Design of asymmetric grinding for curved rail based on multi-objective optimization strategy
Rail grinding of railway curves has always been a key focus of maintenance and repair work. While rail wear is inevitable,proper grinding profiles can effectively slow rail wear. To reduce the removal volume of grinding,improve the wheel-rail contact performance,and enhance the safety and economy of the railway system,a design method for curved rail grinding profile based on Multi-Objective Covariance Matrix Adaptation Evolution Strategy (MO-CMA-ES) was proposed. First,representative wear profiles were selected as the initial population using Principal Component Analysis (PCA) from rail wear profiles. Subsequently,a curve mathematical model was established by fitting these profiles using the NURBS curve fitting algorithm. Then,the MO-CMA-ES algorithm was used for multi-objective optimization,with the objective functions including reducing the removal volume of grinding,wheel weight reduction rate and axle transverse force. The population evolution was carried out with successive iterations based on the fitness values of each profile under different objective functions iteratively until the termination condition is satisfied,i.e.,the fitness function value no longer significantly changes. Finally,the offspring individuals with the smallest target fitness values were selected from the final population as the optimal solution. The optimized results show that the rail profile reduces the grinding removal by 45.3％,and the grinding reduction heights at the inner and outer rail tops are reduced by 0.84 mm and 0.23 mm,respectively. In terms of static wheel-rail contact,the optimized wheel-rail contact point distribution is more uniform,and the jumping phenomenon in the transition area of the gauge angle is improved. In terms of dynamic mechanical properties,the optimized rail profile reduces the lateral acceleration of the train body and the lateral force between the wheel and rail. Additionally,it effectively reduces the lateral displacement of the wheelset and slightly decreases the maximum contact stress between the wheel and rail. These findings provide an intelligent design method and reference for curve rail grinding.
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维普
