Performance Analyses Of Emergency Working Condition Based On Airspring Burst Troubles Of High-speed Rolling Stocks

Compared with normal vehicles, after the air-spring bursts there are material difference between and the others. There are two basic contradictions throughout the application of the high-speed railway, such as:the sensitivity of the wheel-rail wear, and the problems of insufficient stability margin of bogie; the car-body yaw damping, and the problems of the Stability robustness of the high-speed railway. For the high-speed railway, it is unreasonable to treat the problem of air-spring burst with traditional view; otherwise, we have to take a risk with safety. As a result, air-spring burst has become one of the invalid working conditions. It is very important to carry out certain safety analysis and evaluation towards invalid working condition.After the air-spring bursts, the relationship between car-body and the interface of running gear has changed. There are two features:both friction plates creeping and stick-slip vibrating. So restraining the stick slip vibration is a suitable way to deal with the burst emergency. According to the features of interface, this article shows the modification of the corresponding bogie models. Through the mode analysis towards the whole train, the accuracy has been tested. According to the stability analysis of closed-loop system, analyzing the perturbed influence of the trailer stability behavior made by the air-spring burst, and also analyze the other relevant non-linear critical speed. The stability performance shows that lateral stiffness of air-spring is replaced by creep-slip caused by the contact between both friction plates, which will further increase the modal damping of car-body yaw even up to100%. The result of non-linear simulation analysis indicates that the friction plates will generate more obstruction whose sticky-slip vibration makes the relevant bogie lose its balance meanwhile makes the phenomenon of swing of locomotive much worse. At present regulation for the speed limits to160km/h, which is practicing in the accident of China high-speed railway air-spring burst, and will cause a significant security risk. As a result of a long anti-dragged braking time, there might be some uncertain safety risks. According to friction damping mechanism, in order to restrain the sticky-slip friction, applying antifriction materials can decrease the creeping-slip factor of the friction plates. The stability of the whole train analysis shows that the car-body yaw large damping is properly decreased thereby improving the stability of the whole train. The dynamic simulation analysis shows that track-shift lateral force, lateral acceleration of bogie frame and other running gear safety index are within safe levels, however, the lateral acceleration of the car-body is0.5m/s2 higher than the standard. Considering the contact of lateral bump-stop caused by curve deficient super-elevation and surplus super-elevation, it is constructive to run at a normal speed towards the next railway-station as soon as possible in order to get repaired when the airspring burst.In conclusion, the relationship between car-body and running gear has changed after the air-spring bursts that will make the basic two contradictions of the high-speed railway worse. Therefore, in order to guarantee the safe operation, it is possible to pay more attention to restraining the sticky-slip vibration of the friction plates, rather than limiting speed at160km/h. Spreading glycerol or molybdenum disulfide between both friction plates are ways of decreasing the creeping-slip factor, and finally to restrain the sticky-slip friction. Both the stability analysis and the dynamic simulation analysis show this technical measure can work effectively on restraining the sticky-slip friction. Consequently, for the high-speed railway, it is unreasonable to copy conventional vehicles’emergency technical measures on air-spring bursts. Being faced with new problems, some new solving measures should be put forward.The research projects from this paper have been supported by some projects as following:1. National sci-tech support plan:Common Foundation and System Integration Technique about Key Technology Research&Development of Equipment (2009B AG12A01) on China High-Speed Railway;2. The Project on Ministry of Railway Science and Technology R&D; The Regulated Research on Security and Stability Margin of High-speed bogie (2011J013-B);3. Southwest Jiaotong University Tractive Power Open Projects on State Key Laboratory:The Regulated Research on Security and Stability Margin of High-speed Railway (TPL1102).