Investigation of Damage to Solid-Armature Railguns at Startup

This paper describes work investigating a rail damage mechanism observed in solid-armature railguns at the Institute for Advanced Technology, The University of Texas at Austin. The damage occurs in the starting section of rails and is not associated with high-speed phenomena such as hypervelocity gouging or transition to arcing contact. The damage, which we call grooving, is localized to the region of the rails adjacent to the insulators. In this paper, we describe grooving damage observed in multiple tests using copper rails. In one series, in which we tested up to 20 shots on one pair of copper rails, we obtained grooves on the order of a millimeter deep and several millimeters wide. We present evidence that grooving is caused by liquid erosion and is not a result of plasma heating or mechanical deformation