A new technique that copies nature's healing processes could enable damaged aircrafts to mend themselves, even during a flight. The technique works on small-scale damage that's not obvious to the naked eye but which might lead to serious failures in structural integrity if it escapes attention. The technique works like this: If a tiny hole/crack appears in the aircraft due to wear and tear, fatigue, a stone striking the plane, etc, the epoxy resin will bleed from embedded vessels near the hole/crack and quickly seal it up, restoring structural integrity. By mixing dye into the resin, any 'self-mends' could be made to show as coloured patches that could easily be pinpointed during subsequent ground inspections, when full repair work can be performed.
This technique has been developed by aerospace engineers at Bristol University, with funding from the Engineering and Physical Sciences Research Council (EPSRC). It has potential to be applied in the fields of aircraft, car, wind turbine and even spacecraft manufacture : wherever fibre-reinforced polymer (FRP) composites are used. The technique involves filling the hollow glass fibres contained in FRP composites with resin and hardener. If the fibres break, the resin and hardener ooze out, enabling the composite to recover up to 80-90% of its original strength - comfortably allowing a plane to function at its normal operational load. The new self-repair technique developed by the current EPSRC-funded project could be available for commercial use within around four year. The technology could make it possible to design lighter aeroplanes leading to fuel savings, cutting costs for airlines and passengers and reducing carbon emissions.