BEHAVIOUR OF STRUCTURAL ELEMENTS UNDER HIGH STRAIN RATE

Abstract

The present study is based on the response of metal plates subjected to high strain rate. The span diameter of 1 min thick 1100-H12 aluminum target and 12 mm thick Weldox 460E steel targets was varied and its effect there on the ballistic limit was obtained.lmm thick 1100-H12 aluminum target was impacted by ogive nosed projectile and 12 mm thick Weldox 460E steel target was impacted by conical nosed projectile with nose angle 33.40.1 mm thick 1100-H12 aluminum targets of eight different span diameters i.e 95 mm, 190 mm, 285 mm, 380 mm, 475 mm 570 mm, 665 mm and 760 mm were impacted by ogive nosed projectile of 19 mm diameter and 52.5 grams mass. 12 mm thick Weldox 460E steel targets of eight different span diameters i.e 100 mm, 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm and 800 mm was impacted by conical nosed projectile of diameter 20 mm and 197 grams mass with nose angle of 33.4°. Three-dimensional numerical simulations were carried out with the help of ABAQUS/Explicit finite element code. A variation in the target span can have considerable influence on the resistance of target if all the other parameters such as target thickness, projectile nose shape, impact velocity and angle of incidence kept constant. The impact velocity of projectiles was varied and the ballistic limit oftarget was obtained. The target span was found to have significant influence on the ballistic limit. It was found that for a given projectile the ballistic limit increased with an increase in the target span. The results of the present study were compared with the experimental results available . in literature. A close correlation between the present three-dimensional numerical simulations and previous experimental results was found for both the cases studied. Failure mode of the target was also found to be affected by the nose shape of the projectile as well as the target span diameter. Johnson-cook constitutive model which was incorporated in ABAQUS/Explicit finite element codehas been employed in the modeling of the present problem.