Study On Permitted Height Of Gravity Center Of Railway Loaded General Wagon

Permitted height of gravity center of loaded wagon is one of basic railway technical standards. The height of gravity center of loaded wagon can not over 2000mm in current Regulations on Loading and Securing of Railway Goods, else the wagon must be running by speed limit, so the permitted height of gravity center of loaded wagon is 2000mm in China. This standard originated from Manchuria railway for several decades, but it seems conservative as enhancement of the railway technology and improvement of the wagon performance, so it is an urgent problem to do research on the permitted height of gravity center of railway loaded wagon. The method of orthogonal experiment design is used to find out the most dangerous running condition, and the reasonable permitted height of gravity center of railway loaded general wagon is analyzed based on simulation experiment.The main research contents are as follows:(1) The method of orthogonal experiment design is used to arrange height of gravity center of loaded wagon experiment schemes, the number of the experiment schemes is decreased efficiently. The orthogonal experiment factors are confirmed as vehicle, railway line and velocity, goods loading. Levels of the factors are analyzed and experiment schemes are designed.(2) By using D’Alembert law, the carbody random vibration models which include the location of the gravity center of goods are derived. The sideframe random vibration models of the lower cross-braced bogie and swing motion bogie are derived as different wagons in the experiment.(3) Wagon models are built in SIMPACK simulation platform. By comprehensive analysis, the AAR5 and AAR3 track spectrum models are chose as track irregularity of Chinese I and III grade railway line, and they are transformed to time-domain to fit for the simulation platform.(4) The reasonable sampling frequency is confirmed as 100Hz by spectrum analysis of the high sampling frequency data. It can not only insure the precision of the result, but also can enhance the calculation efficiency. The simulation experiment result and the round testing railway line experiment result are contrasted, it shows that the simulation models are reliable.(5) The height of gravity center of loaded wagon experiment schemes are simulated, and then the most dangerous conditions are obtained by objective analysis and variance analysis. The relationship between uncertain factors and wagon running safety are comprehensive analyzed based on the simulation result. The safety of different height of gravity center of loaded wagon is analyzed under the most dangerous conditions. The permitted height of gravity center of railway loaded general wagon is analyzed based on simulation experiment.