Title: Composite Repair Process for Adhesively Bonded Joints

Authors: Sarah B. Cox, Susan E. Danley, J. Ranae Wright, Alan T. Nettles, William E. Guin, and Kenneth N. Segal

DOI: 10.33599/nasampe/c.19.0696

Abstract: The National Aeronautics and Space Administration (NASA) Composite Technology for Exploration (CTE) project is chartered to advance lightweight joint concepts for Space Launch System class structures. These structures are highly loaded, up to 8 meters in diameter, and enable NASA's exploration to the Moon, Mars and beyond. In support of this project, a study was performed on damage and repair of composite lap joints adhesively bonded to composite sandwich panels. Composite bonded repair development is important for the supportability and maintainability of composite structures. Qualified repairs are critical for launch vehicles and spacecraft that are in final processing to ensure timely and successful flights. Some of the challenges of performing a repair at the launch site is limited access due to both the assembled configuration and platform access to the vehicle, and working in an uncontrolled environment. Although composite repairs are common on aircraft, aerospace structures have structural and thermal profiles which are different than aircraft and require different considerations. For both aerospace and aircraft, adhesive bonding is still very restricted due to concerns with the durability and reliability of a bond compared to bolted joints, including for repairs. This is due to the sensitivity of the bonding process, including adequate surface preparation and proper adhesive curing. NASA does not currently have specific requirements or a standard repair manual for composite bonded repairs. This study documents the results of the impact damage testing and repair process used on the bonded joints. Additionally, the critical requirements and process controls that are needed to perform high quality repairs at the launch site are discussed.

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Conference: CAMX 2019

Publication Date: 2019/09/23

SKU: TP19-0696

Pages: 15

Price: $30.00