A SIMULATION-DRIVEN STUDY OF OBLIQUE IMPACT OF OGIVAL-NOSED PROJECTILES ON MILD STEEL ARMOUR PLATES

Abstract

THE PRESENT PAPER DEALS, FOR THE FIRST TIME, WITH A SIMULATION-DRIVEN STUDY OF OBLIQUE IMPACT OF JACKETED OGIVAL-NOSED PROJECTILES ON MILD STEEL TARGET PLATES. THE PREDICTABILITY OF ANALYSIS RESULTS IS VERI¯ED AGAINST TEST RESIDUAL VELOCITIES REPORTED BY EARLIER INVESTIGATORS [7]. THE IMPACT VELOCITIES CONSIDERED HERE ARE IN THE RANGE OF ~800-850 M/S. FINITE ELEMENT MODELLING IS CARRIED OUT BY DISCRETIZING TARGET PLATE WITH SHELL ELEMENTS AND PROJECTILE WITH SOLID ELEMENTS. THE EFFECTS OF STRAIN RATE ON PLATE MATERIAL BEHAVIOUR ARE INCORPORATED USING AVAILABLE DATA ON STRAIN RATE SENSITIVITY OF YIELD AND ULTIMATE STRENGTHS OF VARIOUS GRADES OF STEEL. USING AN EXPLICIT LS-DYNA SOLVER, CONVERGENCE OF RESIDUAL VELOCITY IS SHOWN WITH RESPECT TO PLATE ELEMENT SIZE FOR NORMAL AS WELL AS OBLIQUE ANGLES OF IMPACT. IN ADDITION TO PREDICTING RESIDUAL VELOCITIES, THE CURRENT SIMULATION PROCEDURE IS ALSO ABLE TO REALISTICALLY REPRESENT PLATE FAILURE MODES SUCH AS PERFORATION WITH DISHING, EROSION OF COPPER SHEATH OF HARDENED STEEL CORE PROJECTILE, AND MINIMUM ANGLES OF PROJECTILE RICOCHET FOR PLATES OF DIFFERENT THICKNESSES. THE STUDY CONCLUDES WITH THE PRESENTATION OF A SEMI-EMPIRICAL RELATION, BASED ON THE SHEAR PLUGGING MODE OF PLATE FAILURE, WHICH APPEARS TO PREDICT WELL PROJECTILE RESIDUAL VELOCITIES FOR BOTH NORMAL AS WELL AS OBLIQUE IMPACT.