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Russell Niven
PhD student, 2016 intake
University: University of Strathclyde
Sponsor: University of Strathclyde/NDEvR
Background: Undergraduate MSci Mathematics, University of Glasgow June 2015.
Ultrasonic phased arrays generate a rich data set – the Full Matrix Capture(FMC) – that contains knowledge about the material in which the ultrasonic waves has travelled through as well as any flaws it encountered. In heterogeneous materials the material microstructure has a significant effect on the recorded waveforms suggesting that it is possible to reconstruct the material map (the so called inverse problem). Some progress has made in this direction in timeofflight data from the FMC. However this discards a rich data set contained in the full waveform.
The aim of the project will be to develop a method to solve the inverse problem of recovering the material map in heterogeneous materials and, in so doing, improve the imaging of flaws. This will be done by:
– using Voronoi diagrams to mathematically parameterise the material geometry
– using a raybased forward model to chart the path of the wave through the material.
– devising a suitable metric to quantify the misfit between the modelled waveform and the experimental counterpart.
– developing Bayesian and deterministic protocols for solving the inverse problem.
– using synthetic FMC datasets from finite element simulations complemented a series of experimental investigations on industrially relevant test samples.