Progress in 3D characterisation and modelling of monolithic carbon-fibre composites

The route to lighter composite aero-structures requires advanced 3D non-destructive characterisation (NDC) methods to provide confidence that the as-built structures conform to the design expectations. Material models can also make use of this type of NDC data, allowing performance prediction of as-built structures and opening new possibilities for accepting components into service, component life prediction and in-service inspection routines. The toolset to achieve such a structural integrity framework is understandably multi-disciplinary and diverse. This paper provides an overview of progress towards this framework. One of the main elements covered is the progress towards measuring 3D fibre orientation, the first material property required to enable material modelling, followed by ply spacing, fibre volume fraction and, in the future, 3D porosity distribution. Following an extensive study of the literature for characterising other kinds of fibrous or textured images (fingerprints, hair, textiles, etc), the most promising methods have been evaluated and compared using ultrasonic and X-ray CT data. This paper also demonstrates the ability to use these 3D fibre orientation maps to construct a finite element model to determine the mechanical properties of the as-manufactured structure.