Analysis of Long Rods Impacting Ceramic Targets at High Velocity.
Final rept. Oct 95-Oct 96,
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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This paper presents an analysis of recently reported experimental data on penetration of semi-infinite ceramic and metal targets by long rods at relatively high velocity up to 4,500 ms. Data examined were for pure tungsten rods having length-to-diameter ratios of 15 and 20. The rods were impacted by confined aluminum nitride AlN, alumina Al2O3, and a metal target of aluminum in reverse ballistic tests. Penetration rates were reported to be essentially constant throughout the penetration process at all impact velocities considered. Further, depths of penetration characterized as primary penetration agreed with expected levels based on measured penetration rates and rod erosion rates. However, above an impact velocity of about 2,000 ms, considerably more penetration was observed in A1N and aluminum targets. In this effort, established techniques were used to treat penetration into semi-infinite ceramic, to include the high initial strength of the ceramic and its degradation, in time, through time-dependent damage mechanisms. The model results agreed with reported primary penetrations for A1N and aluminum targets. Further, additional secondary penetration by the rod erosion products at these high impact velocities was explored. This report includes detailed descriptions of the analysis and some physical interpretations for the observations. This research was based on U.S. Government-sponsored work and open literature sources.