The Novel “Fracture” Gun at the DEVCOM Army Research Laboratory for Precise, Highly Instrumented Impact Experiments

Author(s):

Christopher S Meredith

Abstract:

This report describes the novel “fracture” gun recently built at the US Army Combat Capabilities Development Command Army Research Laboratory to study dynamic deformation and fracture mechanisms under impact loading using high-speed cameras with digital image correlation. This gun combines the precise projectile/target alignment capabilities typical of a plate-impact experiment with the ability to observe phenomena over a wide spatial and temporal scale. The velocity capabilities and the target tank are outlined. The target tank is small with large windows so that cameras can be placed very close to the impact location, which allows for small fields of view not typically achievable in these experiments. Velocity measurement, triggering, and lighting solutions are presented. There are very few experimental methods to probe fundamental deformation and fracture mechanisms within the ballistic regime, but this gun and the associated instrumentation are a big step toward better understanding these mechanisms.