Electromechanical performance of rails with different cross-section shapes in railgun

Railgun is one kind of the electromagnetic launchers that can accelerate masses in the range from milligrams to tens of kilograms to velocities in excess of several kilometers per second. Inertia moment is one of the most important mechanical properties of rails affects the critical velocity and launching performance, and the current distribution in railgun determines its efficiency and affects rail/armature sliding contact performance. Factors that affect the electromechanical performance of rails include geometry and material. In order to acquire increased electromechanical performance, two types of rails with convex and concave cross sections are designed by adding and removing arch form on the conventional rectangular rails, and the optimum solutions are solved under the given conditions of cross sectional area and rail width. Modified C-shaped armatures are constructed for each rail geometry. This paper presents mechanical performance results from structural analysis and current distribution results from coupled EM-structural simulations where velocity skin effect is considered. The results show that for the given cross sectional area and rail width, convex type rail has the biggest inertia moment and critical velocity among the three types, and the current distribution performance in railgun of the convex cross section rails are best, and the current density at rail/armature contact interface is most even.