Parametric study on static and fatigue strength recovery of scarf-patch-repaired composite laminates

• Published in: Composite structures 2016-04, Vol.140, p.417-432
• Main Authors: Yoo, Jae-Seung, Truong, Viet-Hoai, Park, Min-Young, Choi, Jin-Ho, Kweon, Jin-Hwe
• Format: Article
• Language: English
• Subjects: Composite; Composite structures; Fatigue strength; Fatigue testing; Fatigue tests; Laminates; Recovery; Scarf patch repair; Static tests; Strength; Strength recovery
• ISSN: 0263-8223; 1879-1085
• DOI: 10.1016/j.compstruct.2015.12.041

Carbon–epoxy composite laminate recovery rates are analyzed with respect to their static and fatigue strengths following local-damage repair using the scarf-patch bonding method. The tensile strength recovery rate is tested for 1.9–11.3° scarf angles (scarf ratios: 1/30–1/5). Static tests are performed for three external-ply overlap lengths and two defect sizes. The fatigue characteristics are identified via fatigue testing of a defect-free specimen and two specimens with different scarf angles. The static test results indicate that the strength recovery rate is significantly lower for scarf ratios of 1/10 or greater. Conversely, 1/20 and 1/30 scarf-ratio specimens exhibit high recovery rates of 79.1% and 83.6%, respectively, compared to the defect-free specimen. The external-ply overlap length and defect-size effects are negligible. For a million-cycle fatigue test, the fatigue strength recovery rates of the 1/20 and 1/30 specimens are 39.7% and 52.1%, respectively, being lower than the static strength recovery rate.