Research On The Lateral Pressure Caused By The Coal Of The Hopper Car Body

Because the hopper car has some characteristics in faster moving vehicles, higher unloading-goods efficiency, it has been widely applied in the fixed loading and unloading areas such as power plants, mines, docks. However, with the development of railway vehicle towards high speed and heavy-duty, some problems of the hopper car-body turned out that side wall bulged and the supported roots of the end wall cracked, which posed a greater threat to safety of railway freightage. In the existing railway truck standard TB/T1335-1996 "the strength design and test appraisal regulations for railway cars", only the lateral pressure of the vertical wall can be calculated, but the solution method of the lateral pressure of the hopper car-body with circular plate structure is not perfect. Therefore, this paper researchs on a certain type coal hopper car with circular plate structure, research static and dynamic lateral pressure of the size and its distribution caused by granular coal on the hopper car body, in order to provide technical storage for the perfection of our country hopper car side pressure calculation standard and to provide guidance for the optimization design of the hopper car body structure. The main research content is as follows:(1) Using the method of level-layer analysis, this paper respectively sets up static lateral pressure mathematical model of sloped end wall and circular plate sidewall of the coal hopper car. Based on the established mathematical model of static lateral pressure, the static lateral pressure size of the side walls and end walls of the coal hopper car and its distribution has carried on the theoretical research. This article also researches the end wall angle, internal friction angle of granular coal, the friction angle changes of granular coal and hopper car on the influence of static lateral pressure distribution law.(2) Based on the discrete element method, the full vehicle discrete element model is established when coal hopper car is full load, in order to research the static lateral pressure of the end and side walls of the coal hopper car and their distribution. Based on the above discrete element model of coal hopper car, this article researches internal friction angle of granular coal, the friction angle changes of granular coal and hopper car on the influence of static lateral pressure distribution law. The results show that the static lateral pressure size and its distribution of the end and side wall which is got by means of the simulation is consistent with the result through the theory. The static lateral pressure of the end wall showed a trend of linear distribution, and the static lateral pressure distribution trend of lateral wall present nonlinear concave curve.(3) Research on the dynamic pressure of the hopper car body caused by granular coal in the process of discharging with low speed. Based on the discrete element method, this article sets up a simulation model of hopper car unloading test at a constant speed of 2 km/h, and compares discharging time of the simulation with the experimental discharging time, so as to validate the correctness of the accuracy of the simulation model of the hopper car unloading test. Based on the above simulation model of hopper car unloading tests, this article studies the lateral pressure and time of discharge of the hopper car body at discharging speed of 5 km/h.(4) Using the method of level-layer analysis, this paper established the dynamic lateral pressure mathematical model of coal hopper car end wall under the impact conditions. Based on the above model, the law of dynamic lateral pressure development on the end and side wall of the coal hopper is researched with the change of friction angle between the granular coal and the open wagon, internal friction angle of granular coal and the impact acceleration.