Power Flow Analysis Of Vehicle-road Coupled Vibration System

Vehicle-road coupling dynamics is not only an important research direction which is of practical engineering significance, but also a hotspot research question.While currently, researchers mainly focus on building a precise vehicle-road coupling model, and use all sorts of calculating method to study the deformation and stress of road, also conduct some researches on the velocity and acceleration of the vehicle.Researches also were conducted in this thesis, adopting a newly developed method,namely the power flow method, it can study the transmission and transfer of energy in vehicle-road coupling system.The main research contents are as follows:(1) The transmission and transfer in complicated linear vibration system,as well as the main equation and calculation method of power flow was analyzed.(2) A single DOF nonlinear vehicle model was built and its system equations was studied. Harmonic balance method was adopted to analyze the amplitude-frequency response curves. Through conducting a Nondimensionalization procedure,and using the average method, system response stabilization was discussed. Based on the power flow method, power flow as well as the maximum kinetic energy equation of vehicle were derived. Using numerical approach, approximate solution and numerical solution were compared. As a main task of the third chapter, the effect of linear stiffness, nonlinear stiffness and damped coefficient on input power flow and the maximum kinetic energy of vehicle were discussed(3) A single DOF nonlinear vehicle-road coupling model and two DOF nonlinear vehicle-road coupling model were built respectively also the coupling equations were obtained. A discretization process was conducted upon road equation, meanwhile harmonic balance method was used to tackle the coupling equations. The energy equations from road excitation to vehicle, from vehicle tire to road as well as the maximum kinetic energy of vehicle were formulated. The energy relationship between vehicle, tire and road were obtained. Aim at decreasing the input power flowand the maximum kinetic energy of vehicle, system parameters were optimized by using numerical approach. The result provided in this thesis demonstrated that the power flow method could reveale the transmission and transfer of system energy, and it can also provided a reference for choice of parameters in vehicle-road system.