Research On Nonlinear Liquid Sloshing Dynamics Of Liquid-filled Heavy Tractor-semitrailer

A great number of liquid freight is transported by tank truck, especially the heavyliquid-filled tractor-semitrailer, which plays an important role in liquid goodstransportation. When suffering braking acceleration or steering maneuvers,liquid-filled tractor-semitrailer will get a huge shock, dramatic changes the quantity ofmotion and moment of momentum suffered by the tank, especially when the tank ispartially filled, under this situation, the liquid is large-scale sloshing. Although thelarge-scale liquid sloshing may last very short time, the sloshing in the tank present theproperty of nonlinearity, it could acute change the inertial force and mass centerposition. So that its risk to the stability of the tank truck is much more than smallwobbles. Liquid sloshing is one of the most significant factors that cause tank truckaccident as turning over. Therefore, it is necessary to study the dynamic characteristicof liquid sloshing and baffles which are created to enhance the stability andcontrollability.In general, the classical method to study the liquid sloshing is simplified anequivalent linearity vibration model. Research results show that the linear systemmodel is useable if the liquid was small wobbles, but when the slosh amplitude over acritical value, the nonlinearity must be considered. The problem with the large scalesloshing has to be solved by numerical method.The object of the present study is taking the heavy tractor semi-trailer tank truckand the study focuses on examining the non-linear dynamic of the liquid sloshing byusing numerical method. A numerical model of the liquid sloshing of the heavy tractorsemi-trailer tank is established based on understanding for liquid sloshing dynamicsand combining VOF and standard equations.The main works of the thesis are as follows:Firstly, a two-degree-of-freedom vibration model of the tank is established byreplacing the equivalent motion of the tank on the road, then, base on vibration model of the tank, a numerical model of the tank liquid slosh dynamic isestablished by using Finite Volume Method in ANSYS.Secondly, a numerical simulation verification experiment of three-dime-nsional liquid sloshing in tank is carried out by the software of FLUENT.The sloshing natural frequency of the sloshing is used to verification withanalytic solution, experimental results and numerical results. The result sho-ws the numerical solution of the fundamental natural frequency of the slos-hing is agreement with analytical solution.Thirdly, a series of the numerical experiments are carried out based on liquidsloshing model under different conditions and cases. The two of the cases includethat tank is suffered braking acceleration and steering maneuvers. The simulatedresults show that the liquid nonlinear sloshing has a serious effort on safety.Moreover, the numerical experiments of the sloshing are carried out with respectto the different liquid property, different filled content under different movingconditions in order to examine the effect of them on the nonlinear dynamicbehavior of large amplitude sloshingFinally, it is established the numerical models of longitudinal liquid-sloshingwith two different types of effective baffle to examining the effectiveness of thebaffles. At the same time, a series of the numerical experiment is carried out andthe numerical results can provide the suggestion about optimization design.