Influence of Armature Movement Velocity on the Magnetic Field Distribution and Current Density Distribution in Railgun

In a railgun, the velocity of the armature has an important effect on the magnetic field distribution and current density distribution of the launch system. However, the calculation models established by scholars were mostly models under static conditions. They could not effectively reflect the velocity skin effect (VSE). This article uses the finite-element softwares COMSOL and LS-DYNA to establish a calculation model that considers the influence of the armature movement velocity on the magnetic field distribution and current density distribution. The calculation results show that when considering the armature movement, the magnetic field distribution of the rail side is very different from the static calculation result. Under the influence of the VSE, the current of the armature/rail (A/R) interface is mainly concentrated on the end of the armature's tail. When considering the armature movement, the values of maximum current density of the rail side doubled. Also, as the armature velocity increases, its range of influence also increases. However, it tends to saturate after reaching a certain velocity. Considering the influence of the armature velocity on the magnetic field distribution and current density distribution can make our results closer to the actual launch situation.