Railway Wheel Profile Optimization Design Based on Nurbs Curve

Wheel and rail geometries, involving both cross sectional profiles and geometry along the moving direction with varying shapes due to wear, have a significant effect on vehicle dynamic performance and operating safety. A wheel profile optimal design method based on nurbs curve was present in this paper. The wheel profile is obtained for given rolling radii difference function ` ´ and rail profile. The optimality criteria formulated using the requirements to railway track and wheelset, are related to geometrical wheel/rail contact characteristics. During the optimization the shape of a wheel profile is varied in order to minimize the difference between the calculated and given rolling radii difference of a wheelset. The vehicle stability, wheel maintenance, passenger´s comfort and safety requirements to optimal wheel design have been taken into account during the optimization as well. These requirements have been considered as constraint functions, which mean that for an optimal wheel design the values of corresponding structural responses should not exceed certain prescribed values. The case of City Railway Vehicle wheel is considered. Finally dynamic simulations of vehicle with obtained wheel profile have been performed in ADAMS/Rail program package in order to test the wheel/rail wear and safety requirements.