A Bond Graph Model of an Electromagnetic Launcher—Part 2: Simulation Results

An electromagnetic launcher (EML) or railgun is a complex dynamically coupled system, with interacting electric, magnetic, mechanical, and thermal subsystems. Part 1 of this paper formulated a bond graph model of an EML system, including power supply, dynamics of power cables, electric dynamics of armature and rails, magnetic containment of flux, electric contact resistance between sliding armature and rails, generation of forward longitudinal motion, transverse contact mechanics of armature sliding on rails, thermal analysis of armature heating, and model of armature melt wear and plasma erosion. Using state equations extracted from the Part 1 paper, numerical simulation results of the Institute of Advanced Technology's MCL EML are presented. Simulated are rail current, armature forward motions, armature-rail contact normal approach, armature and interface temperatures, and material loss. Results are compared to MCL shot 185. The results suggest interface temperatures of thousands of kelvins, which can exceed 15 000 K under certain conditions, and an armature-rail sliding contact separation due to accumulated melt erosion, consistent with transition.