| Rail is the most important component of track structure. It directly contacts with the wheels of rolling stock, and has to bear the wheel-rail load. In addition, rail is also subject to temperature load, etc., and the actual force bearing status is very complicated. Under the long-term load, rail will suffer from various injuries. With the increase of China’s rail mileage, the maintenance work of rail is required to be more effective. Reasonable grinding for rail can not only renovate its profile, but also improve the dynamic performance of the vehicle.In this paper, the author conducted on-site tests on the rail profile before and after grinding in a railway line of Shenyang Metro. By referencing to the regulations on rail profile after grinding in the national performance standard for grinding vehicles, a contrastive analysis was made on the rail profiles, before and after grinding, during different stages of grinding operation, and after grinding with two schemes. The results show that the match of the grinded rail with the standard vehicle wheel made the light strip for wheel-rail contact become more uniform and increased the contact area larger, thereby reducing the contact stress between the wheel and rail.Using the multi-body dynamics software SIMPACK and basing on the profile data of rail before and after grinding as well as the requirements for rail profile in the national standard for grinding operation, we established the dynamic vehicle/rail models before and after grinding, then respectively calculated and analyzed the derailment coefficients, stability indicators and lateral force indicators between wheel and rail, for vehicles on the straight and curve rail, before and after grinding. The results showed that rail grinding could reduce derailment coefficients and lateral force indicators of vehicles and improve vehicle stability, but had little effect on the dynamic performance of the vehicle.By calculating the frictional power of wheels under different schemes before and after grinding, contrastive analysis was made based on the results. The results showed that, the maximum frictional power appeared in the situation where a 60kg/m rail was matched with a standard LM profile, and the minimal frictional power occurred in the rail that was not grinded after abrasion. After grinding under two schemes, the maximum vehicle frictional powers were between the frictional power upon the match of standard wheel with rail, and that upon the match of wheel and rail after worn. It can be proved that, by means of rail grinding, the wear between wheel and rail can be reduced, stress conditions between wheel and rail can be improved, the contact fatigue between wheel and rail can be controlled, thus extending the service life of the wheel-rail.Through the calculations on the traverse quantity of wheel set of standard wheel-rail, rail after worn and wheel-rail after grinding in two different schemes. According to the comprehensive analysis of the changing curve of the rolling radius difference to the transverse quantity for the wheel set, it can be seen that when the rail ensured reasonable range for the transverse quantity of the wheel set after worn, it could not provide a reasonable rolling radius difference for the wheel set. The transverse quantity of the wheel set slightly increased after grinding, but the wheel set could get the rolling radius difference similar with that of standard wheel-rail, thus reducing the violent abrasion between wheel and rail due to the sudden increase of the rail rolling radius difference caused by abrasion. |
PDF Full Text Request