Experimental and Simulation Study of Deposition Layer on Rails in the Startup Stage of Armatures

The startup of the armature has a significant influence on the whole launching process. During the launching, the rail-armature interface suffers high current density, high temperature, high contact pressure and high velocity. The condition of the rail-armature interface increases the complexity of the launching and enable the appearance of the deposition layer. The sliding electrical contact on the rail-armature interface is affected by the deposition layer. The deposition layer also changes the characteristics of contact interface, such as roughness, hardness, and thickness. In this paper, the deposition layer on rails after three launching experiments was investigated. The thickness of the deposition layer was measured by three-dimensional (3D) laser profilometer. The mass of rail blocks of the armature startup stage was measured. Moreover, the dynamic multi-physics field simulation model of startup stage was established. The temperature and current density in startup stage of the interface between the armature and rails were calculated. Three conclusions are obtained. 1) In three experiments, the deposition layer of cross section of rail blocks occurs peaks and fluctuations. The peak value of anode is larger than that of cathode, and the fluctuation of anode is more than that of cathode. 2) The mass of rail blocks increases with the number of experiments. The mass difference of the anode rail block is smaller than that of cathode. 3) The current density and temperature are concentrated at the edge and the rear of the armature.