Optimal Design Of Rail Profile For The Curve Segment Of Heavy Haul Railway

With the development of Chinese railway construction, the increasing axle load is the trends. The increased heavy axle load results in the increase of rail-wheel force. When the wagons pass through the curve, wheels make great damage to the rail profile affected by the centrifugal force and additive drag. Side wear of outer rail on the curve is particularly heavy. Reasonable rail profile has important operation significance to the repair and maintenance work of heavy load railway, which will improve the characteristics of wheel/rail contact and dynamics performance, and reduce wear rate. Based on wheel/rail rolling contact theory, vehicle-track dynamic theory and nonlinear programming theory, the optimization design of sharp-radius curve rail profile is researched as below.(1)Based on wheel/rail contact geometry relationship, the contact theory, and coulomb law, Kalker rolling contact theory and Archard abrasion calculation theory are applied as the theoretical foundation of the optimization design of rail profile.(2)Based on the vehicle-track dynamic theory, 30 t axle load railway wagon and 600 m radius curve rail model is built for the dynamics analysis of railway. Dynamic safety performance evaluation parameters and 11 kings of simulation conditions are determined according to the curvature speed.(3)The abrasion process of 75kg/m rail and a design rail profile is analyzed by the simulation. It is found that the contact properties of each stage are different with the happening of rail wear. The minimum of mean value on wagon of wear loss and grinding amount in the rail design cycle is put forward to be the optimization goal.(4)The area between railhead center and gauge measurement point is determined to be optimized, according to the actual measurement of wear distribution of heavy-haul railway. Ten non-equidistant discrete points are determined to be the design points, the vertical coordinates of which is design variables. D-optimal design is used for the experiment design, 71 kinds of profiles are designed. Profile update strategy is based on the maximum of the wear depth, dynamic simulation is made to obtain the evolution process and dynamic response of experiment profiles in the 11 kinds of simulation conditions. The whole design space is made up of the 71 experiment profiles and their dynamic response. Gaussian radial basis function is used to build the approximate function of object variable and design variable as objective function, and the approximate function of dynamic safety performance evaluation parameters and design variable as constraint condition. Optimization model is built depend on the approximation model.(5)Genetic algorithm is used for the solution of the rail profile optimization model, an optimal solution set of optimized profiles is obtained, all of which have less wear loss and grinding amount per wagon in the rail design cycle and satisfy the dynamic safety performance evaluation parameters requirement. The passing gross load of profile CSY-1 reaches 150.74 Mt, which is an increase of 139.73% from the 75 kg/m rail profile.The rail profile optimization method based on radial basis function is proved to be effective to reduce heavy load railway diseases.