Penetration and failure of lead and borosilicate glass against rod impact

This paper presents the experimental design and results for gold rod impact on DEDF (5.19 g/cm³) and Borofloat (2.2 g/cm³) glass by visualizing simultaneously failure propagation in the glass with a high-speed camera and rod penetration with flash radiography. At a given impact velocity, the velocity of the failure front is significantly higher during early penetration than during steady-state penetration of the rod. For equal pressures but different stress states, the failure front velocities determined from Taylor tests or planar-impact tests are greater than those observed during steady-state rod penetration. The ratio of average failure front velocity to rod penetration velocity decreases with increasing impact velocity (v_p) in the range of v_p=0.4–2.8 km/s. As a consequence, the distance between the rod tip and the failure front is reduced with increasing _vp$v_{\mathrm{p}}$. The Tate term R_T increases with impact velocity.