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

Electromagnetic-mechanical repair patch of radar-absorbing structure with electroless nickel–plated glass fabric damaged by lightning strike

“…The scarf length considering the defined repair length to be 61.6 mm, and the scarf ratio is 1/20, as this exhibits a high mechanical recovery rate. 32 The diameter of the scarf area is 209.2 mm for the outermost electroless nickel-plated glass/epoxy (t nickel-plated glass/epoxy = 0.351 mm) and the glass/epoxy (t glass/epoxy = 2.730 mm) layers. Figure 9(a) summarizes the EMRP process for the post-lightning specimen #1 radar-absorbing composite panel.…”

“…Conventionally, the adhesive bonded repair method is preferred for repairing composite structures damaged by impacts such as lightning strikes, hailstones, and bird strikes, as it provides high structural integrity, a high load-bearing capacity, and a lower stress concentration in the as-designed structure. 25–34 The most preferred adhesive bonded repair technique is the internal scarf patch-bonded repair technique as it offers high strength and desirable stiffness recovery rate, while maintaining the low-weight and aerodynamic smoothness of the aircraft without changing the surface profile and sequence of the plies. 25,35,36 In this paper, we propose an EMRP method based on a scarf patch to repair lightning strike damage to the radar-absorbing structure with electroless nickel plating to preserve the electrical continuity to achieve stealth requirements related to maintaining electromagnetic absorption performance while maintaining structural integrity.…”

Bonded flush repairs for aerospace composite structures: A review on modelling strategies and application to repairs optimization, reliability and durability

“…Thus, the weakest part of a scarf repair is not always the repaired region. In some shallow configurations [37], failure occurred by simultaneous debonding of the repair and fracture of the parent laminate near tabs. In the field of composite joints and repairs, CFRP woven fabric laminates adherends have been less studied than UD CFRP adherends.…”

Injection repair of CFRP using a multi-Wall carbon nanotubes-modified epoxy resin: Flexural and compression behavior

“…[1][2][3] Further, the delamination can be susceptible to low-velocity impact, which can occur during in-service environments such as tool drops, bird strike, service vehicle collisions, hail, lightning strike, and runway debris. [4][5][6] When subjected to external loads and stress concentration in composite structures, which could be induced in the main characteristic of failure modes can be in the form of inter-laminar damages such as matrix-cracking, interfacial deboning, fiberbreakage, and delamination, usually named barely visible impact damage (BVID) based on their inherent non-homogenous and anisotropic material properties (e.g., projectiles and impact energy levels). [7][8][9] Moreover, when propagating the crack tips of BVID at the around fiber, damage initiation can result in further damage related to delamination and degradation of their mechanical properties related to stiffness and compressive strengths.…”