Rails for electromagnetic hypervelocity launcher

摘要

An electromagnetic launcher is provided for accelerating a projectile from a breech end to a muzzle end. The launcher includes a container, a rail contained therein and a support. The container includes an inner surface along an axial direction. The rail is contained within the inner surface and includes a load surface to support the projectile and an interface surface. The support is disposed between the interface surface and the inner surface. The rail and the support provide a value to an expression for critical velocity; $$ V_{\mathrm{cr}}=\sqrt{\frac{2\sqrt{\mathrm{EIk}}}{\rho A}},$$where E is Young's modulus for the rail, I is moment of inertia for the rail, k is foundation modulus for the support, ρ is density for the rail and A is the cross-sectional area of the rail. The launcher is configured such that the critical velocity increases along the axial direction towards the muzzle. In particular, a material term √E/ρ of the rail increases along the axial direction, such for the rail being made from a first material being proximate to the breech and a second material being proximate to the muzzle, such that the material term √E/ρ of the second material being greater than that of the first material. Alternatively, the rail is made into a first shape being proximate to the breech and a second shape being proximate to the muzzle, such that a shape term √I/A of the second shape is greater than that of the first shape.