Joint U.S./ROK Research and Development Program for New Underground AmmunitionStorage Technologies. Dynamics and Kinematics of Oblique Impacts of Steel Fragments on Rock Surfaces

摘要

A series of 23 experiments were conducted to evaluate the dynamic and kinematicchanges induced by the impact of steel cubes against rock surface. The cubes were intended to simulate metal fragments from accidental munition explosions in underground magazines. Test parameters included rock type (limestone and granite), impact velocity (nominally 4,000 and 6,000 ft/sec), fragment weight (250, 500, and 700 grains), and angle of obliquity (30, 45, and 60 degrees). The data analyses indicate that 90 percent of the incident kinetic energy is lost as a result of fragment impact on a smooth rock surface. The steel cubes fractured upon impact, resulting in an average weight of the recovered largest fragment that was 56 and 86 percent of the pre-impact weight for granite and limestone, respectively. These limited test results indicate that munition fragments impacting rock surfaces at obliquities up to 60 degrees (impact angles of 30 degrees or more) will lose enough kinetic energy to greatly reduce the likelihood of secondary detonations initiated by their subsequent impact against other munitions.