Dynamic Pressure Research On Railway Truck From Granular Or Fluid Load

In China, the railway transportation is an important part in national transportation net, which is difficult to be substituted by other transportation tools. In addition, it greatly improves the economics development of our country. As the carried load of goods increase and the train speed rise, the operating safety of railway will be more challenged. In the dissertation, the gondola train and tank train is studied. The dynamic force produced by the granule in the gondola train and the fluid in tank train are analyzed; it should provide useful data for setting reasonable operating parameter and for designing and manufacturing high quality train. The main research results are as following: On the foundation of classic initiative soil pressure level analysis method, the theory model is provide which computing the granular goods effects on the wall of gondola train; also the computing program is provide to solve the theory model. The computing results show that: the granular force distributed on the wall of gondola has the shape of half-arch. Especially when it nears to the goods surface, the different is larger between the theory model and the classic initiative model. In order to verify the model right, the finite element model (FEM) is established. The FEM simulating results shows that: the force distribution from the theory model is same as that of the FEM results, the details are as following: when the friction angle between the train wall and the granular goods 8 increase, the initiative pressure decrease, and its act position become rise. While the friction angle of granular goodsφrise, he initiative pressure decrease, and its act position become decent. The sand and the clay have the same result of force distribution on the wall of gondola. Theθ_C value reflects the shape of cure surface of fracture. The smaller theθ_c is, the sharper the curve surface of fracture is, that is more close to the straight line. Asδgrows,θ_c will rise, and as theφraise, theθ_c will decrease.About the dynamic force on the wall gondola train from granular goods, the dynamic condition was established. Moreover, for three materials, sand, wheat and washed coal, their dynamic pressures on the wall of gondola train are analyzed. Also as for the three parameters,δ,φ,θ, their effects on the dynamic pressure on wall of gondola train have been studied. Then the granular flow method is used to verify the dynamic model. The granular flow method is used to obtain the dynamic pressure on the wall of gondola train, which carries different goods and runs at different speeds. The result is compared with that obtained by the Column Soil Pressure theory. It shows that there is a little difference. Contrast to the latter, the former shows the pressure distribution on walls nonlinear, which acts on the location different from 1/3 height; the pressure distribution and the act position are influenced by the train wall friction, the granular material, and the train operating parameter. The detailed are: as the friction of the granular goods rises, the static pressure become less, and the act height descend; the dynamic pressure rise, and the act position descends. As the friction angle rises between the train and the granular, the static pressure becomes small, and the act position moves up; the dynamic pressure rise and the act position become rise. As the impact speed rise, the dynamic pressure increase and its act position rise. Moreover, the time that the maximum force appears is related to the goods data and the operating parameters.It realized the numerical simulation of dynamic two-phase flow in tank train based on the Volume of Fluid method (VOF) model, and the method is directly put into use in the computation of the force of tank car from fluid flow. The result shows that: when the tank train brakes, the end wall in the moving direction will occurs larger force; the force quickly reaches the maximum value and then slosh to fade. The force value is closely related to the initial brake speed. The maximum force are linear to the initiate brake speed at some extend. The brake speed is small influence to the slosh wave amplitude. The time that peak value of force appears is effected by the impact speed, liquid material property, and the amount of liquid goods. The baffle in tank train is advantage to pull the fluid wave down, and the produced force is lower at the first stage of impact, which helps to improve the tank train operating safety.