A new imaging technique could detect damage invisible to current acoustic imaging.

The next generation of aircraft may be even thinner and lighter thanks to the development by researchers from the University of Bristol's Ultrasonics and Non-destructive Testing (NDT).

Currently, engineers can take images of the interior of components using ultrasound, but they can only detect relatively large cracks and breaks.

But the British team says their ‘nonlinear acoustic technique’ could change this.

Imaging of acoustic nonlinearity is achieved by exploiting differences in the propagation of fields produced by the parallel and sequential transmission of elements in ultrasonic arrays.

“Imaging acoustic nonlinearity not only provides sensitivity to smaller defects than is currently possible but may have the potential to detect damage before macroscopic material changes occur,” Dr Jack Potter, Research Assistant in the Department of Mechanical Engineering and study leader, said.

“This would enable intervention before cracks have even begun to form, as well as predicting the remaining life of an engineering structure.

“Crucially the technique has been achieved using standard inspection equipment, which will allow for the rapid implementation of the technique in numerous applications.”

Such advances in non-destructive evaluation not only increase the safety of engineering structures but can help future design, for example, allowing the next generation of aircraft to be built thinner and lighter.

The paper, Nonlinear Ultrasonic Phased Array Imaging, is published here.