Use this URL to cite or link to this record in EThOS:
Title: FPGA based digital electromagnetic sensing technique for detection of pit corrosion
Author: Rodriguez Gutierrez, Sergio
ISNI:       0000 0004 6499 0787
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2017
Availability of Full Text:
Access from EThOS:
Access from Institution:
This thesis describes the development of an eddy current instrument and its application in detecting early-stage pitting corrosion. Eddy current testing has previously been used in Non-Destructive Testing (NDT) applications detecting large defects, like cracks. However, the challenge of detecting corrosion pits of less than 1mm³ remains unaddressed. This research involved the design of a Field Programmable Gate Array (FPGA)-based eddy current instrument, and the design and modelling of a novel differential electromagnetic sensor. The FPGA provided accurate synchronisation among the major electronic components. The firmware developed as part of this research allowed for exact interfacing to A/D and D/A converters, performed a real-time demodulation and signal generation, the instrument also supported a multi-frequency eddy current application. The firmware showed promising end-results in terms of sensitivity and stability in relation to pitting corrosion detection. In summary, this instrument offered significant improvement in sensitivity; the size of corrosion detected is improved more than 10 per cent compared to the previously reported, which enabled the detection of pits smaller than 1 mm³. For the sensor probe, a novel differential sensor was proposed to minimise the background signal for plate scanning and improve the sensitivity. The designed probe has an advantageous feature: the sensor response can be analysed using a closed form analytical solution.
Supervisor: Yin, Wuliang Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: FPGA ; Eddy Current