Fiber-Optic-Based Quality Control of Aerospace CFRP Structures

This study proposes an "advanced smart quality assurance" concept to monitor the curing process of carbon fiber reinforced plastic (CFRP) and assure its cured quality. The authors embedded fiber Bragg grating (FBG) optical sensors in the inter-laminar toughening layer of aerospace-grade CFRP laminates to monitor the local residual strain depending on applied cure pressure. Inter-laminar fracture toughness was then evaluated from double cantilever beam (DCB) tests. A good correlation was obtained between the residual strain value and the fracture toughness, demonstrating that the proposed CFRP quality assurance method is effective to manufacture highly-reliable aerospace CFRP structures.