| With the development of China’s traffic industry,the density of expressway network increased,a large number of materials through road transport,truck axle major,transport load is far more than the design specification standards,overload situation is serious,heavy truck caused by repeated road structure Fatigue damage.Fatigue life is an important indicator and fundamental basis for pavement design,however,the premise of fatigue life is to analyze the interaction between vehicles and roads,in fact due to the presence of pavement roughness,as well as the coupling vibration of the vehicle and the road,So that the force between the vehicle and the road becomes a random fluctuating load,this is difficult to study the fatigue life.This paper refers to the research results of scholars at home and abroad in recent years,establishment of Coupling Vibration Model for Truck and Asphalt Layered Road,the influence factors of dynamic load factor and body acceleration are analyzed.On this basis,the fatigue life of asphalt pavement is estimated,For the road design to provide a reference.The main contents are as follows:(1)Simulation of pavement roughness using triangular series method,the simulation shows that the road roughness at all levels is related to the change of road direction,driving time and spatial frequency,provides internal incentives for vehicle road coupling systems.The simulated spectrum of the road power spectral density is compared with the original spectrum,and the simulation accuracy of the model is verified.(2)Establishment of 1 + 2 type truck 4 degrees of freedom 1/2 vehicle model and asphalt pavement finite element model,isolation method for vehicles,the vertical vibration equation is obtained by using D’Alembert principle.For asphalt pavement,the vertical vibration equation is obtained by superposition method,according to tire displacement compatibility conditions,get the vehicle road coupling vibration equation,and the Newmark-β algorithm for solving the coupling equations is given.(3)Define vehicle and road parameters,the roughness and roughness velocity vectors of the front and rear wheels are obtained from the road roughness model,establishment of two-dimensional finite element model for modal analysis of asphalt pavement,Get the pavement vibration of the first 10 order natural frequency and damping ratio,through MATLAB prepared to solve the equations of the coupling system,The effects of road roughness,vehicle speed and axle load on dynamic load factor and vehicle acceleration are analyzed.(4)Finally,the dynamic load factor between the vehicle and the road is converted to a constant value,establishment of three-dimensional finite element model by using ABAQUS software,analysis of Dynamic Response of Pavement under Moving Load.On the basis of this,the fatigue life of the pavement is calculated by the tensile strain at the bottom of the pavement,And the fatigue life of different working conditions was studied.(5)The influence of pavement roughness,vehicle speed,axle load and surface modulus on fatigue crack propagation was analyzed by Paris formula according to the stress intensity factor of the crack tip of the asphalt concrete pavement. |
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