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Bond Monitoring in Externally Bonded Fiber Reinforced Polymer Composites in Civil Infrastructure
Başlık:
Bond Monitoring in Externally Bonded Fiber Reinforced Polymer Composites in Civil Infrastructure
Yazar:
Joshi, Kunal, author.
ISBN:
9780438009288
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (184 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Tarik J. Dickens Committee members: Zhiyong (Richard) Liang; Okenwa Okoli; John Sobanjo; Mei Zhang.
Özet:
External bonding of fiber-reinforced polymers (FRP) is currently one of the most popular techniques for rehabilitation of concrete structures. However, the effectiveness of the technology largely depends on the strength of the bond between the FRP laminate and the concrete substrate. This research investigates the potential for bond monitoring in externally bonded FRP laminates on concrete structures by identifying the loss of stiffness through triboluminescent (TL) optical fiber sensors. The optical fiber sensors are embedded within the bond region to provide distributed sensing. Two different orientation of sensors within the bond region were studied. The experimental analysis showed that the orientation of the sensor along the force direction (90°) did not result in any parasitic effect on the mechanical performance. However, the sensor oriented perpendicular (0°) to the direction of force reduced the bond strength by 42%, due to the characteristic stress distribution. The emission intensity was found to be 100% higher with 90° orientation due to the shear stress distribution. The average bond strength observed in experimental as well as numerical modeling was 3 MPa in a single lap shear test. In the tests conducted in this research, it was observed that along with the cohesive and adhesive failure, there exists a mixed-mode failure. The observed failures consisted of three critical phases which were well indicated by the TL sensor. The phase I failure typically occurs at the end of the bond region and was observed to initiate at a bond stress of 1.75 MPa. Phase II failure is the nucleation and propagation of the cracks within the interface or in the epoxy itself. The phase II failure was found to occur at a stress of 2.25 MPa. Phase III failure is said to occur when the two materials separate and was found to occur at a stress of 3 MPa. Triboluminescent signatures were observed at each of these structural state changes. The emissions are classified using a unique graphing technique. The graph is called a "scatter central plot" which enables identification of the damage state condition in the host material. In comparison to traditional FBG sensor, which possesses a pressure sensitivity of 70 MPa, the TL sensor proves to be superior. In addition, a damage localization scheme is provided to be able to establish higher levels of SHM. The bond region damage-monitoring technique presented in this research aims at providing a tool to reduce the response and decision-making time involved in the maintenance of deficient structures.
Notlar:
School code: 0872
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(678649.1) | 678649-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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