Experimental Study On The Influence Of Strip Vibration On Friction And Wear Of A High-Speed Pantagragh And Cantanary System With Electric Current

Our country is vast in territory. Therefore, it is very suitable to develop the high-speed railway transportation. Up to now, the total traffic mileage of the high-speed railway lines has arrived at more than 10,000 kilometers. The wheel-rail relation, pantograph-catenary relation and air-carbody action relation are three most important interactions in the high-speed railway technology, which have very key influence on the safe operation of high-speed trains and the decrease in maintenamce costs. The operation experience of China’s high-speed trains shows that a failure in the pantograph-catenary system very easily results in a breakdown of the whole high-speed train. Under the high-speed running, the work condition of a pantograph contact strip rubbing against a catenary contact wire becomes very worse. The material losses of the contact strip and contact wire are very severe. To obtain the solution to severe losses of the contact strip and contact wire, the author carries out a series of experimental tests on a contact strip rubbing against a contact wire with electric current at high speeds on a high-speed test machine. The main research work and conclusions are introduced as follows.1. The author carries out a series of experimental tests on a pantograph contact strip rubbing against a catenary contact wire at high speeds. The research work is focused on arc discharge occurring during the friciton process. Based on the test results, the arc discharge is divided into three categories. The arc discharge in the different category leads to a different damage on the worn surface of the contact strip. The test results also show the normal load can reduce arc discharge. The wear rate and the surface temperature of the contact strip both present approximately linear relations with the arc discharge energy.2. The author investgates into the mechanism for arc discharge in a contact strip rubbing against a contact wire with electric current at high pseeds. Numerous tests are carried out. The results show that the wear mechanism of the contact strip obviously changes with the increase of test time. The results also show that the vibration of the contact strip and the arc discharge energy aggravate gradually with the increase of test time. The correlation between the arc discharge energy and vibration of the contact strip is analyzed. It is found that the arc discharge energy is highly correlated with the vibration of the contact strip.3. The author conducts a large number of experimental tests using two kinds of contact strips to study the effect of contact strip vibration on arc discharge and the wear behaviour of the contact strip with electric current. During testing, the vibration of contact strip is measured. The results show that the vibration aggravates the intensity of arc discharge. In the sliding process, the friction coefficient of two kinds of contact pairs (pure carbon/copper contact wire, metal-impregnated carbon/copper contact wire) decrease with the increase of the vibration acceleration, and the value of the friction coefficient maintains between 0.2 and 0.35. Under the same test conditions, the friction coefficient of pure carbon strip is always bigger than that of the metal impregnated carbon Meanwhile, the wear rates of two contact strips increase with the increase of the vibration acceleration. The vibration of the contact strip speeds up wear of the contact strip. The wear resistance of the metal-impregnated carbon strip is better than that of the pure carbon strip. The effect of the vibration on the wear mechanisms of the contact strip is obvious. When the Vibration is smaller, the main wear mechanisms of the two contact strips are abrasive wear and adhesive wear. However, when vibration is larger, the main wear mechanisms of the pure carbon strip is arc erosion such as erosion pits and thermal stress crack, and arc erosion and flake-like delamination is the main wear mechanism of the metal-impregnated carbon. In addition, the non-conductive area increases with increasing vibration of the contact strip. The conductivity of the pure carbon strip is better than that of the metal-impregnated carbon under the same test conditions.4. The author carries out a large number of experimental tests on a contact strip rubbing against a contact wire with electric current at speeds of 200-350km/h. The test results indicate that under the conditions without electric current, the vibration of the contact strip, contact surface temperature rise and the wear rate of strips are approximately kept constant. However, the test speed has a great influence on the vibration of the contact strip, the friction and wear properties such as contact surface temperature rise, the wear rate and the topograph of worn surfaces.