Establishment Of Thermanl Model For The Damping Performance And Simulation For The Flow Field Of The Motorcycle's Shock Absorber

It is an important component for the shock absorber that can ensure vehicles smooth-going, security and reduce the damage for the part of vehicle. With the development of computer, the mathematics model which based on structure paramater is built, and the impact on the performance of shock absorber that every structure parameter do can be analysed by computer simulation. There is a directive significance to the improvement of shock absorber's structure. In this paper, the hydraulic damping mathematics models for front or back shock absorber are established separately, on the others, the internal flow field of cylindric hydraulic shock absorber is simulated. Concrete research as follows:In Chapter One, the research background of this subject and the current research situation for the mathematics model of shock absorber both at home and abroad are introduced. The research meaning and content about this paper are explained.In Chapter Two, the composition and function of motorcycle's hydraulic damping shock absorber are introduced. The forming principle to the hydraulic damping is analysed. The expression is given that fluid flow through the long and thin pipeline, the annular gap and the sharp short hole. The recovered and compressed damping coefficients are discussed and the relevant formulas to damping coefficients are provided. The damping coefficients of shock absorber must match with the vehicle's. Several kinds of hydraulic damping characteristics about shock absorber and the experiment for motorcycle's characteristic are introduced.In Chapter Three, the mathematics models for the front fork hydraulic shock absorber and the back cylindrical hydraulic shock absorber are established separately. The changing law and calculating formulas of the pressure for the front fork shock absorber in the course of restoration and compression is offered. The relations between the amount of fuel-injection and the volume of air which sealed hermetically in the front fork shock absorber is deduced. The model is simulated by MATLAB and compared with the practical testing indicator diagram. The method is proved to be correct and rational. The influence on the hydraulic damping force is discussed when the parameter of the hole diameter or the liquid temperature change.In Chapter Four, the 3D geometry model of cylindrical hydraulic damping shock absorber is established by GAMBIT. The internal flow field is simulated by FLUENT to analyze the distribution in the course of restoration and compression and study the influence on the speed and pressure of internal flow field when the diameter or number of hole change.In Chapter Five, the conclusions are drawn by depicting the whole dissertation, the further research work is prospected.