Hollow material
Aerospace engineers at the University of Bristol have developed a radical new technique for a self-repairing aircraft. Dr Ian Bond, who led the project, explains, ‘We’d been looking at ways of creating hollow fibres for a number of years’.

The team had also been investigating biomimetics, looking at how a technology could replicate nature. ‘We thought, “we have a structure with the fibre but let’s put something inside the fibre that acts like blood and heals structures.”’ The key is the fibre-reinforced polymer material.

Resin ‘bleeds’ out
So, if a hole appears in the aircraft, a resin ‘bleeds’ out, hardens and seals it, enabling the plane to continue until it can be fully repaired if necessary. The technique is not intended to repair major damage, but day-to-day wear and tear. ‘If there is a hole in the structure you’d hope that people would notice it’, says Bond. ‘But sometimes there is subtle damage that is difficult to see, caused by things such as dropped tools, runway debris and vehicles driving into aeroplanes. This type of damage worries the airlines because if it isn’t repaired, it could get worse’.

Wider applications
Bond says that his team have been investigating the idea since 2001 and 2002, ‘In the University and the surrounding area there’s a pool of engineering and research talent to draw on. ‘We are in the centre of the aerospsace industry,’ says Bond. ‘We have Airbus, Rolls Royce, Westland helicopters, all within an hour’s drive.’

The team are hoping to apply the technique to areas of the plane that suffer wear and tear through constant use, such as doors, hatchways and fuel-filling points on the wings. But the applications are wider. Bond’s team have looked at using the technique on wind turbines for example. ‘Wind turbines are usually in inaccessible areas, either onshore of offshore. Ideally you don’t want to have to keep repairing them’.  The lightweight fibre material used in the new technique may also mean that in the future we may see lighter more fuel-efficient planes.