Title: Process Control of Laser Surface Treatment for Robust Bonding of Composite Aerostructure

Authors: Eileen O. Kutscha, Rodolfo I. Ledesma, Frank L. Palmieri, Kay Y. Blohowiak, John W. Connell

DOI: 10.33599/nasampe/s.21.0558

Abstract: The United States Federal Aviation Administration (FAA) highly recommends the use of process control for fabrication of structurally bonded composite joints for aircraft structure as outlined in guidance circular AC-107B. Surface preparation of composites, which includes peel ply, manual or automated grit blast and sanding, and energetic methods including plasma and laser ablation, is considered to have a high impact on bond performance based on a thorough risk analysis of the bonded joint fabrication operation. The surface preparation step could be made more robust with better process control. Quantification of the surface preparation operation has been a challenge due to the lack of consistent correlation between surface analysis tool outputs and the surface preparation presence or levels. Surface analysis tools for color, gloss, Fourier transform infrared spectroscopy (FTIR), and optically stimulated electron emissions (OSEE) have been previously identified to have the ability to quantify the level of sanded surface preparation. These were investigated again here for detection of laser surface preparation with success. Additionally, an emerging method in the aerospace field, laser induced breakdown spectroscopy (LIBS), also demonstrated the ability to quantify laser surface preparation. Threshold limits were defined enabling the surface analysis tools to be used for process control of the bonding operation. It is recommended to define these limits prior to establishing a certification test plan to reduce the risk in bonded joint fabrication upstream prior to initiating time consuming and costly certification test plans. This will lead to the eventual reduction in timeline to certify aircraft with bonded composite structure and achieves the main goal of the National Aeronautics and Space Administration (NASA) Advanced Composites Project (ACP).

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Conference: SAMPE NEXUS 2021

Publication Date: 2021/06/29

SKU: TP21-0000000558

Pages: 20

Price: FREE