Abstract
This work focuses on the non-destructive identification of delamination in layered structures utilizing the X-ray phase contrast effect. This effect naturally occurs on sharp edges, material interfaces and fine textures, and can be retrieved from radiographic data even without any grating in special cases, as will be demonstrated for the layered carbon fibre reinforced plastic composites used in the aerospace industry. Such delamination can be described as the local disbonding of composite layers, which often occurs due to the cyclic loading of the structural elements while in service. Such a flaw may significantly decrease its bearing capacity, and therefore periodic non-destructive inspection is needed. Aside from ultrasound inspection, which provides limited resolution and detectability, X-ray imaging and tomography is widely used in practise. Nevertheless, the identification of delamination may be difficult utilizing X-ray computed tomography, as delaminated faces may remain in contact — the defect has negligible volume. On the other hand, the distance between faces is not relevant for X-ray phase contrast imaging. In addition, access to the structural elements is often limited for X-ray imaging. For shaped parts, it will be shown in this work that limited access is not as critical a problem in comparison with standard computed tomography.