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Publication - Dr Andrew Lawrie

    3D characterisation of fibre orientation and resulting material properties


    Smith, RA, Roldo, G, Mukhopadhyay, S, Lawrie, A & Hallett, SR, 2013, ‘3D characterisation of fibre orientation and resulting material properties’. in: 52nd Annual Conference of the British Institute of Non-Destructive Testing 2013, NDT 2013. British Institute of Non-Destructive Testing, pp. 198-209


    Conformance of ply lay-up and local fibre orientation to design is critical in ensuring the performance of composite structures. It has been shown that even very small misalignments of fibres can cause a significant knock-down in strength and stiffness in the important stress directions. A new ultrasonic method has been developed for non-destructive mapping of both out-of-plane ply wrinkling and in-plane fibre waviness. The resultant 3D map of fibre orientation can form the basis of a 3D finite-element model to determine mechanical properties of the actual as-built structure and such a model is demonstrated here. This capability is important not only at manufacture but also in service for mapping material surrounding a defect in order to design a composite repair and then to confirm the integrity of the repair. In the military environment, information about the ply lay-up is not always available for assisting in the design of a repair. Ultrasonic determination of ply lay-up and the thicknesses of the plies will allow customised in-service repairs. Extensive validation work has been carried out on the technique which can be applied to full-waveform ultrasonic data captured in a variety of formats from either single-element or phased array acquisition systems. A programme has commenced to create 3D finite-element meshes and import this 3D fibreorientation information into the cells to determine the stiffness axes. The capabilities, limitations and current status of the technique are presented here.

    Full details in the University publications repository