Picture of person typing on laptop with programming code visible on the laptop screen

World class computing and information science research at Strathclyde...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of Open Access research papers by University of Strathclyde researchers, including by researchers from the Department of Computer & Information Sciences involved in mathematically structured programming, similarity and metric search, computer security, software systems, combinatronics and digital health.

The Department also includes the iSchool Research Group, which performs leading research into socio-technical phenomena and topics such as information retrieval and information seeking behaviour.


A Maximum Eigenvalue Approximation for Crack-Sizing Using Ultrasonic Arrays

Cunningham, Laura and Mulholland, Anthony J. and Tant, Katherine M. M. and Gachagan, Anthony and Harvey, Gerry and Bird, Colin (2015) A Maximum Eigenvalue Approximation for Crack-Sizing Using Ultrasonic Arrays. Working paper. University of Strathclyde, Glasgow. (Unpublished)

Text (Cunningham-etal-A-maximum-Eigenvalue-approximation-for-crack-sizing-using)
Cunningham_etal_A_maximum_Eigenvalue_approximation_for_crack_sizing_using.pdf - Preprint

Download (391kB) | Preview


Ultrasonic phased array systems are becoming increasingly popular as tools for the inspection of safety-critical structures with in the non-destructive testing industry. The datasets captured by these arrays can be used to image the internal microstructure of individual components, all owing the location and nature of any defects to be deduced. Unfortunately, many of the current imaging algorithms require an arbitrary threshold at which the defect measurements can be taken and this aspect of subjectivity can lead to varying characterisations of a flaw between different operators. This paper puts forward an objective approach based on the Kirchoff scattering model and the approximation of the resulting scattering matrices by Toeplitz matrices. A mathematical expression relating the crack size to the maximum eigenvalue of the associated scattering matrix is thus derived. The formula is analysed numerically to assess its sensitivity to the system parameters and it is shown that the method is most effective for sizing defects that are commensurate with the wavelength of the ultrasonic wave (or just smaller than. The method is applied to simulated FMC data arising from finite element calculations where the crack length to wavelength ratios range between 0.6 and 1.8. The recovered objective crack size exhibits an error of 12%.