Dynamic Loads Analysis Of Four-Axle Semi-Trailer On Undulate Pavement

Vehicles occur vibrations in the course of driving on the uneven pavement, which lead the wheels on the road to produce additional dynamic load.This load is constantly changing load, not equivalent to static load, would hasten the pavement destruction, while the pavement roughness degraded, would make the wheels on the road to increase the additional dynamic load.This vicious circle produces a great influence on the use performance and life expectancy of pavement.However, traffic have developed along the high speed and over loading line as the highway network gradually in the dense, which increase the speed of pavement destruction, lead to the service life of pavement is far less the designed life, result in the early damage of pavement. In addition, the traffic will also reduce it’s life, if the dynamic load too large.This problem poses new requirements for the safety reliability and economy durability of road structure and vehicle design.Combining the vehicle with the road to analysis the interaction between them, has become a hot topic studied by vehicle dynamics and road.Based on the coupling effect between vehicle and road, the reason caused the vehicles on the road to produce dynamic load is analyzed by theoretical deduction and numerical calculation. Regarding the heavy truck as the research subject, a multi-body dynamics model of four-axle semi-trailer is built by simulation software ADAMS/Car, and the pavement surface was imitated by using sine curve, the road file was compiled based on the actual measurement result of Qijiang-Wansheng highway pavement evenness. Coupling of vehicle and road the simulative analysis on the vehicle dynamic loads of wheels under different road status, vehicle speed and load has been conducted, the simulation results show the three factors all produce a great influence on the vehicle dynamic loads. When wavelength of road surface is fixed, the vehicle vibrating frequency increases with amplitude rise, the more additional dynamic load will get, only if the speed reached a certain value could the vehicle vibrating frequency is similar with excitation frequency of uneven pavement, the vehicle-road coupled resonance, the most additional dynamic load will get. When amplitude of road surface is fixed, the vehicle vibrating frequency decreases with wavelength rise, the less additional dynamic load will get. When road excitation is fixed, the dynamic load coefficient of wheels overall show a rising trend with speed increases.The dynamic load increases with vehicle load rise, and the rate is very large.Based on the analysis of the simulation results, some suggestions are proposed to control the early damage of high-class asphalt pavement:the destructive action of dynamic load on pavement should be taken into account in pavement structure design, the pavement wavelength and amplitude should be controlled to improve the pavement smoothness; in traffic, overloading should be strictly prohibited, and the vehicle speed should be strictly restricted on the poor smoothness roads.