Research on the Mathematical Model for Wheel Profile Optimization with Arc Parameters as Design Variables

On the basis of analyzing the geometrical characteristics of arc wheel profile,four segments of arc were chosen to describe the contact part between wheel profile and rail.The radius of two end arcs and the center coordinate of two arcs in the middle of four segments were chosen as the design variables.The wheel/rail wear,critical velocity,and wheel rail lateral force were chosen as the objective functions.With satisfying the requirements for the maximum wheel rail contact stress,derailment coefficient,rolling contact fatigue factor,critical velocity and wheel rail lateral force as constraints,the arc wheel profile multiobjective optimization model was constructed.Taking ERRI 200 km·h-1 standard railway passenger vehicle for example,the proposed wheel profile multiobjective optimization model was adopted to optimize its wheel profile.The result shows that after optimization once,the sum wear index of the first wheelset of ERRI vehicle is reduced about 15% running on the curve track of 3 000 m radius,but the critical velocity is only 75 m·s-1.By adjusting the value range of the design variables,the optimal wheel profile Wheel_Opt was obtained after implementing wheel profile optimization.After adopting the optimal wheel profile,the sum wear index of the first wheelset of ERRI vehicle is reduced about 12% running on the same track and the critical velocity is increased to 105.9 m·s-1.