Armature Technologies and Launching Capability of Electromagnetic Railgun Launcher with Monolithic U-shaped Aluminum Armature

The progress and limitation of launching capability for an electromagnetic railgun launcher were analyzed referring to the armature technologies. The monolithic U-shaped aluminum armature could be used to launch efficiently a projectile to 2.5-km/s hypervelocity owing to such nine aspects of characteristics as low density, high conductivity, low specific heat, suitable melting point, low melting heat, high mechanical strength, U shape to undertake the interference fit between rail/armature sliding interfaces, U shape to conduct longitudinal current, U shape to distribute current to try to avoid local gathering. The reliable sliding electric contact between rail/armature was well controlled to depress friction, abrasion, transition to discharge erosion, gouging, and grooving. However, such four aspects of characteristics as the heavy pulse current of MA magnitude, the current gathering on the concave surface of U-shaped armature, the local Ohmic heat to melting, and the magnetic saw effect did limit the launching capabilities of an electromagnetic railgun launcher with a monolithic U-shaped aluminum armature. The simulation results showed that the muzzle momentum had a limited value of about 15 kg × 2.5 km/s for a railgun launcher. The results reached were: the monolithic U-shaped aluminum armature could successfully launch a 15-kg projectile to 2.5 km/s; The evaluation index of the launching capabilities for an electromagnetic railgun launcher was the muzzle momentum, not the muzzle velocity or the muzzle kinetic energy, owing to magnetic saw to break the armature; a kind of double-layered U-shaped aluminum armature might help to launch a 60-kg projectile to 2.5-km/s velocity.