The energy dissipation capacity resulting from progressive cracking and the recovery after unloading of the web-flange junctions (WFJs) of a pultruded GFRP deck were experimentally investigated. Web-cantilever bending experiments up to failure were performed on two WFJ types (If-o, Ic-o) with similar geometry and fiber architecture but different initial imperfections (deviations from the fiber architecture design, wrinkling of fabrics, resin pockets, pre-cracks). Dissimilar imperfections changed the WFJ behavior from brittle (If-o) to ductile (Ic-o): different crack sequences were observed, which resulted in an abrupt failure in If-o WFJs and a progressive failure in Ic-o WFJs, in addition to a higher load-bearing capacity of the latter. The Ic-o WFJs exhibited significant recovery; a small influence of the FRP viscoelastic properties on recovery and a constant damage rate were observed. The total and dissipated energies of the Ic-o WFJs and their ductility index, defined as the ratio of the dissipated to total energy, were modeled. The main energy dissipation mechanism of the Ic-o WFJs was related to crack development; dissipation through viscoelastic losses was significant only at low deflection levels. (C) 2016 Elsevier Ltd. All rights reserved.
#1Sonia Yanes-Armas(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 4
#2Julia de Castro(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 15
Last. Thomas Keller(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 45
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The static transverse behavior of two pultruded GFRP deck systems with trapezoidal (DS) and triangular (AS) cell cross-sectional geometry was experimentally investigated in order to study their transverse in-plane shear stiffness. Symmetric three-point bending experiments up to failure were performed on 200-mm-wide beams. Their stiffness, strength and failure modes were compared. Different load transfer mechanisms were found in the DS (frame-dominated) and AS (truss-governed) systems depending o...
Last. Kevin D Potter(UoB: University of Bristol)H-Index: 37
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Abstract The aim of this research is to manufacture intermingled hybrid composites using aligned discontinuous fibres to achieve pseudo-ductility. Hybrid composites, made with different types of fibres that provide a balanced suite of modulus, strength and ductility, allow avoiding catastrophic failure that is a key limitation of composites. Two different material combinations of high strength carbon/E-glass and high modulus carbon/E-glass were selected. Several highly aligned and well dispersed...
Composite materials usage is limited by linear elasticity and the sudden, brittle failure they often exhibit. It is possible to mitigate this inherent limitation and enlarge the design space by using thin plies. This paper presents an experimental study, using a spread tow thin ply carbon–epoxy prepreg material with a cured ply thickness of 0.03 mm, which shows that highly non-linear stress–strain behaviour can be achieved with angle-ply laminates, whilst suppressing the damage mechanisms that n...
Last. Ignaas Verpoest(Katholieke Universiteit Leuven)H-Index: 32
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Abstract Fibre-reinforced composites are rapidly gaining market share in structural applications, but further growth is limited by their lack of toughness. Fibre hybridisation is a promising strategy to toughen composite materials. By combining two or more fibre types, these hybrid composites offer a better balance in mechanical properties than non-hybrid composites. Predicting their mechanical properties is challenging due to the synergistic effects between both fibres. This review aims to expl...
Abstract A new approach and material architecture is presented in order to overcome the inherent brittleness and unstable failure characteristic of conventional high performance composites. The concept is the use of thin-ply hybrid laminates. Fracture mechanics calculations were carried out to determine the critical carbon layer thickness for stable pull-out in a three layer unidirectional hybrid laminate, which can provide a pseudo-ductile failure. Unidirectional hybrid composites were fabricat...
The purpose of this paper is to provide a review of and observations on progressive failure and ductility of fiber-reinforced polymer (FRP) composites of interest to civil and infrastructure construction applications. The primary reason for this is that although FRP composites have over the last 25 years successfully penetrated niche markets in civil engineering applications, one of the most frequently heard concerns from designers is their discomfort with the ductility of these composites and t...
Abstract This paper focuses on the results and analysis performed on two types of hybrid FRP–UHPC beams, reinforced with either CFRP or SFRP tension sheets. The experimental program was conducted in two stages with a total of six beams tested. In Stage 1, six full length hybrid beams were tested until failure under four-point loading using both monotonic static and fatigue loading regimes. Then in Stage 2, the same beams were shortened to eliminate the sections of major damage and re-tested to d...
Last. Zhong Zhang(THU: Tsinghua University)H-Index: 1
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Abstract The creep and recovery of polypropylene/multi-walled carbon nanotube composites were studied. It was found for thermoplastics in general that the creep strain reduces with decreased temperature, and with enhanced content of carbon nanotubes. The incorporation of nanotubes improved the recovery property remarkably, especially at high temperature. The unrecovered creep strain of nanocomposites with content of 1 and 2.8 vol.% carbon nanotubes decreased by 53% and 73% compared to that of po...
Abstract The paper discusses the development of the advanced polymer composite material applications in the building and civil/structural infrastructure over the past three to four decades. It endeavours to identify and prioritise the important in-service research areas which are necessary to improve the understanding of the behaviour of FRP materials and FRP structural components. The paper demonstrates the types of structures which have been developed from the FRP composite material and the mo...
#1Thomas Keller(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 45
#2Martin Schollmayer(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 5
The through-thickness performance of adhesive joints between pultruded FRP bridge decks and steel girders was investigated experimentally and numerically. Through-thickness tensile stresses occur due to uplift forces caused by the load-bearing behavior of the bridge deck transverse to the bridge axis. The tensile stress distribution in the adhesive joint is non-uniform with high stress concentrations below the FRP webs of the cellular deck. The joint ultimate loads could be accurately predicted ...
#1Gisele G. Cintra(PUC-Rio: Pontifical Catholic University of Rio de Janeiro)H-Index: 1
#2Daniel C.T. Cardoso(PUC-Rio: Pontifical Catholic University of Rio de Janeiro)H-Index: 7
Last. Thomas Keller(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 45
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Abstract null null This paper aims to present an experimental investigation on the behavior of web-flange junctions (WFJs) rotational stiffness of pultruded fiber-reinforced polymer composites (FRP). Channels and I-sections were tested using a simple set-up, which was developed in order to experimentally characterize the junctions in a direct manner. The Digital Image Correlation (DIC) technique was used, allowing overall deflections and relative rotations between web and flange to be monitored....
Abstract null null This paper presents the experimental, analytical and numerical analyses on the behavior of the pultruded GFRP composite beams infilled with hybrid fiber reinforced concrete under four-point loading. The examined experimental variables included: (1) effect of pultruded GFRP box profile, (2) effect of conventional steel bars, GFRP bars and hybrid bars, (3) effect of externally GFRP wrapping. Pursuant to this goal, a total of 9 medium-sized beam specimens were constructed. The ex...
Abstract This paper presents a taxonomy of the fibre mat misalignments found in a multi-celled pultruded GFRP deck, based on high-resolution images of the polished cross sections. A dual approach to misalignment taxonomy is presented, one based on misalignment morphology, the other grounded in the manufacturing provenance of the misalignments. Each misalignment is characterised using, alternately, a Gaussian function, the angle to its steepest tangent, its length and its height. Some scatter in ...
Abstract An experimental investigation of the load-bearing behavior and ductility of FRP hybrid double-lap joints composed of both adhesively-bonded and bolted connection parts was conducted. Amongst other things, the effects of the adherends’ fiber architecture (uni- or multidirectional), adhesive type (stiff or flexible), and displacement rate were examined. The resistances of the hybrid joints with flexible adhesive corresponded to the full summation of the resistances of the bonded and bolte...
This paper investigated the static behaviour of glass fibre reinforced polymer (GFRP) built-up hollow and concrete filled built-up beams tested under four-point bending with a span-to-depth ratio of 1.67, therefore focusing their shear performance. Two parameters considered for hollow sections were longitudinal web stiffener and strengthening at the web–flange junction. The experimental results indicated that the GFRP hollow beams failed by web crushing at supports; therefore, the longitudinal w...
Out-of-plane fiber waviness, also referred to as wrinkling, is considered one of the most significant effects that occur in composite materials. It significantly affects mechanical properties, such as stiffness, strength and fatigue and; therefore, dramatically reduces the load-carrying capacity of the material. Fiber waviness is inherent to various manufacturing processes of fiber-reinforced composite parts. They cannot be completely avoided and thus have to be tolerated and considered as an in...
#1Ghazaleh Eslami(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 1
#2Sonia Yanes-Armas(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 4
Last. Thomas Keller(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 45
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Abstract Fiber-reinforced polymer (FRP) structures, due to their low mass, are valuable alternatives to traditional steel or concrete structures in seismic areas. However, to resist seismic actions, FRP structures must be able to dissipate a significant amount of inelastic energy. Since FRP materials are brittle, this dissipation must occur in the joints. Monotonic tension and cyclic tension-compression experiments were thus performed on adhesive and bolted double-lap joints composed of pultrude...
#2Alexander Safonov(Skolkovo Institute of Science and Technology)H-Index: 10
Last. Iskander Akhatov(Skolkovo Institute of Science and Technology)H-Index: 20
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Currently, the application of pultruded profiles is increasing owing to their advantages, such as light weight, high strength, improved durability, corrosion resistance, ease of transportation, spe...
Abstract Out-of-plane joints, such as joints between T, I, Z, L and hat (omega) stiffeners and skin panels are essential part of composite structures. To ensure the integrity of these assemblies, the inclusion of a filler material in the junction region between the skin, flanges and web is necessary. The conventional filler is a rolled unidirectional fibre bundle or resin filling, but there are many other proposed methods in the literature. This paper reviews the state-of-the-art work available ...
Abstract This paper presents an experimental study of the quasi-static and fatigue load performance of a pultruded GFRP (glass fiber-reinforced polymer) deck panel that can be used to furnish the roadway surface of temporary detour bridges. The flanges of the GFRP deck panel were reinforced with uniformly spaced steel wires to increase the flexural stiffness of the panel. A total of nine full size GFRP deck panel specimens were tested under static and fatigue loadings. The load-deflection behavi...
