There is increasing interest in permanently installed sensors to monitor the integrity of a structure. One relatively simply idea is to deploy ultrasonic thickness gauges, but these have the disadvantage that they only measure at a single point so the reading obtained is dependent on the monitoring point(s) chosen. An attractive alternative would be to deploy a ring of sensors to map the thickness of the region in the ring. This can be achieved by using transducers that excite guided waves in the structure and processing the received data by diffraction or velocity tomography. This project is investigating the pros and cons of the two approaches and the resolution obtainable as a function of the area within the ring, the number of transducers and the frequency and mode used. You can view a presentation here.

Graph showing a Guided Wave Tomography for Thickness Mapping


Belanger, P. and Cawley, P. 'Feasibility of low frequency straight-ray guided wave tomography', NDT&E International, Vol 42, pp113-119, 2009.

Belanger, P., Cawley, P. and Simonetti, F. 'Guided wave diffraction tomography within the Born approximation', IEEE Trans UFFC, Vol 57, pp1405-1418, 2010.

Huthwaite, P., Simonetti, F., ‘High-resolution imaging without iteration: a fast and robust method for breast ultrasound tomography’. The Journal of the Acoustical Society of America. 130(3): p. 1721.


EPSRC, Shell, Petrobras