Study On Vehicle Driving Safety Based On Tire Hydroplaning

With the rapid development of the national economy,the national highway mileage and car ownership continue to grow,and people are paying more and more attentions to traffic safety.According to the investigation and study of traffic accidents,the pavement water film significantly affect the adhesion state between tire and pavement,so as to reduce the vehicle driving stability.Therefore,it is particularly important to explore the maximum speed and the shortest distance of the vehicle under different pavement water film thicknesses and tire wear conditions.In the thesis,the basic principle of tire hydroplaning was analyzed.The theoretical solution of the maximum hydrodynamic pressure on tire was derived under partly hydroplaning condition,and the calculation method of the tire and road adhesion coefficient was determined.Then,the finite element model of tire-road contact was established,and the tire deformation under static loading was analyzed.The reliability of the model was demonstrated by the vertical deformation.The tire deformation characteristics under static loading were extracted.The fluid calculation domain was obtained by Boolean subtraction.The RNG k-ε turbulence model and VOF model were selected.The reliability of the tire hydroplaning model was demonstrate by the NASA hydroplaning velocity.According to the simulation results,the distribution law of water phase and velocity field was studied,and the influence of pattern depth,water film thickness and driving speed on tire hydroplaning was explored.The critical hydroplaning speed under different water film thickness and pattern depth was determined.Finally,the regression equation between road adhesion coefficient and tire pattern depth,water film thickness and driving speed under partly hydroplaning condition was established.On this basis,the double lane change condition was taken as the basic driving demand standard.The Carsim double lane change simulation model of straight and curved lanes was established.The effect of circular curve radius,road superelevation and double lane change method on vehicle driving state was analyzed.According to the comprehensive evaluation results of the path following and driver busyness,it was determined that the road adhesion coefficient was equal to 0.2 and 0.35 as the critical adhesion coefficient when vehicle moved on straight and curved lane.The relationship between the safe speed and the pavement water film thickness and the tire pattern depth was obtained.The dynamic assignment of road adhesion coefficient with vehicle speed was realized by joint simulation of Carsim and Simulink,and the influence of tire pattern depth,water film thickness and initial braking speed on braking distance was studied when the vehicle braked on the flooded road.Combined with driver reaction characteristic,the safe following distance under different pavement water film thicknesses and tire tread depths were obtained.The research results can provide driving safety guidance for driving in rainy days.Combined with the Internet of Things and artificial intelligence technology,the vehicle system can determine the appropriate driving speed and following distance for drivers according to the water film depth,tire wear state and road type,reducing traffic accidents caused by road wet.