Author, Institution: Gawher Ahmad Bhat, Kaunas University of Technology
Science area, field of science: Technological Sciences, Electrical and Electronic Engineering, T001
Research supervisor: Prof. Dr. Elena Jasiūnienė (Kaunas University of Technology, Electrical and Electronic Engineering, T001)
Dissertation Defence Board of Electrical and Electronic Engineering Science Field:
Prof. Dr. Dangirutis Navikas (Kaunas University of Technology, Technological Sciences, Electrical and Electronic Engineering, T001) – chairperson
Prof. Dr. Richard Degenhardt (University of Bremen, Germany, Technological Sciences, Measurement Engineering, T010)
Prof. Dr. Mikko Samuli Kanerva (Tampere University, Finland, Technological Sciences, Materials Engineering, T008)
Prof. Dr. Vaidotas Marozas (Kaunas University of Technology, Technological Sciences, Electrical and Electronic Engineering, T001)
Chief Researcher Dr. Vykintas Samaitis (Kaunas University of Technology, Technological Sciences, Electrical and Electronic Engineering, T001)
Dissertation defence meeting will be at Rectorate Hall of Kaunas University of Technology (K. Donelaičio 73-402, Kaunas)
The doctoral dissertation is available at the library of Kaunas University of Technology (Gedimino 50, Kaunas) and on the internet:G. A. Bhat el. dissertation.pdf
© G. A. Bhat, 2026 “The text of the thesis may not be copied, distributed, published, made public, including by making it publicly available on computer networks (Internet), reproduced in any form or by any means, including, but not limited to, electronic, mechanical or other means. Pursuant to Article 25(1) of the Law on Copyright and Related Rights of the Republic of Lithuania, a person with a disability who has difficulties in reading a document of a thesis published on the Internet, and insofar as this is justified by a particular disability, shall request that the document be made available in an alternative form by e-mail to doktorantura@ktu.lt.”
Annotation: The growing demand for lightweight and fuel-efficient aircraft structures has prioritized the usage of adhesively bonded joints as an alternative to conventional joining techniques such as mechanical fastening and welding. Adhesive bonding offers several advantages, including uniform stress distribution, reduced structural weight, improved stiffness, and high impact resistance. However, the lack of a reliable nondestructive evaluation (NDE) technique capable of accurately assessing bond integrity and detecting interfacial defects remains a major limitation to their wider industrial adoption, particularly in safety-critical sectors such as aerospace and automotive engineering. This study investigates defect characterization in adhesively bonded joints using ultrasonic and radiographic testing, supported by numerical simulations. Two representative defect types, namely inclusions and delaminations, were analyzed to examine their influence on ultrasonic wave propagation and radiographic image contrast. A range of signal-based and image-based features were extracted from both inspection modalities in order to identify parameters most sensitive to flaw presence, size, and geometry. To improve defect detection reliability, data fusion methodologies integrating ultrasonic and radiographic features were developed and implemented. The fusion-based results demonstrated improved defect detectability compared with single methods. The reliability of inspection performance was quantitatively assessed using Model-Assisted Probability of Detection (MAPOD) analysis. Furthermore, the use of custom developed feature extraction, rather than the conventionally used maximum amplitude, significantly improved defect detection capability, highlighting the importance of feature-driven analysis in non-destructive testing and evaluation.
22nd of May, 2026, 10:00
Rectorate Hall at Kaunas University of Technology (K. Donelaičio 73-402, Kaunas)
Add to iCal
