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 ca rbon fibre reinforced plastic facesheet bonded to 45 mm aluminium honeycomb core, as typically used in Low Earth Orbiting spacecraft. The internal hon eycomb damage was determined as a function of the impactor parameters. The ballistic limit data showed a strong dependence with impact angle. The inte rnal honeycomb damage was found to be independent of impact angle for const ant impact energy for Theta<50 degrees. An empirically-determined damage eq uation linking honeycomb damage to impact energy was developed. For the hig hest impact energy perforating impacts, the debris cone angles for the prim ary and secondary debris cones were determined. As the impact angle increas ed, the centre of the damage cones rotated away from the line of flight. Th e data have been compared with the ballistic limit curve defined by the mod ified Cour-Palais aluminium Whipple bumper equation and show broad agreemen t with the equation predictions. A reduced value of the rear facesheet thic kness is required to bring the normal and 15 degrees incidence data into ag reement with the ballistic limit curve. (C) 1999 Elsevier Science Ltd. All rights reserved.