With The Motor Vehicle Dynamic Response Of Flexible Asphalt Roadbed Under Study

In order to study the influence of the random dynamic load of vehicles on the performance of flexible asphalt pavement, the dynamic model of heavy vehicle was established by SIMPACK and a 3-D finite element analysis (FEA) model of flexible asphalt pavement was established by ANSYS, the dynamic responses of flexible asphalt pavement under random dynamic load was analyzed.A rigid flexible coupling virtual prototype vehicle was established using SIMPACK software. Then a dynamic model of vehicle under road excitation in time domain and spatial domain was established and the vehicle tire normal force and tire normal dynamic load coefficient were computed.A 3-D finite element analysis (FEA) model of flexible asphalt pavement, which is composed of asphalt surface, granular base and cohesive soil subgrade, was established and the loading method of the random dynamic load of vehicles is determined. The dynamic responses characteristics of pavement were studied under condition of B-grade spatial domain pavement and different speeds. The results indicated that, when the vehicle ran over the pavement, there were three abrupt stress changes. The asphalt layer is most easily to produce compaction deformation. The maximum transverse shear stress and the maximum horizontal shear stress occurred at the bound between asphalt layer e and granular base, where it was the most easily to produce shear failure. When the vehicle load is certain, the change of vehicle speed had an obviously impact on the vertical stress of the pavement layers and had a smaller impact on the transverse stress and the horizontal stress. The transverse shear stress increased with the increase of vehicle speed, the horizontal shear stress decreased with the increase of vehicle speed.