"This study aims to develop and validate a compact, integrated lab-on-sensor system for simultaneous measurement of strain, temperature and corrosion-induced mass loss in steel structures and concrete reinforcement elements in order to assess their life-cycle performance. The sensing system operates based on the principle of long period fiber gratings (LPFG) that are responsive to both thermal and mechanical deformation, and the change in refractive index of any medium surrounding the optical fiber. To fabricate a LPFG sensor for strain and temperature measurement, a CO2 laser aided fiber grating system was assembled. To enable mass loss measurement, a low pressure chemical vapor deposition (LPCVD) system was built to synthesize a graphene/silver nanowire composite film as flexible transparent electrode for the electroplating of a thin Fe-C layer on the curve surface of a LPFG sensor. Together with two LPFG sensors in LP06 and LP07 modes for simultaneous strain and temperature measurement, three Fe-C coated LPFG sensors were multiplexed and deployed inside three miniature, coaxial steel tubes to measure critical mass losses through the penetration of tube walls and their corresponding corrosion rates in the life cycle of an instrumented steel component. A Fe-C coated LPFG sensor was submerged in a NaCl solution and calibrated for stress corrosion cracking under three strain levels. The corrosion mechanism of the Fe-C layer was investigated and the distribution of cracks (width, length and spacing) were characterized and correlated with the wavelength change of the sensor. Thermal, loading and accelerated corrosion tests were conducted to validate the functionality, sensitivity, accuracy, and robustness of the proposed sensing system and demonstrate its feasibility in in situ applications"--Abstract, page iii.
Yan, Guirong Grace
Civil, Architectural and Environmental Engineering
Ph. D. in Civil Engineering
Missouri University of Science and Technology
xiv, 126 pages
© 2019 Chuanrui Guo, All rights reserved.
Dissertation - Open Access
Electronic OCLC #
Guo, Chuanrui, "Long period fiber grating, thin coating of graphene and silver nanowires, and corrosion sensing for life-cycle assessment of steel structures" (2019). Doctoral Dissertations. 2886.