Aligned recycled carbon fiber (rCF)/polyetherimide (PEI) tapes are a promising material for lightweight aerospace thermoplastic composite structures with reduced environmental impact, provided that their directional properties can be translated into robust components. To assess the viability of rCF/PEI for aircraft interior applications, this study tracks the development of the “Eco Bracket” across four key stages: sustainability screening, coupon characterization, microstructural interpretation, and application-level structural assessment. A project-level life-cycle assessment compared an Additive Fusion Technology (AFT) rCF/PEI bracket with cast and milled aluminum routes and yielded a short-term climate impact of 0.678 kg CO₂-eq for rCF/PEI, representing a significant reduction compared to 5.1 kg CO₂-eq for cast aluminum and 20.9 kg CO₂-eq for milled aluminum. Coupon testing characterized the anisotropic mechanical response of the rCF/PEI tape, including the elastic moduli and strengths under axial and transverse tension, in-plane shear, and axial and transverse compression. Scanning electron microscopy of a representative fracture surface showed a rough, fiber-dominated morphology with exposed fiber bundles, pull-out, and local variations in matrix coverage, supporting the interpretation that consolidation and local wet-out quality govern the transfer from coupon capability to component performance. At the application level, the manufactured rCF/PEI bracket achieved a peak load of 3517.6 N, corresponding to 93% of the strength of an industry-standard polyetherketoneketone (PEKK) reference bracket, and failed in the fastener-hole region predicted as critical by the finite element model. The combined results indicate that aligned rCF/PEI tapes can deliver mechanical properties consistent with the design requirements of aircraft interior brackets, while process robustness, fiber-path fidelity, and local consolidation quality remain the key barriers to repeatable component performance.

The increasing availability of recycled carbon fibres (rCFs) from manufacturing waste and end-of-life composite structures offers new opportunities for sustainable, high-performance composites. However, the discontinuous nature of recycled fibres requires efficient alignment and consolidation. In this study, highly aligned discontinuous carbon fibre tapes were manufactured from recycled carbon staple fibres and bio-based polyamide 11 (PA11) fibres using a textile-based processing route and compression moulding. Two material systems containing nominal fibre mass fractions of 50 wt.% and 70 wt.% rCF were investigated. The resulting laminates were characterised in terms of fibre volume content (FVC), fibre orientation distribution, and mechanical performance. FVC of up to 56.72 vol.% were achieved for the 70 wt.% rCF material. Tensile testing revealed a significant increase in stiffness and strength with increasing fibre content, reaching values of 48.1 GPa and 866 MPa. The longitudinal compression modulus and the in-plane shear modulus showed similar trends, while the transverse tensile strength and compressive strength remained strongly influenced by local defects and fibre–matrix interactions. A 2D mesoscopic image analysis demonstrated a pronounced preferential fibre orientation, with approximately 69% of the analysed fibre regions aligned within ±10° of the dominant fibre direction. The derived alignment coefficient η₀ correlated well with the tensile modulus, confirming the strong influence of mesoscopic fibre architecture on mechanical performance. The results demonstrate that the combination of bio-based PA11 and oriented rCF, enabled through textile-based alignment technologies, provides a promising pathway towards sustainable lightweight composite structures.

Re-aligned recycled carbon fiber (rCF) yarns provide a complementary architecture to aligned rCF tapes, enabling load-path-oriented reinforcement placement with potential for automated near-net-shape preforming and three-dimensional formability. This study investigates hybrid rCF/polyamide 11 (PA11) wrap yarns produced through roller carding, hollow-spindle wrap spinning, tailored fiber placement (TFP), and consolidation. Two rCF/PA11 yarn formulations with nominal fiber/matrix mass ratios of 72/28 and 80/20 were developed, yielding fiber volume fractions of 54.4 and 58.5 vol.%, respectively. Mechanical characterization focused on UD coupon testing under axial tensile, transverse tensile, and shear loading. For the rCF/PA11 72/28 and 80/20 formulations, longitudinal tensile testing yielded moduli of 57.8 ± 4.2 and 64.3 ± 6.3 GPa and strengths of 920 ± 41 and 815 ± 86 MPa, respectively. The 72/28 material additionally exhibited an in-plane shear modulus of 1.87 ± 0.03 GPa and shear strength of 48.7 ± 1.4 MPa. Relative to the previously reported aligned rCF/PA11 tape laminates at a comparable fiber volume content, albeit with distinct processing machinery, the 72/28 yarn laminate showed higher longitudinal modulus and longitudinal strength but substantially lower transverse and shear properties, suggesting a possible architectural trade-off associated with discrete yarn lanes, helical wrapping, and TFP preforming. A conrod-shaped preliminary structural benchmark manufactured from rCF/PA11 72/28 sustained 11.3 ± 0.5 kN at a mass of 23.0 ± 1.0 g, corresponding to a 71% higher specific load capacity than the aluminum reference. Proof-of-concept thermoforming of three double-curved shell demonstrators confirmed the capability of the yarn-based preforms to form complex three-dimensional geometries, although local fiber alignment defects highlighted the need for improved draping control. A screening life-cycle assessment estimated 0.42 kg CO₂-eq per rCF/PA11 benchmark part, representing reductions of approximately 63% relative to the virgin-CF/PA12 stretch-broken yarn route and 52% relative to virgin-CF/epoxy routes. The results demonstrate the potential of rCF/PA11 wrap yarns as high-fiber-content textile intermediates for load-path-oriented TFP preforming and subsequent three-dimensional thermoforming.