The Simulation Research Of Tire Fatigue Life Based On The Virtual Crack Closure Technique

As a composite material composed of cord and rubber,tire has typical fatigue failure characteristics.Tire fatigue failure or puncture is not only a serious threat to the lives of passengers and pedestrians,but also made a negative impact on the traffic.Therefore,the fatigue durability of tires is one of the important factors of automobile safety,and the corresponding standards and regulations are also increasingly strict.At present,the research on tire fatigue durability is more dependent on test method.Due to the high investment and long period of the test method,the cost control and efficiency improvement of research have been seriously affected..In recent years,with the rapid development of computer performance and the continuous improvement of finite element method,it is possible to study fatigue life of tires by numerical analysis.In this paper,the fatigue life simulation of tire is studied based on the thermal effect and Virtual Crack Closure Technique(VCCT).First of all,a free rolling finite element tire model considering of thermal effect was established..The stress and strain of the tire under free rolling condition was obtained by steady-state transmission method,and the heating rate was calculated based on Matlab.Then the heating rate is defined as heat source of each rubber element,and the temperature field of tire is calculated according to thermal boundary conditions and thermal performance parameters of materials.The temperature field is imported into the steady-state transmission model,and the three dimension global model of tire,taking into account thermal effect,can be acquired.Then,a user-defined fatigue fracture element based on VCCT is developed.On the basis of VCCT,combined with the Paris fatigue crack growth rate formula,VCCT fatigue fracture element is developed using the user element subroutine function of ABAQUS.The element can be used to simulate the fatigue crack steady propagation and calculate the energy release rate and the number of fatigue cycles,so as to predict the fatigue life of crack model under cyclic loading.Finally,the fatigue life analysis and evaluation of the tire belt and tire bead are carried out.Combined with the the fatigue damage disease phase analysis of cutting surface of testedtire and the finite element analysis of strain energy density,the location,size and extension direction of crack are determined,and the corresponding local model are established..Then the VCCT fatigue fracture elements are embedded into the crack surface of the local model to control the crack propagation and output energy release rate and fatigue cycles.The comparison of simulation results and the tire drum test results proves the effectiveness of the simulation method.In a word,the simulation analysis method of tire fatigue life based on VCCT can be effectively used in evaluating the belt and bead of tire to improve the optimization design efficiency.