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This paper describes new target interrogation and terminal ballistic loading and response models for partial impacts between tumbling long rod penetrators and spaced plate targets. The partial impact rod response algorithms differentiate full impacts from overlapping and overlaying partial impact geometries. For a partial impact, existing full impact penetration models are applied to just the portion of the rod that engages the plate to determine its immediate post-impact linear and angular momentum vectors and its integrity (shattered, shear fracture, bent, etc.). The unengaged portions of the rod are presumed to momentarily retain their pre-impact momentum vectors. The immediate post-impact velocity differentials between the engaged and unengaged portions of the rod are used to determine if the rod fractures or deforms. Momentum conservation routines are applied to determine the final post-impact linear and angular momentum vectors for the combined rod or fractured rod pieces. A plastic shear wave model is used to compute the associated rod deformation and shape change. Sample model predictions are compared with numerical simulation results to confirm the reasonableness of the model and its underlying assumptions. 2003 Elsevier Ltd. All rights reserved.

This paper describes experiments to record deformation profiles versus time in metallic rods subjected to transverse ballistic impacts. Rod materials included a tungsten alloy, four alloys of steel, titanium, and copper. The deformation profiles were analyzed to determine time resolved transverse plastic deformation wave speeds in all the rod materials and to estimate effective fracture shear strains in some of the materials. These material parameters are key elements in an analytical model to estimate deformations and failure in long rod penetrators subjected to transverse loads arising from non-ideal plate penetration geometries (yaw and obliquity). The rod materials were also subjected to tensile tests and Taylor anvil impact tests to measure static tensile and dynamic compressive strengths and longitudinal plastic wave speeds. The Taylor anvil and transverse rod impact tests together furnish the required dynamic material properties for comparing the penetration effectiveness of candidate rod materials and geometries.

Summary This paper describes the development of mechanically coupled engineering models to predict transverse loading and response of long rod penetrators associated with high velocity perforation of thin to moderately thick plates. Test results for L/D = 20 tungsten alloy rods are presented to illustrate the distinct effects of impact yaw and obliquity on terminal ballistic transverse loading and response of rod penetrators. The yaw effects loading model considers the plate cutting contact force that travels down the side of the rod when yaw is sufficient for contact with the edge of the breaching hole. The obliquity effects model addresses transverse loading due to asymmetric pressure relief as the rod approaches the rear surface and exits the plate. In both cases, the loading is presumed to be impulsive and three-dimensional vector relationships are used to account for the complex encounter geometries associated with arbitrary combinations of impact yaw and obliquity. The response model includes predictions of rod deformation and fracture and post-perforation linear and angular velocity vectors of the residual rod. Model predictions are compared with test results for titanium and tungsten alloy rods.

This paper describes experiments and the development of a model to predict damage to metallic plates impacted by high velocity, multi-particle debris clouds. The experiments involved single steel spheres fired at a steel shatter plate at speeds near 1.5 and 2.0 km/sec to generate the debris clouds. In each series of tests, the impact velocity was controlled, and a witness plate was placed at increasing distances behind the shatter plate to observe the effects of debris particle dispersion on plate damage. This paper focuses on the variations, with plate spacing, in the size of the central region removed from the witness plates. The central hole size model compares the post impact kinetic energy distribution in a witness plate impacted by a debris cloud to the free impact residual kinetic energy in an equivalent plate impacted by an L/D =1 steel cylinder, at the ballistic limit velocity. This approach permits extension of the model to other plate materials through utilization of existing ballistic limit velocity data.