Research On Road Adhesion Coefficient Based On Finite Element Analysis

With the development of the national economy,the vehicle begins to enter the homes of ordinary people,China's car ownership increases significantly.The vehicle brings convenience,but has also brought security problems that cannot be ignored.To improve the safety of vehicles,more and more active safety systems have been used on vehicles.Most active safety systems rely on the adhesion between the tire and the pavement,so on-line real-time estimation of pavement adhesion coefficient has a significant effect on improving the performance of vehicle active safety systems.The current method of estimating the pavement adhesion coefficient can only estimate the state of the road where the vehicle is traveling,but cannot estimate the state of road in front of the vehicle,thus they cannot be used to establish a more accurate safety distance model.In this paper,the influence factors of the road adhesion coefficient and their relationship with the pavement adhesion coefficient are studied by means of finite element simulation,and the relationship model of road adhesion coefficient and its influence factors is proposed.According to the proposed relationship model and the change trend of the road adhesion coefficient with the influence factors,the vehicle can estimate the peak adhesion coefficient of the current traveling road in real time according to the change of the road state and the vehicle state,so as to establish a more accurate safety distance model.First,based on the friction mechanism between tire and road,this paper studies the influence degree of various influence factors on the road adhesion coefficient.On this basis,this paper chooses the fractal dimension of pavement texture,the relative sliding velocity between tread rubber and road,the vertical load of the tire and tire pressure as the main research parameters.Next,in this paper,a contact model between tire and road based is established in ABQAUS.To improve the accuracy of the model,this paper uses the photometric stereo-scopic method to collect pavement texture data.Based on the collected data,a finite element model of pavement texture is built,and the accuracy of the model is verified through comparing the mean texture depth of the road model with the measured one.An elastic constitutive model is introduced to simulate the rubber material in the tire model.Considering the viscoelastic properties of rubber material have a significant impact on the friction properties,the FRIC_COEF user subroutine is used to introduce the empirical formula of rubber friction into the model,so as to establish a more accurate contact model.Then,using the above contact model,this paper takes a large number of simulation analysis with four selected parameters as variables.In order to facilitate the accurate modeling,submitting operations,reading the results and doing post-processing works,a variety of scripting programs have been written to build models,commit operations,and read results automatically,and a software was written to assist in post-processing.Finally,on the basis of the above work,the simulation results are analyzed,and the influence of the above parameters on the road adhesion coefficient is discussed.The current research is limited to the study on the changing trend of road adhesion coefficient with single influence factors,and the research on the interaction between different influence factors and change trend and change rate of road adhesion coefficient under various factors is lack.This paper studies the change trend of the road adhesion coefficient with the influence of a single influence factor,but also the interaction between different influence factors and the change trend and change rate of the road adhesion coefficient in the case of a variety of factors.At the same time,in order to quantify the relationship between the road adhesion coefficient and the above four parameters,the regression results are analyzed by multiple regression analysis,and the relational model between the road adhesion coefficient and them is proposed.