Effect of Structural Parameters on the Startup Contact States in Revolving Armature

Abstract

The revolving armature can effectively improve the firing accuracy of the railgun, which rotates at high speed under the action of electromagnetic force during the movement in the bore. However, the research on the influence of the armature structural parameters on the startup contact state between the armature and the rail is rarely involved. In this article, for a 15-mm caliber railgun, the finite-element calculation model of the revolving armature assembly process of interference is established, and the interference fit of the traditional revolving armature with different structural parameters such as crack length C_L and width C_w, interference amount $d_{1}$ , tail thickness $t$ , and length $L_{1}$ is calculated, and the influence law of the structural parameters of the rotating armature on the initial contact states–contact area, contact force, maximum equivalent stress, and plastic volume is obtained. Second, on the basis of the traditional revolving armature, an armature structure with interference at both ends leading edge and trailing edge is proposed, and the influence law of interference at the leading edge and the middle turning position on the contact ratio at both ends of the new armature is obtained. Finally, the startup contact states of the new armature, the traditional long-arm armature (tail length 18 mm), and the short-arm armature (tail length 14 mm) are compared. The results show that the new armature can significantly reduce the equivalent stress and plastic volume of the armature.