Computational design of hypervelocity launchers

The andia ypervelocity auncher (HVL) uses two-stage light-gas gun impact techniques to launch flier plates to velocities in excess of 10 km/s. An important requirement in designing successful third stage techniques for impact launching fliers to such velocities is detailed understanding of the interior ballistic performance of the third stage. This is crucial for preventing melt and fracture of the flier plates during the extraordinary accelerations that they undergo (10⁹ g). We seek to optimize HVL launch conditions in order to achieve two major goals: first, to maximize the potential launch velocity for a given flier, and second, to allow different flier configurations. One tool that we have applied in studying HVL performance are multi-dimensional wave propagation codes, particularly the Sandia Eulerian code CTH. Recently this work has culminated in a major contribution to HVL design, namely the capability to launch “chunk” fliers. The initial phases of design development were solely devoted to CTH computations that studied potential designs, identified problems, and posed possible solutions for launching chunk fliers on the HVL. Our computations sufficiently narrowed the design space to the point that systematic experimental progress was possible. Our first experiment resulted in the successful launch of an intact 0.33 gram titanium alloy chunk flier to a velocity of 10.2 km/s. The thickness to diameter ratio of this flier was approximately 0.5.