scholarly journals Dynamic tests of composite footbridge segment – experimental and numerical studies

2019 ◽  
Vol 285 ◽  
pp. 00021 ◽  
Author(s):  
Tomasz Wiczenbach ◽  
Tomasz Ferenc ◽  
Łukasz Pyrzowski ◽  
Jacek Chróścielewski
Keyword(s):  
Numerical Model ◽  
Cross Section ◽  
Natural Frequencies ◽  
Foam Core ◽  
Span Length ◽  
Dynamic Tests ◽  
Numerical Studies ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Dynamic Excitations

Experimental dynamic tests and numerical simulations of a 3 meters long segment of a footbridge made of polymer composites are presented in the paper. The span-length is reduced, however dimensions of cross-section are the same as the target footbridge. The segment structure is made of sandwich panels, which consist of fibre reinforced polymer (GFRP) laminates (skins) and a PET foam (core). The first part of the paper contains description and results of experimental dynamic tests, which were subjected to the structure. The excitations during these tests was realised by a group of people standing or jumping on the structure deck. The obtained results allowed to determine natural frequencies as well as damping ratios. Moreover, cyclic loading was applied to the structure deck to check the possibility of delamination or debonding occurrence, as a result of repetitive dynamic excitations. The second part contains validation of numerical model - results of numerical analysis and its comparison with the experimental ones.

scholarly journals The Effect of Glue Cohesive Stiffness on the Elastic Performance of Bent Wood–CFRP Beams

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5075
Author(s):  
Bartosz Kawecki ◽  
Jerzy Podgórski
Keyword(s):  
Elastic Stiffness ◽  
Theoretical Modelling ◽  
Joint Analysis ◽  
Adhesive Layers ◽  
Numerical Studies ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Precise Prediction ◽  
Equivalent Area

This paper presents experimental, theoretical and numerical studies of wood-CFRP beams bonded with polyurethane (PUR) adhesive. The analyses include two types of CFRP (carbon fibre-reinforced polymer) strengthening configurations and pure glue laminated timber beams as a reference. Through detailed analyses of a double-lap connection on blocks with and without CFRP strips, the authors state that neglecting the cohesive stiffness of adhesive layers may lead to an overestimation of an overall beam’s stiffness. This is significant with wood–CFRP connections, which showed values two times lower than with wood–wood connections. Theoretical modelling of the equivalent area used in a theory of composites provided much stiffer behaviour of the beams than in laboratory experiments. It proves that a PUR glue eliminates the possibility of using simple models that assume a perfect connection between bonded parts. These conclusions led the authors to use the finite element method (FEM) to take into account the cohesive stiffness. The FEM, based on the properties obtained from a double-lap joint analysis, allowed for the precise prediction of the elastic stiffness of the beams.

scholarly journals A Comparative Analysis on the Methods of Strengthening Isolated Reinforced Concrete Columns

2021 ◽  
Vol 1203 (2) ◽  
pp. 022037
Author(s):  
Mungur Ved Vritesh ◽  
Seeboo Asish
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Wire Mesh ◽  
Steel Plates ◽  
Experimental Investigations ◽  
Cross Sectional ◽  
Short Columns ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

Abstract In the construction industry, there are several methods which have been used to improve the capacity and effectiveness of structural concrete structures. Engineers can extend the life of the structures by implementing strengthening techniques. One of the techniques to strengthen columns and beams is the use of jacketing. The strength of the structural members is enhanced through the surface structural bonding of materials such as Carbon-Fibre Reinforced Polymer (CFRP), Glass-Fibre Reinforced Polymer (GFRP), ferrocement, steel angles, steel plates, wire mesh and so on. In this study, 18 reinforced concrete short columns of cross-sectional size 60 mm × 60 mm and 500 mm height were cast using concrete grade 30 MPa. The columns were subjected to compressive axial loads till failure. Moreover, the damaged columns were strengthened using three structural strengthening techniques namely, Reinforced Concrete Jacketing (RCJ), Reinforced Concrete Wire Mesh Jacketing (RCWJ) and, Steel Jacketing (SJ). The columns strengthened using RCJ and RCWJ had a cross section of 120 mm × 120 mm while SJ had a cross section of 66 mm × 66 mm. Six different configurations were used for each technique. The experimental investigations showed a minimum increase of 48.0%, 48.7% and 35.2% in the axial compressive strength when strengthened using RCJ, RCWJ and SJ respectively. Among the three strengthening techniques, SJ was determined to be the effective technique on considering structural design, time production and costs.

Numerical Modeling of Energy Absorption Behaviour of Aluminium Foam Cored Sandwich Panels with Different Fibre Reinforced Polymer (FRP) Composite Facesheet Skins

2016 ◽  
Vol 852 ◽  
pp. 66-71 ◽  
Author(s):  
M. Nalla Mohamed ◽  
D. Ananthapadmanaban ◽  
M. Selvaraj
Keyword(s):  
Energy Absorption ◽  
High Velocity ◽  
Sandwich Panels ◽  
Aluminium Foam ◽  
Foam Core ◽  
High Velocity Impact ◽  
Velocity Impact ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
The Impact

Sandwich structures based on Fibre Reinforced Polymer (FRP) facesheet skins bonded with low density aluminium foam core are increasing in use in aerospace and marine industries. These structures are very sensitive to high velocity impact during the service. Therefore, it is necessary to study the energy absorption of the structures to ensure the reliability and safety in use. Experimental investigation of these transient events is expensive and time-consuming, and nowadays the use of numerical approaches is on the increase. Hence, the purpose of this paper is to develop a numerical model of sandwich panels with aluminium foam as a core and Glass, Carbon and Kevlar Fibre Reinforced polymer composite as faceplate, subjected to high velocity impact using ABAQUS/Explicit. The influence of individual elements of the sandwich panel on the energy absorption of the structures subjected to high velocity impact loading was analysed. Selection of suitable constitutive models and erosion criterion for the damage were discussed. The numerical models were validated with experimental data obtained from the scientific literature. Good agreement was obtained between the simulations and the experimental results. The contribution of the face sheet, foam core on the impact behaviour was evaluated by the analysis of the residual velocity, ballistic limit, and damaged area.

scholarly journals The effect of nylon nanofibers on the dynamic behaviour and the delamination resistance of GFRP composites

2018 ◽  
Vol 148 ◽  
pp. 14001 ◽  
Author(s):  
Cristobal Garcia ◽  
Irina Trendafilova ◽  
Andrea Zucchelli ◽  
Justin Contreras
Keyword(s):  
Composite Materials ◽  
Dynamic Behaviour ◽  
Natural Frequencies ◽  
Damping Ratio ◽  
Gfrp Composites ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Delamination Resistance ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced

Vibrations are responsible for a considerable number of accidents in aircrafts, bridges and other civil engineering structures. Therefore, there is a need to reduce the vibrations on structures made of composite materials. Delamination is a particularly dangerous failure mode for composite materials because delaminated composites can lose up to 60% of their strength and stiffness and still remain unchanged. One of the methods to suppress vibrations and preventing delamination is to incorporate nanofibers into the composite laminates. The aim of the present work is to investigate how nylon nanofibers affect the dynamic behaviour and delamination resistance of glass fibre reinforced polymer (GFRP) composites. Experiments and numerical simulations using finite element modelling (FEM) analysis are used to estimate the natural frequencies, the damping ratio and inter-laminar strength in GFRP composites with and without nylon nanofibers. It is found that the natural frequencies of the nylon nano-modified composites do not change significantly as compared to the traditional composites. However, nano-modified composites demonstrated a considerable increase in damping ratio and inter-laminar shear strength due to the incorporation of nylon nanofibers. This work contributes to the knowledge about the mechanical and dynamic properties of glass fibre reinforced polymer (GFRP) composites with nylon nanofibers.

Flexural and axial behaviour of sandwich panels with bio-based flax fibre-reinforced polymer skins and various foam core densities

2016 ◽  
Vol 20 (5) ◽  
pp. 595-616 ◽  
Author(s):  
Luke CoDyre ◽  
Kenneth Mak ◽  
Amir Fam
Keyword(s):  
Sandwich Panels ◽  
Single Layer ◽  
Flax Fibre ◽  
Foam Core ◽  
Core Density ◽  
Axial Capacity ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Stub Column ◽  
Glass Frp

This study investigates the effect of foam core density on the behaviour of sandwich panels with novel bio-composite unidirectional flax fibre-reinforced polymer skins, along with a comparison to panels of conventional glass-FRP skins. Eighteen 1000 mm long flexural specimens and 18 500 mm long stub column specimens were fabricated and tested. All specimens had a foam core of 100 × 50 mm2 cross-section with symmetrical 100 mm wide skins. The study compares the effect of three separate polyisocyanurate foam cores when used in conjunction with either three layers of flax fibre-reinforced polymer or a single glass-FRP layer for each skin. Flexural specimens were tested in four-point bending and stub columns were tested under axial compression with pin–pin end conditions. Doubling the core density from 32 to 64 kg/m3 and tripling the density to 96 kg/m3 led to flexural strength increases of 82 and 213%, respectively, for flax fibre-reinforced polymer skinned panels, and comparable increases in glass-FRP skinned panels. Similarly, flax fibre-reinforced polymer-skinned columns showed similar increases in ultimate axial capacity of 85% and 196%, while glass-FRP- skinned columns experienced lower increases when core density was varied. The three-layered flax fibre-reinforced polymer skin, only 17% thicker than the single layer glass-FRP skin, was shown to provide equivalent flexural and axial strengths at all three core densities, within −5 to +13%.

Structural Performance of a New Column’s Prototype Made by FRP Pultruded Material and Light Concrete

2014 ◽  
Vol 900 ◽  
pp. 468-472 ◽  
Author(s):  
Giosuè Boscato
Keyword(s):  
Bond Strength ◽  
Cross Section ◽  
Structural Performance ◽  
The Novel ◽  
The Core ◽  
Reinforced Polymer ◽  
First Case ◽  
Fibre Reinforced Polymer ◽  
Concrete Casting ◽  
Separate Material

This investigation presents some evaluation based on the experimental and numerical results obtained on the compression bearing capacity of new columns prototype made by FRP (Fibre Reinforced Polymer) material and concrete. In detail that is the junction due to the assembly between hollow FRP profiles made by pultrusion process with glass fibres and thermosetting matrix vinylestere, and very light concrete casting inside. To better understand the eventually influence related to the hollow shape employed, the study consider both the case of circular and square profile. Due to the novel of the research, a not negligible part of the research is dedicated to test previous the separate material, that is the plane concrete and the hollow GFRP profile, and then the prototype (concrete+GFRP) also considering two different way of load application. Particularly we applied in the first case the load to only the core of the sample, on the plane concrete, and then to the total cross section. This choice allows to evaluate the role and the influence of the bond strength along the length of each sample.

The effect of prestress force magnitude on the natural bending frequencies of the eccentrically prestressed glass fibre reinforced polymer composite beams

2017 ◽  
Vol 52 (15) ◽  
pp. 2115-2128 ◽  
Author(s):  
Anita Orlowska ◽  
Cezary Graczykowski ◽  
Adam Galezia
Keyword(s):  
Natural Frequencies ◽  
Epoxy Composite ◽  
Composite Beams ◽  
Theoretical Background ◽  
Force Magnitude ◽  
Prestressing Force ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced

This paper studies the effect of prestress force magnitude on natural frequencies and dynamic behaviour of eccentrically prestressed glass fibre reinforced polymer composite beams, including the theoretical background, numerical results and experimental verification. The term prestress indicates the initial tensile stress applied to the fibres embedded in selected external layers of the composite material. First, the paper presents the theoretical background of the finite element method modelling of prestressed composites. Then, the results of numerical simulations conducted for a five-layered glass-epoxy composite beam are presented. The natural frequencies corresponding to three initial bending modes are analyzed for different prestressing force levels and for different fibre volume content. Finally, the results are verificated by experimental modal analysis conducted on three different glass-epoxy composite specimens of various mechanical parameters. Both the numerical results obtained from finite element method and the experimental results obtained from experimental modal analysis reveal that the first bending frequency increases and the two subsequent bending frequencies decrease due to the prestressing force. The comparison of numerical and experimental data confirms the effect and allows to quantify the influence that the prestress force has on the natural frequencies of composites, which is an interesting and practically relevant phenomenon.

Flexural behaviour of fibre-reinforced polymer–aluminium sandwich curtain walls

2017 ◽  
Vol 20 (7) ◽  
pp. 783-810
Author(s):  
Yang Liu ◽  
JS Kuang ◽  
BYB Chan
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Large Scale ◽  
Foam Core ◽  
Flexural Behaviour ◽  
Curtain Wall ◽  
Material Layer ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Change Material

A new type of fibre-reinforced polymer–aluminium sandwich curtain wall panel, which consists of layers of aluminium plate, fibre-reinforced polymer plate, foam core and gypsum board, was proposed to achieve high strength and stiffness, efficient energy saving and good fire resistance for the modern curtain wall systems in buildings. An experimental study was conducted to investigate the flexural behaviour of the fibre-reinforced polymer–aluminium composite curtain wall panels. Three groups of large-scale specimens with different thickness of foam core with and without a phase change material layer were tested under uniformly distributed loads. The test results showed that due to the asymmetric arrangement of sandwich layers, the loading directions had a significant effect on the flexural behaviour of the panels with and without a phase change material layer. It was also shown that with the increase of the foam core thickness, the flexural behaviour of panels was significantly improved. In addition, the phase change material layer had little effect on the flexural behaviour of the sandwich panels under and beyond the serviceability conditions, but significantly reduced the serviceability strength.

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