Failure behavior of on-site repaired CFRP laminates

Sonat E., Bakır M., ÖZERİNÇ S.

Composite Structures, vol.311, 2023 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 311
  • Publication Date: 2023
  • Doi Number: 10.1016/j.compstruct.2023.116806
  • Journal Name: Composite Structures
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Communication Abstracts, INSPEC, Metadex, Civil Engineering Abstracts
  • Middle East Technical University Affiliated: Yes


On-site repairs of carbon fiber reinforced polymer (CFRP) composites involve out-of-autoclave curing, which increases the defect density and reduces the mechanical properties. This work aims to understand the strength and the associated failure mechanisms of on-site repaired woven CFRP laminates through experiments and simulations. A series of wet lay-up and prepreg step repaired specimens produced according to standardized aerospace procedures were tested under uniaxial tension. Wet lay-up repair provided a strength recovery of 66%, whereas prepreg repairs maintained 76% of the original strength. Finite element modeling closely predicted the experimentally observed behavior and showed that stress concentrations due to the adhesive-adherent stiffness mismatch are the primary causes of the lowered strength. The findings provide systematic experimental data and an accurate modeling framework to design and implement effective repairs in practice.