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Strengthening of Metallic Structures using Externally Bonded Fibre Reinforced Polymers Composite.Lam, Dennis January 2007 (has links)
No / Today¿s engineers spend an
increasing proportion of their
time on the maintenance and
retrofitting of existing structures.
Many of these structures were
designed for a purpose totally different
from that for which they are now
employed. The use of buildings has
changed over the last few decades
especially during the commercial boom
in the 1990s and bridge structures are
taking on more and more loads as
traffic on the roads continues to rise
dramatically.
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Load-displacement behavior of frame structures composed of fiber reinforced polymeric composite materialsNa, Gwang-Seok 17 November 2008 (has links)
This thesis addresses the results of an experimental and analytical investigation aimed at examining the static load-displacement response of braced plane frame structures composed of fiber reinforced polymeric (FRP) composite material structural members manufactured by the pultrusion process.
In the experimental part of this investigation, eighteen full-scale lateral loading tests for FRP composite frames with different brace configurations and beam column connection types were performed. The load-displacement responses of such frames were measured and are reported herein.
In the analytical part of this investigation, a frame analysis method that accounts for the anisotropic nature of FRP composite material structural members was investigated. The results from the experimental work are compared with the results from the analytical procedures. The effects of various structural parameters of the frame such as (1) effective mechanical material properties of members, (2) beam-column connection types, and (3) the influence of diagonal structural members on the lateral load-displacement response of the braced plane frames are also investigated.
The numerical load-displacement results from the proposed FRP composite frames analysis procedure provided good agreement with the results from the full-scale laboratory tests.
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Modélisation tribo-physique de la coupe des composites FRP : Approches numérique et expérimentale / Tribo-physical modeling of FRP composites cutting : Numerical and experimental approachesBen soussia, Aymen 27 June 2014 (has links)
Depuis des décennies, le processus d'enlèvement de matière des composites à matrices polymères (CMP) ne cesse de susciter des interrogations. La complexité et la multitude des phénomènes physiques activés par la coupe constituent encore un défi d'actualité pour la compréhension et la maitrise du comportement des structures composites. Ce travail propose une analyse multiéchelle fine des phénomènes élémentaires émanant du comportement de chacune des phases constituantes du matériau afin de modéliser leurs couplages multiphysiques potentiels conduisant à la formation du copeau. L'étude est alors hybride conjuguant l'approche expérimentale exprimée par l'essai instrumenté et l'approche numérique exprimée par la modélisation par éléments finis (EF). La formulation du couplage multiphysique a fait l'objet d'une routine VUMAT alliant la mécanique de l'endommagement continu à la mécanique de la rupture par le biais du triptyque élasticité-endommagement-rupture. A la différence des approches binaires de la littérature, le modèle développé dans ce travail s'appuie sur un concept d'endommagement progressif pour prédire la rupture physique des phases, et par conséquent, la formation du copeau. Les mécanismes d'initiation et de propagation de la fissure sont pilotés par les énergies de rupture des phases identifiées selon les normes en vigueur. La gestion du contact par une routine VFRIC a permis d'assurer la synergie entre les propriétés locales de l'interface et les frottements générés. Les calculs ont démontré la pertinence du modèle tridimensionnel proposé dans la simulation des mécanismes de formation du copeau sensiblement à l'orientation et la nature des fibres. La bonne concordance entre les mesures et les prédictions d'efforts de coupe a mis en évidence l'intérêt d'un pilotage rigoureux du contact outil-pièce pour la simulation multiphysique de la coupe. / Since several decades, the material removal process of Fiber Reinforced Polymers (FRP) continues to raise technical and scientific queries. The understanding of the multiple and complex phenomena generated when cutting still remains challenging for controlling the behavior of composite structures. This study addresses a multiscale analysis of elementary phenomena associated to each of the composite constituents in order to model the chip formation mechanisms owing to the multiphysical coupling. An investigation combining the experimental approach resulting in the instrumented test and numerical approach allowing to the finite element (FE) development was hence conducted. A VUMAT subroutine was built to express the constitutive formulation coupling the continuum damage mechanics to the failure mechanics by means of the triptych elasticity-damage-failure. Unlike to the binary approaches proposed by the open literature, the model proposed herein bases on the progressive damage concept for predicting the physical failure allowing to the formation of the chip. The crack initiation and growth mechanisms are controlled by the failure energies determined experimentally for each material phase. The efficiency of the VFRIC subroutine to managing the contact properties, i.e. friction, at the tool-material interface was confirmed. The numerical results proved the reliability of the model to simulate the chip formation mechanisms with respect of fiber orientation. The good agreement between the measured and predicted forces proved the interest of the rigorous modeling of the tool-material interface.
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Sledování trvanlivosti FRP kompozitních materiálů (kompozitů s dlouhovláknovou výztuží a polymerní matricí) / Monitoring the durability of FRP composite materialsJanák, Petr January 2015 (has links)
This diploma thesis deals with evaluation of the conditions for laboratory testing of composite profiles with fiber-reinforced polymer (FRP). Theoretical part describes the main material properties of FRP profiles and method of manufacturing by pultrusion. Experimental part evaluates imposition of the test samples in alkaline environment and their subsequent changes in physical properties. Next part contains evaluation of cuts FRP profiles by electron microscopy in combination with element analysis. The outcome of this work is the method of evaluation of accelerated durability FRP profiles.
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Progresivní styčníky FRP kompozitů konstrukcí dopravní infrastruktury / Joints from FRP composite intended for transport infrastructureSimon, Pavel January 2018 (has links)
This thesis deals with junction points of construction used in transport infrastructure, which are made of FRP composite material. Main focus is on bonded joints. The material and geometrical criteria od FRP material and there influence to junctions are analyzed. In sequential steps the development of the design of joints applicable to reference constructions - pedestrian walkways is documented. There are also presented practical experiences from the tests of joints of overlapped and single-sided joints, as well as experience from the design, production and testing of two types of pedestrian bridges on a real scale. Furthermore, extensive comparison of joints, in particular T-joints with closed profiles for selected types of fasteners, is provided. From a simple connection, screws and rivets or plain bonding to combined joints. These are assessed both in terms of bearing capacity and their deformation behavior. These tests are performed for two material combinations, FRP-FRP and FRP-steel.
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Studium vlastností FRP kompozitních materiálů pro vyztužování betonu / Study of FRP for concrete reinforcementBlahová, Aneta January 2022 (has links)
The diploma thesis aims to analyze bent FRP reinforcements. It describes the method of production of bent FRP reinforcement, examples of application of FRR reinforcement in structures and mentions aggressive influences influencing the durability of FRP reinforcement. Furthermore, an experiment is proposed to monitor changes in straight and bent FRP reinforcement stored in an aqueous environment at 20 °C and an alkaline environment at 20 °C and 40 °C. The output of the diploma thesis is the evaluation of changes in mechanical properties and durability. The condition of the FRP reinforcement is documented using optical and electron mocroscopy.
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Řešení vybraných detailů betonových konstrukcí vyztužených kompozitní výztuží / Design of selected details of concrete structures reinforced with composite reinforcementVašátko, David January 2022 (has links)
The aim of this master thesis is to explore and describe behavior of slab in punching shear. In total four concrete slabs were experimentally tested; each being reinforced differently. Using real experiments, there was a possibility to observe different behavior of steel and FRP reinforcement, eventually even the effect of adding FRP stirrups on load-bearing capacity. For the purpose of experimental testing design, currently placed formulas used to determine punching shear capacity were adjusted for application on longitudinal and shear FRP reinforcement. Atena software was used to approximate behavior of specimens by performing a nonlinear analysis. After the results of loading tests were obtained, next step was the comparison of design approaches and comparison of behavior of nonlinear model to a real specimen. In practical part, design of locally supported slab with requirement of non-magnetic reinforcement took place.
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STABILITY OF BURIED STEEL AND GLASS FIBRE REINFORCED POLYMER PIPES UNDER LATERAL GROUND MOVEMENTAlmahakeri, MOHAMED 19 April 2013 (has links)
As vast networks of high pressure buried energy pipelines traverse North America and other continents, the stability of such essential buried infrastructure must be maintained under a variety of earth loading conditions. The pipe-soil interaction and the longitudinal behaviour of buried pipes due to relative ground movements is poorly understood. This thesis presents full scale testing and numerical modeling of steel and Glass Fibre Reinforced Polymer (GFRP) pipelines to better understand the flexural performance of buried pipes subjected to lateral earth movement.
For the experimental phase of the study, a series of pipe bending experiments have been conducted on 102 mm nominal diameter and 1830 mm long steel and GFRP pipes buried in dense sand. Pipe loading was carried out by pulling pipe ends using two parallel cables attached to a spreader beam outside the test region, using a hydraulic actuator. The different tests covered burial depth-to-diameter (H/D) ratios of 3, 5 and 7. During the steel pipe testing phase, special consideration was given to assess the effect of boundary limits, friction within the pulling mechanism, and consistency of results using repeated tests. For the GFRP pipes, the experimental work investigated the effect of the laminate structure of the pipes, including both cross-ply and angle-ply laminates. Test results showed that burial depth significantly influenced the ultimate pulling forces, longitudinal strains, and pipe net deflection at mid-span. The results were also compared between the two types of pipes. The failure mechanism for all tests was consistently governed by soil failure, except for the angle-ply GFRP pipe that failed at a burial depth of H/D=7.
For the numerical analysis, the study presents the development and verification of two and three-dimensional numerical models including material constitutive models for both the pipe and for the soil using a stress-dependent modulus. Calculations are presented for different burial depths and are compared to experimental data. It was shown that the numerical model can successfully capture the pipe-soil interaction behaviour for both pipe types in terms of load-displacement responses and net bending deflection. Also, the effect of material variation and laminate structure were in agreement with test data. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2013-04-18 22:21:53.025
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Experimental analysis of the efficiency of carbon fiber anchors applied over CFRP to firebrick bonded joints / Analyse expérimentale de l’efficacité des systèmes d’ancrage en fibre de carbone appliqués sur briques renforcées par CFRPCaggegi, Carmelo 21 March 2013 (has links)
Dans les dernières années, le renforcement des bâtiments en maçonnerie a connu une usure massive des bandes CFRP. Ces matériaux composites, attachés sur les éléments à renforcer, sont exposés à une fracture prématurée pour délaminage (...). Une façon pour accroître la résistance maximale du système renforcé par CFRP est d'améliorer la cohésion entre support et composite en utilisant des ancrages mécaniques. Ces derniers sont réalisés en utilisant les mêmes typologies de fibres de renforcement et en les insérant dans le support comme des «clous». Les recherches scientifiques sur l'usure de cette façon d'ancrage sur support en maçonnerie ont été très limitées et, dans ce contexte, il n'y a pas d'études expérimentales sur le projet et le placement des ancrages. L'objectif principal du présent travail de thèse est de quantifier l'efficacité des ancrages en fibre de carbone appliqués sur brique (...) par les bandes CFRP. Cette recherche est la première phase d'une étude plus vaste sur les systèmes de maçonnerie-CFRP renforcés par « carbon fiber anchor ». Dans l'étude, l'analyse des déplacements et des déformations de la surface renforcée a été faite en utilisant la Corrélation des Images (DIC), une avantageuse méthode optique jamais utilisée pour l'étude des systèmes «support-CFRP band- ancrages».Le présent travail de thèse démontre que les ancrages en CFRP augmentent le résistance maximale et la ductilité des renforcements par bande de composites. Donc, cette typologie d'ancrage augmente la sécurité des personnes pendant les tremblements de terre et ne permettent pas la fracture fragile de la structure renforcée. La corrélation des images a été un bon outil pour l'étude des déformations, des avantages et des inconvénients de cette méthode et ont été évalué pendant la recherche / In these recent years, the strengthening of masonry building has known a massive use of CFRP sheets. Those composite materials glued on the elements to reinforce are exposed to prematurely debonding crisis due to a tension load which is much smaller than the tensile strength of the CFRP. A way to upgrade failure load of CFRP-to-support bonded joint is to reinforce the cohesion between the fibers and the support by the use of mechanicals anchors built with the same fibers of the composite and fastened in the support like “nails”. Research on the use of anchors for masonry supports has been limited and, in this framework, there are no experimental analyses related to the design and the placement of fiber anchors. The aim of this thesis is to provide experimental data to quantify the efficiency of the carbon fiber anchors applied on a reinforced fire brick. This is a ground work to study CFRP to masonry bonded joint fastened by fiber “nails”. Specifically, the analysis of the displacement and the strain fields of the reinforced surface have been realized by means of Digital Image Correlation (DIC), an optical appealing method never used to study a FRP to support bonded joint fastened by FRP anchor. The research demonstrates that the use of the CFRP anchor increases the resistance and the ductility of the reinforcements. The latter are important to augment the mechanical features of the structural members and, especially, to increase the safety of people during earthquakes by avoiding the brittle collapse of the strengthened elements. The digital image correlation has been a good tool for the strain field analysis; strengths and weaknesses of this method have been evaluated
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Análise teórica de vigas pré-moldadas de concreto com armadura de aço e de polímero reforçado com fibra de vidro em meio altamente agressivo / Theoretical analysis of precast concrete beams with steel bars and polymer reinforced with glass fiber in aggressive environmental sitesMicali, Roberto Mauricio 29 April 2010 (has links)
Este trabalho analisou o comportamento estrutural de polímeros reforçados com fibra de vidro - PRFV em elementos pré-moldados de concreto, com aplicações específicas em vigas de concreto. Realizou-se um estudo comparativo do comportamento de vigas pré-moldadas reforçadas com armadura convencional, segundo a norma brasileira NBR 6118:2003, e reforçadas com armadura de barras pultrudadas de PRFV, segundo o ACI 440.1R-06. O estudo visa obter subsídios para a aplicação de barras de reforço de PRFV, em relação ao Estado Limite de Serviço - ELS, em obras realizadas em regiões de alta agressividade ambiental. Posteriormente fez-se os mesmos modelos de cálculo em elementos finitos, onde foram comparados e analisados os resultados obtidos com o cálculo prescrito pelas normas. Nem todos os parâmetros da norma americana foram inseridos, uma vez que alguns coeficientes internos que contam com efeitos sísmicos e com a neve estão embutidos nos cálculos. Os resultados obtidos, principalmente no cisalhamento, foram altamente satisfatórios, validando a aplicação do PRFV nas vigas consideradas. / This work studied the behavior of precast beams when subjected to shear stress according to the brazilian standard NBR 6118:2003 reinforced with steel bar compared to the american standard ACI 440.1R-06 when the structural member was reinforced with glass fiber reinforced polymer - GFRP pultruded bars. The goal of this work is to acquire subsidies to apply the GFRP in aggressive environmental sites. Also the same model calculations were performed by using Finite Element Method and compared to the results of the calculation prescribed by the standards. Some parameters indicated in the ACI standard were not followed since they are related to seismic and snow effects. The obtained results mainly in shear loading were highly satisfactory which validates the use of GFRP in the considered beams.
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