scholarly journals Strengthening of Hollow Square Sections under Compression Using FRP Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-19 ◽  
Author(s):  
M. C. Sundarraja ◽  
P. Sriram ◽  
G. Ganesh Prabhu
Keyword(s):  
Failure Modes ◽  
Deformation Behaviour ◽  
Three Dimensional ◽  
Local Buckling ◽  
Experimental Results ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

The feasibility study on carbon fibre reinforced polymer (CFRP) fabrics in axial strengthening of hollow square sections (HSS) was investigated in this paper. CFRP was used as strips form with other parameters such as the number of layers and spacing of strips. Experimental results revealed that the external bonding of normal modulus CFRP strips significantly enhanced the load carrying capacity and stiffness of the hollow sections and also reduced the axial shortening of columns by providing external confinement against the elastic deformation. The increase in the CFRP strips thickness effectively delayed the local buckling of the above members and led to the inward buckling rather than outward one. Finally, three-dimensional nonlinear finite element modeling of CFRP strengthened hollow square sectionswas created by using ANSYS 12.0 to validate the results and the numerical results such as failure modes and load deformation behaviour fairly agreed with the experimental results.

scholarly journals BEHAVIOUR OF CFST MEMBERS UNDER COMPRESSION EXTERNALLY REINFORCED BY CFRP COMPOSITES

2013 ◽  
Vol 19 (2) ◽  
pp. 184-195 ◽  
Author(s):  
M. C. Sundarraja ◽  
G. Ganesh Prabhu
Keyword(s):  
Failure Modes ◽  
Axial Stress ◽  
Constant Width ◽  
Local Buckling ◽  
Steel Tube ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Externally Bonded ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This research is aimed at investigating the structural improvements of concrete filled steel tubular (CFST) sections with normal strength concrete externally bonded with fibre reinforced polymer (FRP) composites. For this study, compact mild steel tubes were used with the main variable being FRP characteristics. Carbon fibre reinforced polymer (CFRP) fabrics was used as horizontal strips (lateral ties) with several other parameters such as the number of layers and spacing of strips. Among twenty one columns, eighteen were externally bonded by CFRP strips having a constant width of 50 mm with a spacing of 20 mm and 40 mm and the remaining three columns were unbounded. Experiments were undertaken until column failure to fully understand the influence of FRP characteristics on the compressive behaviour of square CFST sections including their failure modes, axial stress-strain behaviour, and enhancement in load carrying capapcity. It was found that the external bonding of CFRP strips provides external confinement pressure effectively and intended to delay the local buckling of steel tube and also to improve the load carrying capacity further.

Micromechanical Modelling of Elliptic Vibration-Assisted Cutting of Unidirectional FRP Composites

2012 ◽  
Vol 591-593 ◽  
pp. 531-534 ◽  
Author(s):  
Wei Xing Xu ◽  
L.C. Zhang ◽  
Yong Bo Wu
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Elliptic Vibration ◽  
Dimensional Finite Element ◽  
Chip Size ◽  
Fibre Reinforced Polymer ◽  
Good Potential ◽  
Three Dimensional Finite Element

Fibre-reinforced polymer (FRP) composites have been widely used in industry. However, the machining of FRP products is difficult, because of very different properties of the fibres and matrix. This paper discusses the development and implementation of a microstructure-based three-dimensional finite element model for the elliptic vibration-assisted (EVA) cutting of unidirectional FRP composites. The results showed that the EVA cutting has a good potential to the machining of FRP composites, featured a much reduced cutting force, better surface integrity and controllable chip size.

scholarly journals Synergetic effects of carbon nanotube-graphene nanoplatelet hybrids in carbon fibre reinforced polymer composites

2018 ◽  
Vol 188 ◽  
pp. 01015 ◽  
Author(s):  
Magda Silva ◽  
Diogo Vale ◽  
Jéssica Rocha ◽  
Nuno Rocha ◽  
Raquel Miriam Santos
Keyword(s):  
Carbon Fibre ◽  
Mechanical Performance ◽  
Synergistic Effects ◽  
Three Dimensional ◽  
Hybrid Filler ◽  
Synergetic Effects ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
3D Architecture ◽  
Fibre Reinforced Polymer

Hybrid filler systems of carbon-based nanoparticles with different geometry shapes, one-dimensional (1D-) carbon nanotubes (CNTs) and two-dimensional (2D-) graphene nanoplatelets (GnPs), were dispersed into epoxy matrix, using an intensive mixer, to evaluate their promising synergistic effects. In this work, the influence of different CNT/GnP ratios on the dispersion level, electrical and mechanical performance of epoxy-based nanocomposites was investigated. It was found that the size and number of GnP agglomerates are significantly reduced with the incorporation of CNTs, due to the formation of a co-supporting three-dimensional (3D-) architecture that delays re-agglomeration of the nanoplatelets. The combination of CNTs and GnPs, at an overall concentration of 0.043 wt. %, synergistically increase the mechanical performance and reduce the electrical percolation threshold of nanocomposites comparatively to the single filled systems. The transversal tensile properties, including elastic modulus – E2 and failure strength – Yt, of carbon fibre reinforced polymer (CFRP) composites were studied and synergetic effects were also found when combining CNTs with GnPs.

Evaluation of Bonding between High Modulus CFRP Sheet and Steel after Environmental Exposure and Fatigue Loading

2014 ◽  
Vol 891-892 ◽  
pp. 143-148
Author(s):  
Hong Bo Liu ◽  
Daniel Borrie ◽  
Xiao Ling Zhao ◽  
Yu Bai ◽  
R.K. Singh Raman
Keyword(s):  
Failure Modes ◽  
Sea Water ◽  
Fatigue Loading ◽  
Reinforced Polymer ◽  
Cfrp Sheet ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Loading Tests ◽  
Number Of Cycles ◽  
Steel Joints

This study investigated the effects of fatigue loading and corrosive environment on bonding strength and failure modes of Carbon Fibre Reinforced Polymer (CFRP)-laminated steel. A series of tests on CFRP bonded steel plate joints was conducted. The joints were immersed in the temperature controlled sea-water with a preload. After immersions for one and six months, they were subjected to cyclic loading for a pre-set number of cycles, and then tensioned to failure. The effect of fatigue loading alone was studied by the authors in the past. In the present study, the results of the cyclic and static loading tests were compared. The comparisons between the current and previous results have provided data on the durability of CFRP/steel joints under this environmental condition.

scholarly journals EXPERIMENTAL AND ANALYTICAL INVESTIGATION OF THE EFFECT OF FIBRE REINFORCED POLYMER ON THE SHEAR STRENGTH OF REINFORCED CONCRETE BEAMS

2020 ◽  
Vol 4 (3) ◽  
pp. 60-71
Author(s):  
Nurudeen Yusuf ◽  
J. M. KAURA ◽  
A. Ocholi ◽  
M. Abbas ◽  
A. Mohammed
Keyword(s):  
Shear Strength ◽  
Carbon Fibre ◽  
Experimental Results ◽  
Rc Beams ◽  
Cfrp Laminate ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Analytical Results ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper presents the experimental and analytical results of the contribution of carbon fibre reinforced polymer (CFRP) laminates to the shear strength of RC beams. To assess the efficiency of the carbon fibre reinforced polymer (CFRP)  laminates on the strengthened specimens, twelve identical beams of cross-sectional dimensions 150x150x750mm were cast, out of which three are un-strengthened and nine were strengthened with U-wrap strips at 100 mm away from each support at varying CFRP laminates layers of  single, double and triple amounts. The prepared specimens were subjected to a three-point bending test. The results obtained revealed that the CFRP laminate increased the shear strength of the strengthened specimens over the control (un-strengthened) by 35.06%, 54.40% and 69.30% for single, double and triple layers of CFRP laminate respectively. The experimental results was also compared with the analytical results obtained based on the equation proposed by Khalifa et al., 1998. The analytical results obtained from the equation closely agreed with the experimental results. Therefore, it implies that the CFRP has the potentials of strengthening shear defiant RC beams.

scholarly journals Investigation on Corroded Hss Tubular Members under Compression Strengthened with CFRP Composites

2014 ◽  
Vol 60 (1) ◽  
pp. 145-159 ◽  
Author(s):  
M.C. Sundarraja ◽  
P. Sriram
Keyword(s):  
Failure Modes ◽  
Axial Stress ◽  
Constant Width ◽  
Structural Behaviour ◽  
Steel Tubes ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Tubular Sections

Abstract The main objective of this investigation is to assess the feasibility of strengthening of corroded (damaged) square hollow steel tubular sections subjected to compression and to develop or predict the suitable wrapping scheme of fibre reinforced polymer (FRP) to enhance the structural behaviour of it. For this study, compact mild steel tubes were used with the main variable being FRP characteristics. Carbon fibre reinforced polymer (CFRP) fabrics was used as horizontal strips (lateral ties) with other parameters such as the number of layers and spacing of strips. Among fourteen specimens, six were externally bonded by CFRP strips having a constant width of 50mm with a spacing of 20mm and the remaining six were externally bonded by CFRP strips having a constant width of 70mm with a spacing of 20mm, two columns were unbonded. Experiments were undertaken until the failure of columns to fully understand the influence of FRP characteristics on the compressive behaviour of the square sections including their failure modes, axial stress-strain behaviour, enhancement in the load carrying capapcity, and effect of distribution of CFRP layers. Finally, the behaviour of externally bonded hollow tubular sections was compared with one another and also with the control specimens. Evaluation of the results will lead to optimum CFRP jacketing/ wrapping arrangements for the steel tubes considered here.

scholarly journals DESIGN AND ANALYSIS OF COMPOSITE LEAF SPRING

2020 ◽  
Vol 15 (3) ◽  
Author(s):  
Prasanna Nagasai B ◽  
Srikanth S ◽  
Tarun D
Keyword(s):  
Experimental Results ◽  
Leaf Spring ◽  
Element Analysis ◽  
Reinforced Polymer ◽  
Light Commercial Vehicle ◽  
Glass Fibre Reinforced Polymer ◽  
Load Carrying ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
D Model

This paper describes the design and experimental analysis of composite leaf spring made of glass fibre reinforced polymer. The main aim is to compare the load-carrying capacity, stiffness and weight savings of composite leaf spring with that of steel leaf spring. The design constraints are stress and deflection. The dimensions of an existing conventional steel leaf spring of a light commercial vehicle were considered for the present work. A traditional composite multi-leaf spring was fabricated with the same dimensions using E- Glass/Epoxy unidirectional laminates. Static analysis of 2D model of conventional leaf spring has also been performed using ANSYS 10 and compared with experimental results. Finite element analysis with a full load on the 3-D model of composite multileaf spring was performed using ANSYS, and the analytical results were compared with experimental results

Numerical prediction of damage mechanisms of E-Glass/epoxy composite material against ballistic impact of 7.62 MS projectile

2020 ◽  
pp. 204141962096702
Author(s):  
Venkata Ramudu Bodepati ◽  
Jayarami Reddy C ◽  
Madhu Vemuri
Keyword(s):  
Composite Material ◽  
Failure Modes ◽  
Epoxy Composite ◽  
Damage Mechanism ◽  
Ballistic Impact ◽  
Experimental Results ◽  
Analytical Models ◽  
Specific Strength ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer

The fibre reinforced polymer matrix composite materials have acquired more credibility over other materials like metals and ceramics due to their high specific strength. Numerical simulations of ballistic impact of 7.62 mild steel projectile on various thicknesses of plain woven E-Glass/epoxy composite material were performed. Residual velocity and ballistic limit of the composite material were determined numerically and the results are compared with that of experiments published elsewhere. The numerical and experimental results are in good agreement. The numerical results are also compared with Recht-Ipson (R-I) and Gellert et al analytical models and are found to be in good correlation. Various failure mechanisms such as two stage damage mechanism namely dishing in target materials less than 10mm and indentation followed by dishing in target materials greater than 10 mm, delamination, and fibre and matrix failure modes of the composite material were studied and compared with the analytical models and experimental results. The wave propagation mechanisms and the damage phenomena are also studied and correlated.

scholarly journals Local Failure Modes and Critical Buckling Loads of a Meta-Functional Auxetic Sandwich Core for Composite Bridge Bearing Applications

2021 ◽  
Vol 11 (22) ◽  
pp. 10844
Author(s):  
Pasakorn Sengsri ◽  
Sakdirat Kaewunruen
Keyword(s):  
Failure Modes ◽  
Three Dimensional ◽  
Local Buckling ◽  
Weight Ratio ◽  
Experimental Results ◽  
Buckling Loads ◽  
Numerical Predictions ◽  
Composite Bridge ◽  
Bridge Bearing ◽  
Sandwich Core

This paper presents a novel meta-functional auxetic unit (MFAU) cell designed to improve performance and weight ratio for structural bridge bearing applications. Numerical investigations were conducted using three-dimensional finite element models validated by experimental results. The validated models were exposed to compression and buckling actions to identify structural failure modes, with special attention placed on the global behaviours of the meta-functional auxetic (MFA) composite bridge bearing. This bearing uses an unprecedented auxetic sandwich core design consisting of multiple MFAU cells. Numerical predictions of the elastic local critical buckling loads of the MFAU cell were in excellent agreement with both the analytical and experimental results, with an observed discrepancy of less than 1%. These results demonstrate that local buckling failures of MFAU cells can potentially be incurred prior to yielding under compression due to their slenderness ratios. Surprisingly, the designed sandwich core used in the MFA composite bridge bearing model can mimic an auxetic structure with significant crashworthiness, implying that this novel core composite structure can be tailored for structural bridge bearing applications. Parametric studies were thus carried out in order to enrich our insight into the MFA composite elements. These insights, stemming from both experimental and numerical studies, enable a novel design paradigm for MFAU that can significantly enhance the structural performance of MFA composite bridge bearings in practice.

scholarly journals EFFECT OF USING EXTERNAL GFRP PLATES ON STRUCTURALLY DEFICIENT RC BEAMS

2003 ◽  
Vol 9 (1) ◽  
pp. 36-44
Author(s):  
Hau Y. Leung ◽  
Ramapillai V. Balendran
Keyword(s):  
Failure Modes ◽  
Experimental Results ◽  
Deformation Capacity ◽  
Rc Beams ◽  
Four Point Bending ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
Strength And Deformation

This paper presents some experimental results on the behaviour of flexure- and shear-deficient RC beams strengthened with external glass fibre reinforced polymer (GFRP) plates. Ten number of 2,5 m long over-designed, unplated under-design and plated under-designed beams were examined under four-point bending condition. Experimental results indicated that use of GFRP plates enhanced the strength and deformation capacity of the structurally deficient beams by altering their failure modes. Application of side plates on shear-deficient RC beams appeared to be more effective than using bottom plates on flexure-deficient RC beams. However, without any improvement on concrete compressive capacity, additional shear capacities provided to the beams under the action of side plates increased the likelihood of beam failure by concrete crushing. Simultaneous use of bottom and side plates on flexure- and shear-deficient RC beams could result in reduced deflection. The change in the neutral axis depth and GFRP strain was also addressed.

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