LAUSR

Abstract Scarf repair method which can get uniform stress distributions and smooth surfaces has emerged as an adequate technique to repair damaged aerospace composite components. However, a prominent problem with the use of scarf-repaired structures is their susceptibility to environmental conditions. This research deals with the failure and reliability analysis of scarf-repaired carbon fiber-reinforced polymer composites (CFRP) before and after aged in hot–wet environment. Scarf-repaired CFRP with different laminate thicknesses was tested to investigate the failure strength and damage modes. The results indicate that the strength reduction of scarf-repaired CFRP varies with the laminate thickness (13.4–7.9%) because of different moisture contents. Fracture observations reveal that the decrease in load-bearing capacity of scarf-repaired CFRP is mainly due to the degradation of adhesive layer. Subsequently, theoretical models based on the distribution function of experimental results were established to predict the safe design strength at different reliability and confidence levels. It is shown that reliability has a greater effect on the safe design strength of both unaged and aged specimens than confidence level. A higher penalty paid to get high-reliability strength (R = 0.99, γ = 0.99) is observed for the unaged specimen, which has a larger coefficient of variation.