Experimental investigation of single and repeated impacts for repaired honeycomb sandwich structures

Single and repeated impact behaviors of repaired honeycomb sandwich structures which are used in cargo panels at A319/A320/A321 Airbus were examined. Firstly honeycomb sandwich composites with detected impact damages which are in the limits of Aircraft Maintenance Manual and Repair Manual were repaired according to these manuals. Preliminary single low-velocity impact loadings were performed for original and repaired samples in order to find the energy limits which were ranged from fully elastic energy level to perforation energy level. At low-velocity single impact loadings, impact properties and damage mechanisms which occurred at both surface and internal parts of the materials were discussed from force- deflection (F-D) curves. In the second part, low-velocity repeated impact tests were performed with the determined impact energy levels. Repeatedly impact loading properties were also discussed with F-D curves. Impact damages which occurred in front and rear faces of composite structures were determined with digital camera. According to experimental results it was determined that impact behavior of repaired honeycomb composites is sufficient to be used in aircrafts.