Multiobjective Optimization of CRH3 EMU Wheel Profile

The wheel-rail wear problems inherent to railway operation have become increasingly prominent and serious, as they have been proven to be the main factors which affect safety, stability of electric multiple units (EMUs), and wheel-rail maintenance cost. The multiobjective optimization model of CN wheel profile proposed in this study was constructed in effort to reduce the wheel wear of CRH3. Reconstruction of the CN profile based on the nonuniform rational B spline (NURBS) curve theory was designed. Twenty vertical coordinates of the CN profile were selected as design variables, the first wheelset mean wear workand the wheel-rail lateral force were employed as the objective functions, and the wheel geometry, maximal contact pressure, and the derailment coefficient were chosen as the constraint conditions. Particle swarm optimization (PSO) was applied to complete the optimization model combined with the vehicle track coupling dynamics model. Analysis results indicated that the optimized CN-Opti profile possesses more favorable, comprehensive, dynamic, and effective characteristics than the traditional CN profile