[4B1] Improving industrial inspections combining high-frequency flexible ultrasonic arrays and coded excitation
E Germano¹, M Tabatabaeipour¹, E Mohseni¹, A Gachagan¹, K Lam¹ and D Hughes²
¹University of Strathclyde, UK
²Novosound Ltd, UK
In this study, a commercial 20 MHz 64-element 1 mm-pitch flexible linear array, developed by Novosound Ltd, was evaluated using two different coded excitation techniques to enhance the signal-to-noise ratio and operability on flat and complex-geometry components. Chirp and Golay-coded excitation techniques were employed with an arbitrary waveform generation tool to excite the array. A pulse compression technique consisting of a matched filter was implemented, weighted by a Chebyshev window for Chirp excitation.
Preliminary results were acquired with the array deployed on a 20 mm-thick flat aluminium test specimen with side-drilled holes. An improvement of >17 dB for the backwall refection compared to a conventional pulse excitation was observed. The array offers flexibility to conform to complex-geometry surface profiles. A curved sample, representative of piping found in the nuclear industry, was investigated next using both direct coupling and through an attenuating rubber material that is suitable to scan the array over rough surfaces. For all experimental scenarios, both excitation schemes were optimised and compared in terms of capability for defect detection.
The proposed approach, incorporating the flexible array with coded excitation techniques, has the potential to improve industrial inspection quality in terms of efficiency, accuracy and reliability.
Keywords: high-frequency array, flexible array, complex-geometry components, ultrasonic NDE, coded excitation.
Preliminary results were acquired with the array deployed on a 20 mm-thick flat aluminium test specimen with side-drilled holes. An improvement of >17 dB for the backwall refection compared to a conventional pulse excitation was observed. The array offers flexibility to conform to complex-geometry surface profiles. A curved sample, representative of piping found in the nuclear industry, was investigated next using both direct coupling and through an attenuating rubber material that is suitable to scan the array over rough surfaces. For all experimental scenarios, both excitation schemes were optimised and compared in terms of capability for defect detection.
The proposed approach, incorporating the flexible array with coded excitation techniques, has the potential to improve industrial inspection quality in terms of efficiency, accuracy and reliability.
Keywords: high-frequency array, flexible array, complex-geometry components, ultrasonic NDE, coded excitation.
