Different Scale Experiments of High Velocity Penetration With Concrete Targets

In this study, two different scale projectile high velocity penetration experiments with concrete targets that had an average compressive strength of 35 MPa were conducted in order to find the velocity limits and nose erosion properties. We conducted the penetration experiments for the small-scale (48 mm diameter, 195 mm long, 2 kg) and the large-scale (144 mm diameter, 680 mm long, 50 kg) ogive-nose projectiles with the hard steel 4340 whose dynamic compression strength is 2.2 GPa. A 100-mm-diameter powder gun was used to launch the five tests of the 2 kg projectiles with striking velocities between 1100 m/s and 1600 m/s and a 320-mm-diameter Davis gun was used to launch the two tests of the 50 kg projectiles with striking velocities 1100 m/s and 1300 m/s. The experimental results showed that the nose material was missing, indicating an apparent eroding process when the striking velocity exceeded 1400 m/s, where the rigid body penetration made a transition into the elastic-plastic hydrodynamics regime and penetration depth begin to decrease when the striking velocity exceeds 1400 m/s. Furthermore, nose changes and mass loss due to nose erosion did not significantly affect the penetrating ability before rigid body penetration made a transition into the hydrodynamic regimes. In addition, nose erosion was analyzed with SEM surface microstructures, and the SEM image showed that the mass loss of projectiles was due to the shear cracks preceded by adiabatic shear bands.