3D characterisation of carbon fibre reinforced composite microstructure via x-ray computed tomography

Carbon fibre reinforced polymer (CFRP) composite materials possess highly desirable physical and chemical properties and are now commonly utilized in many structural components in aerospace, civil engineering, military, as well as in motorsports and other competition sports. Structural defects in CFRPs are often caused by insufficient fibre impregnation and non-optimized process parameters during the manufacturing process. These defects can severely compromise the expected performance from CFRPs [1], [2]. Understanding the characteristic geometry and shape of these defects as well as their spatial distribution within the three-dimensional (3D) CFRP's structure (matrix and fibres) can provide insight into the origin of their formation and can enable optimization of the fabrication process. In this study, a state-of-art 3D X-ray microscopy technique by computed-tomography (micro-CT), combined with tomographic volume analysis and visualization tools, has been utilized to study a suite of highly different CFRPs. Using both proprietary and open-source software, the main constituent materials (fibres, matrix/resin, voids) of the samples have been identified and segmented; the distribution of each material is then mapped in 3D and the respective volume fractions are quantified. As a case study, segmented voids have been clustered into two different families based on their shape and preferential location within the material micro-structure of one particular sample.