Dynamics of Armature-Rail Electrical Contact Under Multi-Physics Field Coupling

The electromagnetic rail launcher works under the extremely harsh impact conditions involving the coupling of multiple physical fields such as extremely strong electromagnetic fields, extremely high thermal fields, and extremely high force fields. The touch state between aluminum alloy armature and steel guide rail is related to the output performance, response stability, operating efficiency, work reliability, and high energy consumption of the entire system, and the pulse current and the interface roughness have a significant effect on the contact state. An experimental platform for electromagnetic rail launching is built, and the rifling voltage, rail current and contact resistance are measured experimentally. A multi-physical field coupled armature-rail electric contact model is constructed, and the distribution laws of current density, temperature and magnetic flux density of the armature and guideway are analysed. Furthermore, the effects of current amplitude and friction factor on its dynamic characteristics and temperature and magnetic flux density are investigated. The results indicate that there is an initial peak in both the pulse current and the bore voltage, which decays after the armature exits the bore. The high-temperature and strong magnetic region of the system is located at the metal contact interface. The speed and force vary significantly with the amplitude and roughness of the current.