Hypervelocity impact on carbon fibre reinforced plastic/aluminium honeycomb: comparison with Whipple bumper shields

Normal and oblique incidence hypervelocity impact tests (velocity range 4-6 km s(-1)) were carried out to determine the ballistic limit of a 1.6 mm carbon fibre reinforced plastic facesheet bonded to 45 mm aluminium honeycomb core, as typically used in Low Earth Orbiting spacecraft. The internal honeycomb damage was determined as a function of the impactor parameters. The ballistic limit data showed a strong dependence with impact angle. The internal honeycomb damage was found to be independent of impact angle for constant impact energy for Theta<50 degrees. An empirically-determined damage equation linking honeycomb damage to impact energy was developed. For the highest impact energy perforating impacts, the debris cone angles for the primary and secondary debris cones were determined. As the impact angle increased, the centre of the damage cones rotated away from the line of flight. The data have been compared with the ballistic limit curve defined by the modified Cour-Palais aluminium Whipple bumper equation and show broad agreement with the equation predictions. A reduced value of the rear facesheet thickness is required to bring the normal and 15 degrees incidence data into agreement with the ballistic limit curve.