Research On Liquid Sloshing Non-linear Model And Driving Stability Of Partially-filled Tank Trucks

Tank truck is widely used in the transport of liquid dangerous goods, at the same time, tank truck’s traffic safety problems are rising in the transportation. Especially in the process of emergency braking, high-speed corners, or emergency avoidance, liquid are great sloshing in the tank of partially-filled tank trucks, traffic accidents may be caused, even in rollover, fire, explosion, environment pollution and mass poisoning and other serious consequences.Due to high risk caused by real tank truck test, lead to the test data of extreme conditions are difficult to collect and make impact on the driving stability of tank truck, mostly using numerical model simulation method to research, if test method is combined with numerical simulation model, can be more comprehensive analysis of liquid sloshing in the tank impacting on the driving stability of tank truck. This paper set up liquid sloshing simulation test bench, more intuitive and safety observation liquid sloshing phenomenon, summarizes rules of its motion; Using the mechanical equivalent principle and similarity theory, the equivalent mechanical model was established, to mechanical equivalent substitution of fluid motion, describes liquid sloshing linear motion in the tank; Nonlinear dynamic model is established, describes liquid sloshing non-linear motion in the tank; By optimizing algorithm optimize the impact factors of liquid in the tank, get the better roll stability of tank truck’s tank size; The impact on roll stability of tank truck by liquid sloshing in the tank, respectively from the liquid impact parameters and relevant to the lateral acceleration limitation of tank truck, two aspects were analyzed. Therefore, this paper use experiment method, the equivalent mechanical model, the nonlinear dynamics theory, the optimization algorithm and vehicle system dynamics theory, liquid sloshing in the tank of partially-filled tank trucks is described and researched. Finally, this paper realizes to test method combining the numerical simulation model to analyze the driving stability of the tank truck. The main contents are as following:(1) The analysis of liquid movement characteristics and the impact factors. Through the analysis of tank liquid impact phenomenon, built liquid sloshing simulation test bench. Simulation test bench is designed, braking and steering process simulation tests have been carried out, extract the impact factors of liquid sloshing. The results revealed that, shape and size of tank liquid impact, liquid fill level and external excitation frequency and other factors are the impact factors of liquid sloshing; Determine cross section shape of tank for the smaller liquid sloshing force.(2) Construct linear model of liquid sloshing in the tank. Using Quasi-Static model, C.G. motion curve was used to solve. Using the mechanical equivalent principle and the similarity principle, liquid sloshing equivalent mechanical model(quality- spring model and the pendulum model) are established. Using quality-spring model, the five different size proportion of oval cross-section numerical simulation experiment was carried out of tank, obtained good lateral stability of tank for oval cross section size of tank. Liquid linear sloshing motion under small vibration, divides the liquid natural sloshing frequency range, numerical simulation experiment was carried out, comparing the instantaneous maximum impact data, the two equivalent mechanical model is obtained corresponding fluid sloshing frequency range.(3) Construct non-linear model of liquid sloshing in the tank. Using Lagrange equation, the non-linear model of liquid sloshing is establish, clear about the vibration frequency of nonlinear dynamics model and the calculation method of related parameters. Nonlinear dynamic model make numerical simulation analysis, clear about liquid the impact of the nonlinear motion change rule. Through simulated test data compared with nonlinear dynamic model, has been clear about the nonlinear dynamic model to describe the accuracy and the deviation of the tank liquid nonlinear phenomenon.(4) Optimization of liquid sloshing impact factors. Tank truck lateral response dynamics model is established, use the liquid sloshing equivalent mechanical model for fluid-solid dynamic coupling, fluid-solid dynamic coupling model of tank truck is built. Using the optimization algorithm to optimized fluid-solid dynamic coupling model, as a liquid mass center height and overturning moment as optimization objective, observe the optimal section size of the oval tanks. Rollover limitation model of tank truck is established, the lateral acceleration ay limitation numerical model is determined.