Optimizing study on the concave arc surfaced C-shaped armature with medium and small caliber

Previous studies on solid armatures show that in a railgun system, concave arc surfaced C-shaped armature (ASCA) can improve the contact pressure and current distribution at the armature/rail (A/R) interface. However, concrete design or parameter study of the concave ASCA is rarely mentioned. In fact, besides the basic structural parameters for conventional C-shaped armatures, there are two more key structural parameters for concave ASCA, namely the radius (r) and the central angle (θ) of their surface arc. In this paper, three matching models of concave armature contacting with corresponding rail structure are discussed and compared, and consequently the best structure pattern of the contact is presented. Meanwhile, the radius and the central angle of the arc in the ASCA are proposed and analyzed. With a fixed railgun caliber and minimum thickness of armature trailing edge, the optimal θ and r are determined according to the current distribution obtained in simulation. The concave ASCAs for square-caliber railgun of 20 mm, 30 mm, 40 mm and 50mm calibers are discussed, and their optimal structural parameters are presented respectively.