Optimization of 60 kg/m Rail Profile Based on Improving Wheel-Rail Conformal Degree

Under the operation conditions of mixed passenger and freight railways as well as heavy haul railways, wheel/rail wear problem is particularly prominent. In order to slow down the growth of wheel/rail wear, the 60 kg/m rail profile is optimized. The objective function and constraint conditions are determined with the principle of optimizing the conformal degree of wheel-rail profiles under different contact conditions. Then, a nonlinear optimization model of the rail profile is established. The sequential quadratic programming method is adopted to solve this optimization model, and an optimization scheme of 60 kg/m rail profile is proposed. The effect of the optimized profile is compared and analyzed from the perspective of wheel-rail contact geometry, vehicle-track system dynamic interaction, and wear. The results show that: 1) the proposed optimized profile of 60 kg/m rail reduces the objective function value by 50%, compared with the original profile, and has higher conformal level with the LM wheel profile. 2) The distribution of wheel-rail contact points is more uniformly distributed on the optimized profile. The rolling radius difference is smaller when there is a small wheelset lateral displacement, and larger when there is a large wheelset lateral displacement. 3) The optimized profile has no significant influence on vehicle safety and comfort, and can effectively increase the wheel-rail contact area by 11.24%, reduce the contact stress by 20.42%, and slow down the occurrence and growth rate of wheel-rail wear. © 2022 Science Press. All rights reserved.