"In order to ensure the continued safe and reliable operation of various civil structures, such as dams, bridges, and buildings, in situ strain monitoring is of great importance, especially for structures that may experience large strains. A new coaxial cable Bragg grating (CCBG) is developed as a strain sensor and the sensor's capacity for large range strain measurement is demonstrated for the first time. The sensor device is comprised of regularly spaced periodic discontinuities along a coaxial cable. The discontinuities are fabricated using a computer numerical controlled (CNC) machine to drill holes in the cable. Each discontinuity generates a weak reflection to the electromagnetic wave propagating inside the cable. Superposition of these weak reflections produces a strong reflection at discrete frequencies that can be explained by Bragg grating theory. A positive feedback oscillation system is also developed to enhance the measurement accuracy. The Q-factor was enhanced by 3500 times in this case. By monitoring the resonant frequency shift of the sensor's reflection or transmission spectra using the oscillation system, strain measurement sensitivity of 20με and a dynamic range of 50000με (5%) were demonstrated for axial strain measurements. The temperature responses of various types of CCBGs have also been investigated. The experimental results show that the CCBG sensors perform well for large strain measurement needed in structural health monitoring (SHM)"--Abstract, page iii.
Xiao, Hai, Dr.
Fan, Jun, 1971-
Electrical and Computer Engineering
M.S. in Electrical Engineering
National Science Foundation (U.S.)
Missouri University of Science and Technology
viii, 37 pages
© 2012 Jie Huang, All rights reserved.
Thesis - Open Access
Library of Congress Subject Headings
Coaxial cables -- Testing
Electronic circuits -- Noise
Print OCLC #
Electronic OCLC #
Link to Catalog Recordhttp://laurel.lso.missouri.edu/record=b10721804~S5
Huang, Jie, "Coaxial cable Bragg grating" (2012). Masters Theses. 7357.