FINITE ELEMENT SIMULATION OF OBLIQUE IMPACT LOADING ON METALLIC PLATES

Abstract

Impact is defined as the collision of two bodies. The field of impact dynamics is of interest to engineers concerned with design of light weight body armor, safety of nuclear-reactor containment vessels subjected to missile or aircraft impact, protection of spacecraft from meteoroid impact and transportation safety of the hazardous materials. The problem of projectile impact on metallic plates has widely been studied in the literature. However, as the problem is highly complex and nonlinear and involves various important parameters which have significant affect on the efficiency of projectile as well as ballistic resistance of the target therefore it requires more investigation. The direction of present study was set after a thol'ough review into literature. It was found that the numerical simulation of projectile impact on metallic plates is still at earlier stages and therefore three dimensional numerical simulations have been performed to predict the behavior of metallic targets subjected to projectile impact. In the present investigation blunt, ogive and hemispherical nosed projectiles have been impacted on 1100-HI2 aluminum target plates at 15°, 30° and 45° obliquity. Moreover, conical nosed projectiles have been impacted on 12 mm thick monolithic steel plates as well as double layered steel plates of 6 mm thickness at 0°, 15° and 30° obliquity. Impact velocity of the projectiles was varied and the effect of obliquity on the ballistic resistance of the target was studied. Effect of projectile nose shape on the deformation behavior of the target was also investigated. Both geometric and material nonlinearities have been taken into account. The analysis has been performed using Johnson-Cook flow stress and fracture model. Finite element code ABAQUS/Explicit has been used to carry out the analysis of 3D models prepared on ABAQUS/CAE. The computational time of each analysis varies from twelve to ninety six hours, depending upon element type, size, number of elements and contact definitions in the model. Numbers of simulations run here counts over one hundred excluding those used for mesh study. Extensive mesh study has been performed before preparing final models for analysis.