Experimentally-Determined Plastic Wave Velocities in Polycarbonate (Lexan) (Striker Velocity 1071 Ft/Sec to 1810 Ft/Sec)

摘要

A previously-reported experimental system for determining the large axial strains, surface rotations, strain rates, and plastic wave velocities during axial impacts at striker velocities up to 2000 ft/sec has been further developed, and is used to investigate the behavior of polycarbonate (Lexan) under high-speed impact. The system employs in-surface diffraction grating strain transducers illuminated with a pulsed ruby laser, with the strain-surface rotation-time-dependent diffraction pattern recorded by high-speed streak cameras. Strain-time and plastic wave velocity-strain data are presented for axial impacts of polycarbonate rods at striker velocities ranging from 1071 ft/sec to 1810 ft/sec. Strains in excess of 20 percent with strain-rates in excess of 16,000/sec have been recorded, as well as wave velocities to 7500 ft/sec. (Author)