Defect amplitude response approximation using TCG calibrated CIVA simulation of PAUT inspection
M McInnes1, R O’Leary1, A Gachagan1 and A Glover2
1Centre for Ultrasonic Engineering (CUE), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow G1 1XQ, UK
Email: matthew.j.mcinnes@strath.ac.uk
2QinetiQ, Rosyth, UK
Modelling packages, such as CIVA, can be used to replicate the interaction of ultrasonic inspection systems with weld joint geometry and welding flaws. The sizing and sentencing of all defects within a welded joint is of the utmost importance in order to decide whether the component needs repairing or replacing or can be left to be regularly monitored. Comparison of experimental data with CIVA simulated data shows that defect structures, such as cracks and lack of fusion defects, can be replicated effectively. And when sized based on the dB drop method, very similar magnitudes of defect length are also achieved. However, there are significant differences in amplitude response between the simulated and experimental data, resulting in the simulated data being sentenced differently to the experimental data. To make an effective comparison, the same calibration method used within the experimental set-up has to be imitated within simulation. Time -corrected gain (TCG) is a calibration technique that operates by producing the same amplitude response for the same defect at varying depths. Due to CIVA’s current inability to replicate the TCG calibration process, simulated outputs cannot be appropriately compared with experimental data. However, CIVA simulations can be run to replicate the calibration process to extract the necessary data to provide the reference amplitudes to appropriately scale the simulated inspection. By investigating to improve the approximated defect amplitude response, it will allow for better structure geometry approximation for unknown defects and ensure more appropriate sentencing for simulation data. By doing so, it will reduce the need for test sample construction and therefore reduce the cost, time and effort required to construct and inspect such samples.
Keywords: time-corrected gain, CIVA, linear scanning phased array, ultrasound.
Keywords: time-corrected gain, CIVA, linear scanning phased array, ultrasound.
