Composite aerospace structures that emit light when damaged could be the outcome of a five-year UK research programme that began this month.
A structure would contain, within its hollow carbonfibres, nanoparticles of minerals that give off orange or yellow flashes when damaged, a property known as triboluminescence. They would emit light when there is a fracture through the material, making it easy to spot internal damage. Until now it has been difficult to detect internal defects in composites.
Dr Ian Bond, lecturer in aerospace engineering at the University of Bristol, is principal investigator on the project. "Getting the mineral crystals into the hollow fibre is difficult. A fibre is only eight microns wide. We are using liquids to carry the particles into glassfibre at the moment. Nanoparticles are interesting because of their size," he says.
In theory, the light would be carried by embedded optical fibres to the structure's surface. The work will build upon triboluminescent damage sensor research previously carried out by the UK government's former Defence Evaluation and Research Agency (DERA).
Up to 1999, the DERA developed triboluminescent materials with thermal and chemical properties that enabled them to be incorporated into composites. Another potential use of an embedded optical fibre is as a sensitive strain gauge. The five-year research programme will also aim to develop plastics that "bleed to seal fractures" and design anti-delamination fibre geometries. The project will start this month and end in June 2009, and cost £360,000 ($667,000). The work is supported by the UK's Engineering and Physical Sciences Research Council with a grant of £230,000.
Source: Flight International
