The dynamic indentation behavior of steel at large depths of penetration

Abstract

The objective of the present study is to investigate the dynamic indentation behavior of steel plate material when impacted by ogive-shaped projectiles and in particular under indentation conditions involving large depths of penetration (i.e., depth of penetration greater than projectile radius). Toward the above purpose, dynamic indentation of steel plates of thickness 20, 40, and 80 mm have been carried out using projectiles of diameter 6.2 and 20 mm, and over a range of impact velocities so as to attain depths of penetration in the range 1.4 to 3.6 times the projectile radius. The results indicate that the dynamic hardness, the plastic zone size, specific energy consumed in plastic deformation within the plastic zone, and the average plastic strain within the plastic zone increases continuously with increasing values of depth of penetration normalized by projectile radius. Certain subtle differences regarding the nature of plastic deformation between indentation at large and shallow depths of penetration are presented. However, on a macroscopic scale, the indentation mechanisms and processes are broadly similar and show continuity in terms of behavior across the whole penetration depth range.