Rail damage patterns and contact state evolution characteristics of electromagnetic launch

The rail damage characteristics are a crucial factor affecting the contact quality in electromagnetic launch, while the interface current and temperature are critical parameters determining the contact state. To improve launch quality and guide equipment design, this paper establishes an electromagnetic launch experimental and testing platform to analyze the rail surface damage patterns. Based on the experimental results, simulation models for different contact states are constructed, and the interface electrothermal characteristic distribution is calculated. The results indicate that mechanical friction occurs initially between the armature and rail, followed by the formation of a liquid metal film under the action of high-temperature, which not only reduces surface roughness but may also trigger gap discharge. Increased peak value of the pulse current and the number of launches exacerbate the damage. During the launch process, current density and high-temperature areas are primarily concentrated at the rear end of the armature-rail contact surface and in regions with high curvature, with abrupt changes observed at phase transition points. Finally, considering the variation of contact resistance, optimization proposals are presented for the front, middle, and rear segments of the rail.