A new technological development from engineers at Bristol University in the UK say they've developed a way to use ultrasonic nonlinear imaging techniques to find cracks and structural weakness in materials used in things like aeroplanes and bridges, which previously could not have been found. They say that could mean things are replaced on time and not overused. Joel Flynn listens in.
STORY: When it comes to flying, safety is paramount. But finding damage in aircraft isn't always easy - looking inside the materials in planes for signs of stress and structural integrity is challenging. But Anthony Croxford and his colleagues at Bristol University think they've found a way to find small damage in materials. And he says it could have far-reaching effects. SOUNDBITE: Bristol University Senior Lecturer in Mechanical Engineering, Anthony Croxford, saying (English): "You're essentially making an acoustic lens to give you much better resolution an a given place. The result of that means we can use a phased array to image what's going on inside a piece of metal and give us a very high resolution image of all points within that piece of metal by focusing all that energy at one location." Croxford and his team use something called nonlinear ultrasonics to look inside materials like metal. The arrays being used here send hundreds of sound signals through materials, and then listen to where they come back and what they sound like. This then gives a picture of what's inside the metal - and where even tiny pieces of damage and cracks could be. SOUNDBITE: Bristol University Senior Lecturer in Mechanical Engineering, Anthony Croxford, saying (English): "The way this works is that your energy essentially shakes that crack, it rattles it on the way in, and that leads to harmonics, so you put in one frequency, and you get out other frequencies. In a purely linear system, you only get out the frequency you put in. By using this novel approach we can now pick up a crack close to a hole, which is directly relevant, to say, aerospace applications, where they're worried about cracks growing from rivet holes, things like that." Croxford says the real strength of this new approach is in the tools required. The nonlinear method of acoustic imaging needs equipment already being used in industry. This could potentially mean a future where damaged materials are never in the sky.