Nondestructive Testing and Evaluation of Composite Aerospace Structures

Abstract

There is a broad range of approaches and technologies used for nondestructive testing and evaluation (NDT&E) of composite aerospace structures. The aim of this article is to provide an overview of the most common measurement methods used in the aircraft manufacturing sector for nondestructive detection of internal defects in carbon fibre composite structures, as well as signal and image processing techniques available for computer-assisted evaluation. The problems and challenges faced by NDT&E are first explained in terms of typical composite aerospace components, typical defects, and general inspection requirements. Four most common production NDT techniques are then presented in detail, covering principal aspects of ultrasound, radiography, shearography, and thermography in terms of their operating principles, performance, and applications to composite aerospace components. This is followed by signal processing methods for NDT signal enhancement, detection, and restoration as well as image processing methods for mosaicking of multiple NDT images, registration with component CAD model, fusion of multimodality NDT images, defect visualisation, and automatic defect detection. Finally, future NDT&E trends are highlighted based on current technology progress.