Advanced, couplant free non-destructive testing system for next generation composite parts - CFLUX

The use of composite materials in aerospace manufacture is accelerating fast, with the most modern aircraft in the world's fleet now more than 50% composite materials. These new-generation aeroplanes are lighter, more fuel-efficient, and so more profitable, as well as significantly reducing CO2 emissions compared to traditional aluminium planes. However, composite materials are much more expensive to produce, partly because they are not yet as well-understood as metals, so the industry spends millions every year slowly inspecting each part for flaws before it is deemed safe enough to take its place in an aircraft, and inspecting composite components is not easy.

Carbon fibre composite is in many ways an ideal material for aerospace construction, being less dense than aluminium, with a greater stiffness-to-weight ratio. It does not corrode and it is less susceptible to fatigue. Carbon fibre components can be moulded directly into their required geometry, reducing the need for vulnerable bonded areas. But there is also the possibility of introducing weakened areas when constructing the material itself - fibres can break or move out of alignment, layers can separate, gaps can open up, and this can all happen invisibly, deep within the internal structure of the material, weakening it and leading to unexpected failure.

Manufacturers need techniques to inspect the internal structure of their carbon fibre components and CFLUX is designed to do just that. The inspiration comes from traditional eddy current non-destructive testing techniques that have been used for aluminium aircraft. These are fast and effective for finding hidden flaws but rely on the good conductivity of metals. Carbon fibre is 1000 times less conductive than aluminium, making eddy current testing impossible, until now.

The CFLUX consortium have developed innovative sensor technology that can give sensitivities 1000 times greater than before, retrieving high-quality, high-resolution signals that were previously unachievable. Not only that, but this technology is tiny, making it easy to develop into multi-sensor arrays that are resilient, flexible and ideal for use in the production-line robotics necessary to really speed up and reduce the cost of the inspection process.

Robotic inspections using CFLUX are expected to be more than 30 times faster than current processes, reducing inspection costs from £1,292 to just £72 for a single 34m2 composite component. This supports the aerospace industry in its drive for safe aircraft that are lighter, more cost-efficient, and have a reduced impact on our environment.