Author: | Huang, Yuhan |
Title: | Interfacial stresses and debonding in corroded steel plates locally repaired with a thin bonded plate |
Degree: | M.Sc. |
Year: | 2012 |
Subject: | Steel, Structural. Hong Kong Polytechnic University -- Dissertations |
Department: | Department of Civil and Structural Engineering |
Pages: | ix, 87 leaves : col. ill. ; 30 cm. |
Language: | English |
Abstract: | Structural strengthening is an important research field of civil engineering, and external bending of fiber reinforced polymer is a recent structural strengthening method. External FRP strengthening of metal structures has many outstanding advantages, such absence of serious stress concentration or residual stresses, convenient construction, and low maintenance costs. There are many issues to be studied in FRP strengthened metal structures. In this study, a systematic numerical investigation together with an experimental program was carried out on the strengthening and repairs of steel plates with a hole by bonding an FRP laminate. Finite element simulations were used in the numerical study. Both axis-symmetric models and three dimensional models were applied in modelling a thick circular steel plate with a central hole bonded with a thin FRP plate under an uniform pressure acting on the FRP plate through the hole. The mesh convergence study and the parametric study were first conducted for a bonded plate of an isotropic material using an axis-symmetric finite element modell. Both isotropic and orthotropic bonded materials were then considered using a three-dimensional finite element modell. Comparisons between results from the axis-symmetric model and three-dimensional model were made. Meanwhile, variation of predicted interfacial stresses with the number of layers of bonded material were examined made. Experiments were conducted on thick steel circular steel plates with a central hole bonded with a thin aluminum plate and steel plate. Four groups of tests were conducted. Each group had a different bonded plate material and thickness. The force-deformation diagrams are presented. Also the failure mode is discussed. Several conclusions were drawn from the research and analysis as following, the interfacial stresses near hole edge in two-dimensional analysis can be concluded in four points. The thinner adhesive layer, stiffer adhesive layer, thinner soffit plate, and more flexible soffit plate material all lead larger interfacial stresses. In three-dimensional analysis, the normal stress of orthotropic material is larger than the same thickness isotropic material for multi-layers of FRP liner. The shear stress is a more complicated. In the experiment, steel plate has a hole bonded with aluminum plate is not good as steel bonded plate. However the property of the pressure resistance is proportion to the thickness. And the maximum deformation has inverse proportion to the thickness. Base on the conclusions and recommendations, the work presented in this thesis provides useful information for the FRP strengthening of corroded metal pipes. |
Rights: | All rights reserved |
Access: | restricted access |
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File | Description | Size | Format | |
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b2554567x.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 6.61 MB | Adobe PDF | View/Open |
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