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Session: Session 11: Repair strategies
Session starts: Thursday 16 April, 15:20
Presentation starts: 15:20
Room: Main

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Arjun Chandra Shekar (École de technologie supérieure)
Redouane Zitoune (Institut Clément Ader (ICA), Toulouse, France)
Lucas A. Hof (École de technologie supérieure)

Abstract:
In the aerospace field, the repair of composite structures remains among the least automated operations within the production and maintenance chain. This process is typically performed manually, relying on operator expertise, subjective inspection, and costly component replacement. Additionally, manual milling during material removal generates hazardous particulate matter, posing health risks to operators. With the growing adoption of digital manufacturing, there is a clear need to transition such repair operations toward greater automation. Addressing this need, the present study focuses on the bonded repair of continuous-fiber thermoplastic composites and introduces a reverse-engineering-driven circular repair framework designed to establish the foundation for progressive automation in composite maintenance. Following damage detection, the proposed workflow integrated robot-assisted damage removal, human-operated surface digitization, geometric reconstruction, and additive manufacturing within a digitally assisted environment, thereby enhancing repeatability, precision, and sustainability while aligning with circular manufacturing principles. The process began with controlled machining of the damaged region to remove the defect while maintaining the structural continuity of the surrounding laminate. The machined cavity was captured through high-resolution 3D scanning, and the acquired point-cloud data was processed through reverse engineering techniques to generate a precise digital model. This digital representation enabled the creation of a tailored repair patch that seamlessly matched the cavity geometry. With this original approach, the gap between the patch and the parent geometry, arising from machining of the damaged zone influenced by the residual stress was reduced. The patch was fabricated via material extrusion additive manufacturing (MEX) using continuous carbon fiber thermoplastic feedstock and subsequently adhesively bonded to the parent substrate using an epoxy film adhesive cured under controlled temperature and pressure conditions to restore geometric integrity and load-transfer capacity. The fabricated patches demonstrated precise geometric conformity with the parent structure, validating digital repair accuracy. Although the present workflow includes partial manual operations, its digitally linked stages establish a data-driven foundation for future automation in repair processes. By restoring damaged regions using customized MEX-fabricated patches instead of replacing entire components, the framework reduces waste and extends component life, offering a sustainable approach towards automated composite repair within a circular manufacturing framework.