Simulations on Current Distribution in Railgun Under Imperfect Contact Conditions

In the process of electromagnetic launch, the initial contact pressure distribution of armature/rail (A/R) contacts interface is uneven, and the actual contact area is obviously different from the perfect contact. The uneven contact pressure leads to uneven contact resistance distribution, affecting the magnetic diffusion process and changing the A/R interface current distribution. Therefore, it is necessary to consider the influence of contact pressure on the current distribution. In the past, the simulation studies usually considered the contact between rails and armature as the perfect contact, and the result obtained may be different from the actual situation. This paper uses the finite element software COMSOL to perform coupling simulation analysis on the electromagnetic module and solid mechanics module in the initial stage of electromagnetic launch. At the initial stage of electromagnetic launch, the contact pressure is mainly provided by the prepressure generated by the interference fit. In this paper, the influence of contact pressure on current distribution and the influence of magnitude of interference on contact position, contact pressure, and current distribution are analyzed.