Low Velocity Impact Response of Resin Infusion Molded Foam Filled Honeycomb Sandwich Composites

In this study the low-velocity impact and post-impact response of low-cost resin infusion molded sandwich composites utilizing a foam filled honeycomb core with graphite and S2-glass fabric facesheets (skins) has been investigated. The foam filled honeycomb core provides combined advantages of the traditional foam core and honeycomb sandwich composites in that it possesses high shear and bending stiffness, and cell wall stability. The low velocity impact response of 101.6 mm x 101.6 mm sandwich plates is studied at five energy levels representative of damage initiation and propagation. The low velocity damage is correlated to ultrasonic C-scan images, vibration resonance frequency and optical microscopy observations. The results indicate that the damage tolerance is enhanced by the foam filled honeycomb core and that load required to initiate damage is independent of the facesheet type for any specific core/facesheet thickness. The sandwich composites with S2-glass facesheets are found to possess more damage tolerance as compared to the graphite facesheets.