Composites are increasingly used for major structural items where component thicknesses can be very large - greater than 100mm - and have very large aspect ratios (eg for aerospace and wind turbine applications). The attenuative nature of composites can render ultrasonic techniques unusable. X-ray computed tomography (CT) offers solutions, but traditional methodologies do suffer a number of limitations: they require a full 360o rotation of either the object under test or the radiographic equipment in order to obtain a complete dataset necessary for volumetric image reconstruction, which is not always possible. The large aspect ratios also produce beam hardening or other artefacts in the reconstructed data, obscuring internal features.
This project aims to investigate the use of multiple X-ray energy exposures for CT data capture and reconstruction in order to increase the tolerance of wide aspect ratio components. Research will also be carried out to apply multi-energy techniques to advanced tomographic methodologies such as laminography and tomosynthesis, which can overcome some of the physical limitations in artefacts arising from monochromatic X-ray absorption model reconstruction.