens of suspended dense type,skeleton void type,and dense skeleton type were scanned using a laser profile measuring instrument to obtain Macro texture parameters of road table with gradient.Based on the macro texture of the road surface and the pressure film technology,starting from the actual contact area of the tire road and the contact pressure,the single-factor and orthogonal analysis of the tire-road static contact characteristics are carried out.The results show that the load has the greatest influence on the contact area,followed by the macro-texture,and the effect of tire pressure is not significant.When other conditions remain unchanged,the higher the tire pressure or the rougher the macro-texture,the higher the stress concentration.The effect of load on the average pressure and stress concentration is not significant.Based on the analysis of tire-road static contact characteristics,a single factor dynamic friction test was conducted using TDFA.The results show that factors such as slip rate,load,speed,macro-texture,micro-texture,contact area,and contact pressure have significant effects on the friction coefficient.Among them,the load mainly affects the friction coefficient by changing the contact area,and the macro texture mainly changes the friction coefficient by changing the degree of stress concentration,and the impact of the stress concentration degree on the friction coefficient is greater than the impact of the contact area;comprehensive macro texture,micro texture,load,tire pressure,Parameters such as speed are used to design the friction coefficient orthogonal experiment,and the influence degree of each factor on the friction coefficient is ranked,which proves that the correlation between macro texture,micro texture,load,speed and friction coefficient is significant.Therefore,these parameters are included in the friction coefficient prediction model.With the help of MATLAB programming tools,a BP neural network structure is built to complete the establishment of the friction coefficient prediction model,and the prediction accuracy of the model is tested.The results show that this model can effectively predict the friction coefficient under indoor conditions.