| Tires are key components of automobiles and important strategic materials for the country,and play a very important role in the development of our national economy.The friction between the tire and the road surface provides the force and moment required for the operation of the car.The friction characteristics of tires are directly related to the handling safety,wear economy and noise of automobiles,which seriously affects the market competitiveness of enterprises and brand benefits,thus becoming a hot spot of concern for major tire enterprises and related experts and scholars.Rubber and product tires are viscoelastic,non-linear,temperature-sensitive and time-varying.The study of rubber friction characteristics is a very complex scientific and engineering problem involving engineering thermodynamics,polymer materials and other disciplines,and is still facing many challenges.In this paper,we focus on the thermal coupling characteristics of rubber friction,from friction mechanism research,development of testing machines to experimental research,theoretical modeling and test verification,forming a more systematic rubber friction test and analysis method.The main research contents are as follows:(1)Rubber friction thermal coupling mechanism research.Focused on the analysis of rubber friction performance of the relevant elements,the analysis of adhesion friction and hysteresis friction in the different factors affecting the trend of change,the temperature sensitivity and viscoelastic behavior of rubber,the study of rubber in the process of motion viscous loss,elucidate the rubber stress field and temperature field interaction of coupling characteristics.(2)Development of a fully-automatic multi-conditions friction testing machine.The experimental machine can realize the rubber friction performance test under the interaction of temperature,slip rate,load,frequency,material formulation,and road condition multiple factors.In addition to the highly automatic control of multiple factors,the basic functions of real-time dynamic data collection and visualization,the tester also solves the problems of self-heating of rubber wheels,adhesion of abrasive chips and friction subsets under high temperature,simulation of various road conditions and pavement replacement.(3)Experimental research and data analysis.The experimental design was carried out by using the self-developed fully-automatic multi-conditions friction testing machine,and the experimental test method was explored and established to study the correlation between three different tread formulations and friction performance under different parameters.The relationship between the friction coefficient and temperature is normally distributed,with the increase of temperature the friction coefficient first elevated and then decreased in a positive distribution trend,to explore the relationship between the friction coefficient and the variables,to provide a research basis for the construction of rubber thermal coupling friction model.(4)Constructing the thermodynamic coupling model of rubber friction.The analytical relationships of rubber friction coefficient on contact pressure,slip velocity and temperature variables were established.The friction coefficient is related to contact pressure and sliding velocity as a power function and to rubber temperature as an exponential function.The model prediction data were compared with the experimental data,and the error was controlled within 5%,which verified the accuracy of the friction model and provided theoretical support for the application of rubber products.(5)The influence of the rubber wheel’s heat generation on the stress distribution is studied by means of simulation,and the changes of the temperature field under different sliding rates are investigated.The rubber wheel rolling process has typical thermal coupling characteristics,and the importance of rubber heat generation and temperature on the study of its friction characteristics is elaborated. |
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