| The vehicle load is regarded as static load in the road design methods in our countryand other countries of the world. It is suitable when the load is not too large and thevehicle speed is not too fast. With the development of high speed and heavy dutytransportation, the vehicle dynamic load caused by road roughness increase dramatically.Difference between static load and vehicle dynamic load is growing, the dynamiccharacteristic of road is also far from static characteristic. The road damage caused byvehicle dynamical force leads to vehicle vibration increase greatly, which influencevehicle’s driving safety and riding comfort. Therefore, the vehicle and road are interactedand coupled, vehicle model and road model are linked as a interaction system in thispaper, further study of the vehicle dynamic load and dynamic responses of the road underthe heavy vehicle has very important realistic meanings.As tire deformation is larger than pavement deformation, vehicle, tire and road forma weak coupling system. This article mainly research contents are as follows:(1) Research on the vehicle dynamic load. The time domain model of different level roadand a quarter car model with two degrees of freedom are built and used to analysis thevehicle dynamic load in frequency domain. The effects of vehicle speed,load, tirestiffness and suspension damping parameter on dynamic load coefficient are investigated.The result shows that the dynamic load generated by heavy duty vehicle is primarilydistributed in the low frequency region and decreasing tire stiffness or increasing thesuspension damping can effectively reduce the vehicle dynamic load.(2) Dynamics analysis on2d car-road system. A Bernoulli-Euler beam on Kelvinviscoelastic foundation is put forward to model pavement structure and a car-road systemis established. Nonlinear suspension damping and nonlinear tire are studied. Vehicledifferential equation are analyzed in theory by the average method, the dynamicresponses of road structure are researched by the constant variation method. Based on thecar-road system, dynamic responses of vehicle and pavement are researched by Newmark numerical method.(3) Dynamics simulation of the vehicle-cement concrete pavement system. A sevendegree of freedom vehicle-cement concrete pavement system is established by linking thevehicle and infinite thin plate on Kelvin viscoelastic foundation. The structural dynamicresponses of pavement are researched numerically by different speed, tire stiffness, load,foundation modulus and the thickness of pavement. The simulation results indicate that the vehicle-cement concrete pavement system has certain validity and solidifying thefoundation, increasing the pavement thickness and reducing tire stiffness and load andsuitable vehicle speed can reduce the deformation of the road.(4) Dynamics response and fatigue failure of semi-rigid asphalt pavement by heavy dutyautomobile. According to the asphalt pavement layer system theory, ANSYS model ofthe pavement structure is established. The stress and strain of road structure are analyzedunder moving load. Through the analysis of road crack, fatigue failure of road is alsostudied and the fatigue life is predicted by bending tensile strain of the bottom ofpavement.(5) Study on robustH2/H guaranteed cost control for reducing vehicle dynamic forcesof vehicle active suspension. In order to reduce the road damage, the suspension activecontrol technology is used. Vehicle active suspension control problem is considered as adisturbance attenuation problem with time-domain hard constraints where theH2norm isadapted to minimize the output performance of tire dynamic load, theH norm is used tosatisfy requirements of the suspension travel and body acceleration. An optimal robustguaranteed cost control law is proposed and the simulation result shows that the methodis effective and to reduce tire dynamic impact obviously. |
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