Perforation of 12mm thick steel plates by 20mm diameter projectiles with flat, hemispherical and conical noses: Part I: Experimental study

Structural Impact Laboratory (SIMLab), Department of Structural Engineering, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
International Journal of Impact Engineering (Impact Factor: 2.2). 01/2002; 27(1):19-35. DOI: 10.1016/S0734-743X(01)00034-3


Projectiles with three different nose shapes (blunt, hemispherical and conical) have been used in gas gun experiments to penetrate 12 mm thick Weldox 460 E steel plates. Based on the experimental results, the residual velocity curves of the target material were constructed and compared. It was found that the nose shape of the projectile significantly affected both the energy absorption mechanism and the failure mode of the target during penetration. The ballistic limit velocities were about equal and close to 300 m/s for hemispherical and conical projectiles, while it was considerably lower for blunt projectiles. Blunt projectiles caused failure by plugging, which is dominated by shear banding, while hemispherical and conical projectiles penetrated the target mainly by pushing the material in front of the projectile aside. Also, the residual velocity curves were influenced by nose shape, partly due to the differences in projectile deformation at impact. The experimental study, given in this part of the paper forms the basis for explicit finite element analysis using the commercial code LS-DYNA presented in Part II of the paper.

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    • "Finally, the fracture is propagated through the necking circle while the indenter pushes the plate. For specimen C20 (Fig. 5b), the indenter provokes a local shear ring at its perimeter which is named shear circle or shear banding [8] [9]. These specimens suffer small local indentation and plastic deformation outside the shear circle. "
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    • "The ballistic limit velocity of a target plate is severely affected by the nose shape of the projectile under the given impact conditions. Regarding the targets discussed in [11] [12], the hemispherical and conical projectiles gave a ballistic limit velocity close to 300 m/s; whereas, for blunt projectiles it was considerably lower, i.e. 185 m/s. Generally, it may be concluded that the effectiveness of a threat is governed by many parameters depended on given impact conditions, a target material, its thickness and a projectile nose shape. "
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