The Library
Magnetostrictive patches for guided wave inspection of composites
Tools
Zitoun, Akram (2022) Magnetostrictive patches for guided wave inspection of composites. PhD thesis, University of Warwick.
|
PDF
WRAP_THESIS_Zitoun_2022.pdf - Submitted Version - Requires a PDF viewer. Download (7Mb) | Preview |
Official URL: http://webcat.warwick.ac.uk/record=b3876604
Abstract
The work conducted within this PhD investigated the general characteristics of removable magnetostrictive thin patches for the generation of guided waves in plates that can be used for defect detection in composite structures. Initial experiments measured the directivity of SH, S0 and A0 guided waves modes in a metallic plate while varying the applied static and dynamic magnetic fields. Multiple coil geometries and permanent magnets were used to vary the field parameters, so that both Lorentz and magnetostrictive forces could be created. It was demonstrated through this initial testing that guided waves patterns could be controlled by careful control of these parameters.
Experiments were also conducted to investigate the vibrational characteristics of the magnetostrictive patch itself for variations in both the static and dynamic magnetic fields and the excitation frequency. It was demonstrated that the vibrations within the patch could be controlled and enhanced by varying the excitation frequency and by varying the direction and amplitude of the applied magnetic fields. Another finding was that for low frequencies, the natural frequency of the patch can contribute to the vibration enhancement. However, for higher frequencies of up to 250 kHz, it was shown that the magnetostriction is the main transduction mechanism generating vibrations within the patch.
Finally, the magnetostrictive patch was used to inspect a lab-induced defect in a CFRP sample and then a delamination within a GFRP plate. The optimised excitation parameters were then used to generate guided waves within these composite samples, and images of the defects produced using the synthetic aperture focusing technique (SAFT) for image reconstruction.
Item Type: | Thesis (PhD) | ||||
---|---|---|---|---|---|
Subjects: | Q Science > QC Physics T Technology > TA Engineering (General). Civil engineering (General) |
||||
Library of Congress Subject Headings (LCSH): | Magnetostriction, Composite materials, Ultrasonic waves, Lorentz force, Lamb waves, Electromagnetic fields, Nondestructive testing | ||||
Official Date: | March 2022 | ||||
Dates: |
|
||||
Institution: | University of Warwick | ||||
Theses Department: | School of Engineering | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Hutchins, David A. ; Dixon, Steve M. | ||||
Sponsors: | European Commission | ||||
Format of File: | |||||
Extent: | xvi, 183 pages : colour illustrations, charts | ||||
Language: | eng |
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |