Research On Wheel Tread Optimization For Heavy Haul Wagon

The development of heavy-haul freight transportation and the increase of train weight, which are effective to enlarge railway transport capacity and improve transport efficiency, have become the developing direction of the railway transport and inevitable outcome of national route situation. However, due to causes such as the increase of train weight, more and more compositions, enlarged axle-load, the raised of the force of traction and brake, all these have led to railcars and facilities'damage, railways'deformation, severer workload of maintenance and the intensification of the wear of wheels and rails while becoming the crucial problem in the heavy haulage.Wheel-rail wear is inevitable while wheels run on the track. Meanwhile, because of more and more volumes of goods, the wear would be intensified. Thus, to optimize the profile of wheel tread and improve the wheel-rail contact conditions and the contact force between wheel and rail are necessary. On the one hand, it would make vehicles run on the track steadily and safely. On the other hand, it is propitious to ease wheel-rail wear and extend the service life of wheels, regarding of obtaining the best economic benefit. In this thesis, vehicle and wheel/rail system structure have been preset, we've chosen the best parameters for the wheel/rail geometry type surface match, the one can optimize a kind of wheel tread adapting to the75kg/m rail on the base of LM abrasion type tread.In this thesis, by analyzing the status for wheel-rail wear and models for predicting the wear throughout domestic and abroad, we have summarized that the wear models that could be used for wheels wear of heavy haul wagon, such as wear work wear model and Archard wear model. Firstly, software of calculation and multi-body system dynamics, SIMPACK, was used to model the heavy haul wagon of32.5t axle load. Then, it analyzed wheel-rail contact geometric relations of LM abrasion type tread respectively matching with the60kg/m rail and75kg/m rail. The wheel wear was also evaluated by using the two wear models by means of parameters such as wear index, angle of attack, the vehicle wear power, wheel-rail contact stress, the abrasion of depth for a single wheel-rail contact spot, vertical and horizontal creep force. The results indicated that, no matter whether in the straight line or curve, when LM abrasion type tread matched with the75kg/m rail, the volumes of the wheel wear were more serious, especially that of the wheel wear on the wheel tread rather than matching with the60kg/m rail.The optimization of wheel tread shape matching with75kg/m rail has a substantial significance for heavy-load transportation. That is reducing wheel-rail wear and prolonging the service life of wheel-rail. According to wear difference between wheel tread and flange contact position, this paper focuses on the optimization of tread position neared the nominal rolling circle of wheel tread, namely ranged from-2.5mm to7.5mm of rolling circle. On this basis, this paper presents four kinds of tread optimization schemes, all of them matching operated with the75kg/m rail, and then the wheel abrasion loss was analyzed. The optimization research showed that when the optimized tread was running matched with75kg/m rail the wheel wear was significantly improved and other dynamics performance were good.