Mechanical performance and damage monitoring of CFRP thermoplastic laminates with an open hole repaired by 3D printed patches

Thermoplastic laminates are increasingly used in the automotive industry, so it is essential to study convenient and effective repair technologies. In this paper, an adhesively bonded repair method based on 3D printed patches is proposed. Multiple types of patches were fabricated using 3D printing technique and traditional laminate cutting process, respectively. Two stacking sequence laminates including angle-ply and quasi-isotropic were utilized in this study. The mechanical properties of the repaired specimens were tested under tensile loading, and the strain distribution and damage process were monitored by digital image correlation (DIC) technique. The damage characteristics and failure mechanisms are analyzed. The results indicate that the load-bearing capacity of the open-hole laminates can be significantly improved through the repair method. Compared with traditional patches, the 3D printed patches show more excellent repair performance. Moreover, 3D printed patches are easier to manufacture and have a lower cost. This study can provide some insight for the repair of automotive lightweight components manufactured by polymer composites.