Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282443
Title: Advanced non-contacting ultrasonic techniques for non-destructive testing
Author: Billson, Duncan Robert
ISNI:       0000 0001 2415 3691
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1994
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Abstract:
This thesis describes research towards the development of ultrasonic methods to test samples that are difficult to test using conventional techniques, with particular emphasis being given to non-contacting methods. The samples investigated in detail were adhesively bonded structures and zircalloy (a zirconium-niobium alloy). The adhesively bonded structures were investigated ultrasonically using an ultrasonic resonance technique (referred to as ultrasonic spectroscopy) to analyse suitable ultrasonic waveforms. This thesis starts by explaining a new approach to ultrasonic spectroscopy, and then describes a number of transduction techniques (both contacting and non-contacting) that were devised to obtain waveforms suitable for spectroscopic analysis. These including conventional piezoelectric transducers, laser generation of ultrasound, EMAT reception of ultrasound, and a novel couplant-free transducer. Tests were undertaken on a variety of samples under a number of different conditions, with the experimental results comparing well with those predicted by theory. Zircalloy was investigated next in an effort to evaluate non-destructively the concentration of hydride in the alloy. This was performed using velocity-temperature measurements (at temperatures up to 500°C) for both shear and longitudinal waves, and by dilatometry (thermal expansion) measurements. Both sets of tests successfully determined the hydride concentrations of test samples. A separate chapter is devoted to the description of some of the novel transducers developed during the course of this research, including a couplant-free transducer, and several transducers for airborne ultrasound. These transducers were found to operate well, the couplant-free transducer being particularly successful (subsequently finding a number of industrial applications). The final experimental chapter describes the building of both a photoelastic, and a schlieren rig that were used to visualise ultrasound, with the intention of giving an insight into some of the ultrasonic phenomena that were associated with the rest of the work. The results obtained were invaluable in analysing the results from previous chapters.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.282443  DOI: Not available
Keywords: QC Physics ; QD Chemistry ; TA Engineering (General). Civil engineering (General)
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