Ultrasound tool makes sense of metal fatigue

A new ultrasound tool, designed to instantly detect metal fatigue and other damage in
aircraft, has been developed at Sheffield University.

A new ultrasound tool, designed to instantly detect metal fatigue and other damage in aircraft, has been developed at Sheffield University.

The instrument, which is designed to be used in conjunction with a new type of airframe, will replace the need for lengthy visual inspections, said Wieslaw Staszewski, lecturer in mechanical engineering who has been working on the technology since 1998.

He said that the technology can be used for offshore structures, gas pipelines, pressure tanks and general infrastructure.

‘We believe we have a well-proven technology and want to develop it. It’s a good technique for damage detection in materials, and is based on acousto-ultrasonic waves, a form of non-destructive testing. Everybody we talk to wants to see the product work.’

The new airframe material contains embedded and surface sensors, known as ‘smart panels’. This material would form the bulk of future aircraft structures. The sensors themselves are piezo-ceramic, and will change their conductivity when they are put under stress or strain.

A wave, induced by the hand-held ultrasound detector, is sent out through the aircraft’s structure. This instantly changes if it encounters any damage.

The signal that is sent back will allow maintenance staff to identify both the location and the type of damage.

‘In metals we can find fatigue, it being the most common cause of failure. And in composites we can detect delamination, another common problem,’ said Staszewski.He is now looking to make the technology commercially viable through a university spin-out company Aphora, which was formed in January.

Aphora’s management team aims to raise £1.5m from venture capitalists during the next four months and is also in talks with a number of aerospace companies.’We have a very specific market with major players and there are many bodies such as the Civil Aviation Authority to deal with. We will need their approval to go ahead,’ said Staszewski.