Studies on Interference Fit Between Armature and Rails in Railguns

There is an interference fit between the trailing arms of the monolithic C-shaped armature and the rails to provide good solid-on-solid contact during the early portion of a railgun launch. In this paper, the contact interference between the rail and armature in a railgun is calculated using a finite-element structural analysis code. The contact properties, including the contact pressure and contact area, are analyzed. It is found that a contact separation caused by the interference is inevitable in armatures with line-shaped contact interference. The reduction of the contact interference in an armature design cannot eliminate this kind of contact separation. A proper design of the armature structure can decrease the length of the separation effectively. A new design of the contact interference is proposed. Both the experiments and calculations show that the new design of the contact interference can effectively improve the performance of the armature.