A morphing aircraft can be defined as an aircraft that changes configuration to maximize its performance at radically different flight conditions. Morphing structures require a large aspect ratio and area change during flight in order to optimise operational performance. Morphing wings are being developed to mimic bird’s wing movements. Birds have different wing profiles at different points in their flight, where swept wings reduce the drag at higher speeds at flight lift-off and long straight wing profile is better for performance at low loitering speed. Hyper-extensible braided cords have been developed to be used within morphing ‘skin’ materials. The cords use a low-modulus elastomeric core braided around with high-modulus yarns. These cords can be produced with various braid angles, which influence the extensibility of the cords. The higher the braid angle, the greater the extension The braid angle is controlled by the precision pre-tension of the elastomeric component. A computational model for predicting the load-strain behaviour of these hyper-extensible cords has been developed. Opposite to hyper-extensible cords are inextensible cord reinforcement composites, such as toothed timing belts used in car engines, which utilise a combination of reinforcement techniques to guarantee a high quality high strength product. Braiding is an alternate technology for producing cords with potentially superior performance in terms of improved ability to resist unravelling as well as superior interface due to ‘Chinese finger-trap effect.’ Carbon core with varying glass fibre braid have been developed. This led to various braid patterns being formed. A system for mapping braid pattern/topology has been developed. Aswel as the braid pattern, the braid colour patterns can also be produced. This mathematical model involves basic matrix manipulations, which have been proved using the MatLab program. The predicted braid patterns have been compared with actual samples. Being able to model braid patterns is a time and cost effective compared to previous trial and error methods.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:626930 |
| Date | January 2014 |
| Creators | Nawaz, Sabahat |
| Contributors | Potluri, Prasad |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/braided-cords-in-flexible-composites-for-aerospace-and-automotive-applications(94c6d617-d797-46a0-bac2-65d821b0e110).html |
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