In situ resin‐injection approach for repairing barely visible impact damaged carbon‐fiber reinforced epoxy laminates: Optimizing the repair parameters using Taguchi method

Abstract

AbstractA new portable resin injection device has been developed to repair barely visible impact damage (BVID) in carbon fiber reinforced polymer (CFRP) laminates. Repair was conducted on damaged 16‐ and 24‐ply laminates at two different ambient pressures, that is, atmospheric pressure and vacuum, using three different adhesive types, that is, neat epoxy, epoxy blended with respective halloysite nanotubes (E1HNT) and carbon nanotubes (NF100). The repair effectiveness was assessed by infrared thermography and in‐plane compression testing. All damaged laminates suffered significant degradation in fracture properties as compared to pristine laminates. According to Taguchi method, the main factor affecting the repair efficiency is the laminate ply number. The findings revealed that the optimal repair parameters corresponds to using neat epoxy or E1HNT in vacuum could restore the elastic properties and using E1HNT adhesive at atmospheric pressure could restore the fracture properties of damaged 16‐ply laminate after repair. Regardless of repair parameters, the repair efficiency for the mechanical properties of 24‐ply laminates revealed minimal restoration to the laminate pristine conditions after repairing the damaged laminates due to the complexity of BVID for allowing the adhesive to infiltrate and filled the crack structures. The choice of repair parameters was discussed based on the effectiveness of restoring elastic and fracture properties.