Association Analysis In Loading Reinforcement Safety Of Railway General Freight And Speed

With the rapid development of national economy and railway construction, high speed and heavy haul transportation is an important direction of Chinese railway freight. The freight loading reinforcement is the key to the running safety of freight car and security of freight. It is necessary to study the factors that affect the loading reinforcement safety, especially related to speed. The effects on the loading reinforcement safety caused by random excitation, curves lines, crosswind pressure, height or lateral offset of gravity center of loaded wagon and so on are increased as the speed increases, which makes it worse when several factors impact together. Based on the basic principle of loading reinforcement and vehicle system dynamics theory, this paper studies the relationship between vehicle speed and the loading reinforcement safety of railway general freight by dynamics numeric simulation which contains both dynamic characteristic of the freight car and random factors of the track. The specific contents of the study are as follows.(1) The domestic and foreign researches of loading reinforcement safety are summarized. Then, the loading reinforcement safety is divided into two aspects:loading safety and reinforcement safety. Meanwhile, the factors which affect loading reinforcement safety is analyzed, and the key factors that significantly related to velocity are confirmed. Index for loading safety and reinforcement safety evaluation are selected.(2) A complete dynamic model of freight loading is established by analyzing the topology of the most common bogies and general flat cars. Mechanical models of various types reinforcing devices are established. Take transport of a certain common goods as research object, a complete vehicle-freight reinforcement three-dimensional dynamic model is built.(3) The relationship between vehicle speed and loading safety is studied by numeric simulation. Loading safety with the changing of speed is investigated when freight cars running in tangent track, passing the curve and running under the crosswind with different height or lateral offset of gravity center of the loaded wagon. Then, the relationship between loading safety and speed is established which contains random excitation, curves lines, crosswind velocity, height or lateral offset of gravity center of the loaded wagon by analyzing the simulation results.(4) The effect of longitudinal impact on reinforcement safety is researched by numeric simulation. The impact loading between the freight cars is derived. The impact dynamic under different relative velocity is simulated. We get the dynamic response of the vehicle-freight reinforcement system in the whole impact process. The reinforcement safety is evaluated by longitudinal stability coefficient of freight, acceleration of freight and the force of the reinforcement device. Finally, the relationship between the reinforcement safety and impact relative velocity is obtained.Compared to the traditional empirical formula method, this paper uses the dynamic method to evaluate the loading reinforcement safety. Based on a complete and detailed dynamic model, more extensive and essential information is obtained, which is significant to the depth study in loading reinforcement safety and is proved to be an effective method. The results obtained in this paper could be a guidance in loading reinforcement evaluation and project design.