Ballistic impact analysis of balsa core sandwich composites

This work investigates balsa core sandwich composites with thin carbon fiber skins subjected to single and multi-site sequential ballistic impacts. For the sandwich composite composed of core and facesheet thicknesses of 0.95 cm and 0.25 mm respectively. The ballistic limit was determined to be 96 m s−1, indicating that it was capable of withstanding impacts from small projectiles such as, secondary debris from blast, hurricane, tornado and foreign object debris from roads and runways. The visual inspection and non-destructive evaluation (NDE) tests showed that the damage was relatively localized. A neat perforation was observed on the strike side facesheet whereas the back facesheet indicated greater spread of damage. The effect of prior damage in terms of residual and absorbed energies became more pronounced as the number of impacts increased. Damage areas were measured in order to quantify the extent of visible failure and/or perforations, while NDE tap testing was implemented to extract the information regarding interfacial damage.