Experimental evaluation on compression-after-impact behavior of perforated sandwich panel comprised of foam core and glass fiber reinforced epoxy hybrid facesheets

To study the impact response and compression-after-impact (CAI) behavior of perforated sandwich panels comprised of foam core and glass fiber-reinforced epoxy hybrid facesheets, the hole diameter of specimens is changed in the fabrication via vacuum-assisted resin infusion. Furthermore, low-velocity-impact tests with various impact distances between the impact point and hole are carried out. With the help of the digital image correlation technique, CAI testing is conducted, and the strain evolution of specimens is monitored carefully. The mechanical response history, damage morphology, and compressive process are discussed in detail. The results show that the impact and CAI performance of specimens are weakened because of open holes. Compared with the non-perforated specimen, the maximum force of the specimen with a 6-mm hole and the 5-mm impact distance decreases by 41.21%, and its maximum displacement increases by 38.60%. During the CAI process, in comparison with the impact damage, more significant stress concentration and buckling around the hole are found.