Numerical Simulation Study Of Four-point Bending Fatigue Characteristics Of Asphalt Mixture

In recent years,with the increase of traffic flow,the anti-fatigue characteristics of roads are facing increasing challenges.How to accurately predict the road fatigue life and improve the road fatigue resistance has become more and higher.This thesis studies the fatigue life of asphalt mixture road.Phenomenology method,fracture mechanics method and energy dissipation method are most commonly used in the research methods of fatigue life of asphalt mixture.Combined with these three methods in the four-point bending fatigue test,the research results of phenomenology,fracture mechanics and energy dissipation method can be obtained in different parameter Settings,and it has the advantages of simple test,easy operation and small cost,so it is most commonly used in studying the fatigue performance of asphalt mixture.However,with the development of the road,the fatigue life obtained by the four-point bending fatigue test has become more and more wrong with the fatigue life of the actual road surface,which cannot meet the current requirements of the road.Therefore,a large number of scholars have studied how to improve the accurate prediction of road life.It is generally believed that the research from indoor test to simulation can promote the development of road fatigue performance.It is found that the discrete element method has a good effect on the problem of numerical simulation,but how to apply the discrete element method to the fatigue life of asphalt mixture pavement is a problem worth studying.Based on four-point bending fatigue test,using PFC 3 D software.By controlling the strain of the four-point bending fatigue test,we construct the real-time load model of the indoor trabecular beam,and write the numerical simulation load with the real-time load model.The stress and strain are analyzed in the numerical simulation test,and the numerical simulation model of the four-point bending fatigue test is obtained,which is combined with the four-point bending fatigue test to study the relationship between the two.Finally,the fatigue life of the small accelerated fatigue test and four-point bending fatigue test is corrected.The results show that the simulated stress and strain changes are consistent with the changes of the indoor test,and it is feasible to simulate the discrete element PFC 3 D.The numerical simulation stress and strain curve model can well describe the rule of asphalt mixture.The stress and strain curve model is divided into two stages before and after failure.Analysis between numerical simulation and four-point bending fatigue test,establish a linear model between strain and fatigue life.Finally,the results of the simulation test are corrected and the correction coefficient are obtained.Numerical simulation can replace the indoor four-point bending fatigue test to some extent.