Influence of Magnitude of Armature Interference on Static Contact Resistance

This article establishes a simulation model and a measurement experimental platform for static armature-rail interface contact resistance. By comparing simulation and experimental measurement results of different magnitudes of interference, the applicability of the Cooper-Mikic-Yovanovich (CMY) contact resistance calculation method in the assembly phase of railguns is validated. Subsequently, the relationship between the magnitude of interference and contact resistance is investigated. The results suggest that a moderate increase in the magnitude of interference leads to a decrease in contact resistance and an increase in robustness to assembly variations. The analysis of the components of contact resistance is conducted, which reveals that contact spots and uneven contact pressures jointly contribute to the increase/decrease of contact resistance. The current concentrating at the edges of the spots at the microscopic level leads to contact resistance. Additionally, at the macroscopic level, the current concentrating in regions with higher contact pressure results in contact resistance. According to the research, the increase in magnitude of interference can reduce the amount of both sources of contact resistance.