An SHM System for Detecting Corrosion Damage in Aging Aircraft

Abstract

Safety, reliability, and sustainment costs are of great concern for aging aircraft. With the many aircraft within the Air Force becoming older there is a need to inspect for corrosion in metallic aircraft structures. A major drawback of conventional NDI methods of inspection is that access to at least one side of the structure is required. This can require that the aircraft be removed from service and the structure disassembled for inspection, which can lead to a host of additional problems. Recent advances in structural health monitoring (SHM) have enabled new developments to enhance current NDI methods to facilitate the inspection of structural components that are difficult to access. Acellent® Technologies has developed SHM systems utilizing permanently installed sensor layers, off-board data acquisition hardware, and software for data analysis and 3D display of diagnostic results. This paper discusses the results of two Phase II SBIR projects performed by Acellent for the USAF to develop a method to inspect for corrosion damage in areas that are difficult to access without disassembling aircraft structure. The two projects were focused on detecting stress corrosion cracking (SCC) on KC-135 structure and pitting corrosion damage in multilayered structural components, such as the XW155.024 chord of the F-15. This paper discusses the challenges involved in the development and transition of this technology including issues concerned with installation of the sensors and design and testing of a new portable handheld device for data acquisition and analysis. Results of the validation testing conducted with the system on simple and complex components will be discussed along with practical issues concerning the implementation and use of the system on aircraft structures.