Research On Safe Running Velocities Of Railway General Wagon With Different Combined Gravity Center Heights Of Loaded Car

The combined gravity center height of loaded car is one of basic railway technical standard.In current Regulations on Loading and Securing of Railway Goods,both combined gravity center height limitation with nonnal speed and speed limit beyond permitted combined gravity center height,are conservative.To a certain extent,the rule has hindered the improvement of railway freight transport efficiency,and has restricted the development of railway freight transport.Therefore,it is urgent to do research on the safe running velocities of railway general wagon with different combined gravity center heights of loaded car.Through the research in this paper,the permitted combined gravity center height with normal speed and speed limit beyond permitted height will be raised reasonably on the promise of ensuring transportation safety.It will effectively improve the capacity of railway transportation and promote the development of railway freight transportation in China.In this paper,the method of uniform test design is adopted to arrange the test schemes,and the reasonable safe running velocities of railway general wagon with different combined gravity center heights of loaded car is analyzed based on simulation test.The main research contents include the following aspects:(1)According to the analysis on the adaptability of the derailment criterion in China,this paper proposes to introduce the actual effective friction coefficient "μe"instead of Coulomb friction coefficient "μ" to the classical Nadal derailment formula,and deduces a dynamic derailment criterion for evaluation of vehicle operational safety.(2)The factors affecting the operational safety of vehicle,such as vehicle type,line condition,cargo weight,transverse deviation of cargo gravity center,longitudinal deviation of cargo gravity center,running speed and wind force,are analyzed.Using these factors,the experiment schemes of this paper are arranged by using the method of uniform test design.(3)Based on the theory of multi-body system dynamics,the freight-vehicle-rail/turnout system dynamic models are established.(4)According to the freight-vehicle-rail/turnout system dynamic models,the dynamic simulation models of freight-vehicle-rail/turnout system are built in SIMPACK simulation platform.Then the simulation models are testified to be reasonable by comparing the test results of simulation model with the test data in the railway operation line test and the test data of previous literatures.(5)Based on the dynamic simulation models,the experiment schemes designed in this paper are simulated.Then the simulation results are analyzed based on the dynamic derailment criterion.Finally,a new reasonable safe running velocities standard of railway general wagon with different combined gravity center heights of loaded car is put forward.