Hybrid Composite Beams Research Articles

Free vibration and buckling analysis of the impacted hybrid composite beams

The aim of this experimental study is to investigate the free vibration and buckling behaviors of hybrid composite beams having different span lengths and orientation angles subjected to different impact energy levels. The impact energies are applied in range from 10 J to 30 J. Free vibration and buckling behaviors of intact and impacted hybrid composite beams are compared with each other for different span lengths, orientation angles and impact levels. In free vibration analysis, the first three modes of hybrid beams are considered and natural frequencies are normalized. It is seen that first and second modes are mostly affected with increasing impact energy level. Also, the fundamental natural frequency is mostly affected with the usage of mold that have 40 mm span length (SP40). Moreover, as the impact energy increases, the normalized critical buckling loads decrease gradually for <TEX>$0^{\circ}$</TEX> and <TEX>$30^{\circ}$</TEX> oriented hybrid beams but they fluctuate for the other beams.

Progressive damage analysis of a rate-dependent hybrid composite beam

A hybrid beam combined of a molded woven fabric beam and over injected or compressive molded short fiber composite material, are manufactured and three point bending tests with different loading rates and two different boundary conditions are performed. Since the experimental results demonstrate a rate dependent behavior of the beam, then to predict its mechanical behavior under different loading velocities two strain rate sensitive progressive damage models have been developed based on Continuum Damage Mechanics approach. For internal reinforcing constituent of the beam which dominated by matrix, the matrix failure index of Hashin-Rotem’s failure criterion was chosen and for outer part which governed by fibers the maximum stress theory is considered as damage initiation indicator. For both models Lapczyk-Hurtado’s approach is followed to capture damage propagation. To account for rate-dependent material properties, where is needed, equations derived from a logarithmic formula, are utilized. The models are applied on the commercial finite element software of ABAQUS using user-written subroutine based on explicit numerical method. The numerical results are verified by the bending tests and it is shown that the numerical results of the proposed models have shown better agreement with experimental results of compressive molding technology than back injected one.

춤이 작은 신형상 고성능 하이브리드 합성보의 휨성능 평가

춤이 작은 신형상 고성능 하이브리드 합성보의 휨성능 평가

Experimental study on bending behavior and seismic performance of hybrid composite beam with new shape

With the increasing construction of high-rise and long-span buildings, composite structure systems have been increasingly studied in various fields. This study presents and evaluates a new concept hybrid composite beam, using monotonic and cyclic tests. 6 bending specimens and 2 beam-to-column connection specimens of the new concept hybrid composite beam were fabricated for bending and seismic performance testing. The bending behavior test results showed that the capacity of the beam stably increased in proportion to the depth of beams and the thickness of steel plates. Also, sufficient maximum moment was secured compared to nominal moment. The seismic performance test results showed that the maximum moment was above the plastic moment, and the connection was intermediate moment frame.

570MPa급 고강도강을 적용한 콘크리트 채움 U형 하이브리드 합성보의 휨거동 및 설계

Staff, SENVEXAbstract - Flexural tests of full-scale concrete-filled U-shape hybrid composite beams were conducted. Ordinary (SS400) and high-strength (SM570) steel plates were used in the web and in the bottom flange of U-shape steel section respectively. The primary objectives were to develop the hybrid section configuration with maximized flexural capacity and to investigate its flexural strength and deformation capacity. All the hybrid test specimens in this study exhibited the plastic moment capacity a nd resonable deformability. It is shown that the plastic stress distribution can be assumed in calculating the flexural strength o f the proposed hybrid composite beams if the plastic neural axis is located within 15% of the total beam depth from the top of the composite slab. The procedure for computing the effective flexural stiffness of hybrid composite beams is also recommended based on test results. Keywords - Hybrid composite beams, U-shape steel section, High-strength steel, Strain compatibility method, Plastic stress distribution method, Plastic neutral axisNote.-Discussion open until October 31, 2016. This manuscript for this paper was submitted for review and possible publication on March 17, 2015; revised January 11, 2016; approved on March 29, 2016.Copyright ⓒ 2016 by Korean Society of Steel Construction

Durability of Hybrid Composite Beam Bridges Subjected to Various Environmental Conditioning

AbstractThe hybrid composite beam (HCB) is a novel idea that combines conventional construction materials (i.e., steel and concrete) with fiber-reinforced polymer (FRP) composites in a new configuration. This hybridization aims to optimize the beam’s structural performance and produce a structural element that is more durable than conventional members. This study examined the durability of a commercial glass FRP (GFRP) laminate that was used to encase the HCB elements in a recently constructed HCB bridge. The E-glass/vinyl ester laminate was subjected to five aging regimes. These conditioning regimes simulated an alkaline attack, a salt attack, a salt attack that was preceded by ultraviolet (UV) irradiation exposure, and sustained stresses that were accompanied by controlled thermal cycles and natural weathering. The durability of the E-glass/vinyl ester laminate was examined in terms of changes that occurred in the ultimate tensile strength. A microstructural analysis was performed on both unconditioned ...

Investigation of the mechanical behavior and vibration characteristics of thin walled glass/carbon hybrid composite beams under a fixed-free boundary condition

ABSTRACTIn the present work, woven fabric glass laminate is modified by interplying high modulus carbon fabric layers for improving the stiffness to weight ratio to enable good performance in dynamic conditions. The glass, carbon, and hybrid of glass/carbon laminates were fabricated with two different stacking sequences by hand layup method and tested for evaluating the mechanical properties with considerable trials. The vibration characteristics of composite beams were experimentally studied by impulse excitation techniques under fixed-free boundary conditions. The stacking sequence of beams influences the mechanical properties and vibration characteristics. The modal response of tested samples are compared and discussed.

Performance and Behavior of Hybrid Composite Beam Bridge in Virginia: Live Load Testing

AbstractThe hybrid composite beam (HCB) system is an innovative structural technology that has been recently used in bridge construction within the U.S. transportation network. This investigation focused on evaluating the in-service performance of a newly constructed HCB bridge superstructure located on Route 205 in Colonial Beach, Virginia. In the live-load-testing program, the bridge superstructure was instrumented with a series of internal and external strain gauges to evaluate the structural response. The test was conducted using tandem axle dump trucks under both quasi-static and dynamic conditions, and results obtained from the experimental investigation were used to determine three key behavior characteristics: lateral load distribution, internal load-sharing behavior, and dynamic load allowance (DLA). With respect to the live load performance, the HCB system relatively conformed to the provisions of the AASHTO specifications for beam-type bridges but did exhibit some characteristics of a flexible ...

신개념 하이브리드 합성보의 휨성능 및 내진성능에 관한 실험적 연구

최근 초고층, 장스팬 건축물이 다수 설계됨에 따라 합성구조시스템에 대한 연구가 여러 분야에서 다양하게 진행되고 있다. 이에 본 연구에서는 단면의 효율을 극대화 시킨 신개념 하이브리드 합성보의 형상을 제안하고, 휨성능 및 내진성능을 평가하기 위해 실물대 크기의 휨 실험체 6개와 기둥-보 접합부 실험체 2개를 제작하여 단조가력 및 반복가력으로 실험을 진행하였다. 휨성능 실험결과 보 춤 및 강판 두께에 비례하여 안정적으로 내력이 증가하였으며, 공칭강도와 비교하여 충분한 최대내력이 확보되었다. 내진성능 실험결과 소성모멘트 이상으로 내력이 확보되었으며, 합성중간모멘트골조의 내진성능을 갖는 것으로 나타났다. Recently, high rise buildings and long span buildings are being constructed, studies on composite structure systems have been progressing in various fields. Therefore, this study suggested the new concept hybrid composite beam and performed the monotonic and cyclic tests to evaluate the bending and seismic performance of the new concept hybrid composite beam by creating 6 bending specimens and 2 beam-to-column connection specimens. The bending performance test results showed that the capacity of the beam was stably increased in proportion to the depth of beams and the thickness of steel plates. Also, enough maximum moment was secured compared to nominal moment. The seismic performance test results showed that the maximum moment is above the plastic moment and the connection is intermediate moment frame.

Flexural behavior of hybrid composite beams with a bamboo layer and lattice ribs

This paper presents an experimental investigation of flexural behavior of hybrid composite beams with glass fiber reinforced plastics box skins, a polyurethane foam core, a bamboo layer, and lattice ribs. The bamboo layer was placed on the top of a wrapped polyurethane foam core. The lattice ribs were distributed along the longitudinal direction of the beam. Four beams, involving a control specimen, were loaded in four-point bending to validate the effectiveness of the bamboo layer and lattice ribs for increasing the ultimate bending strength of the hybrid composite beams. Compared to the control specimen, a maximum of an approximately 85% increase in the ultimate bending strength can be achieved. The beam with bamboo layer reinforcement and without lattice ribs exhibits the highest stiffness-to-weight ratio, while the beam with both bamboo layer and lattice ribs exhibits the highest strength-to-weight ratio. Meanwhile, various failure modes were summarized, including compressive and crushing failures. Finally, an analytical model to predict the bending stiffness and ultimate bending strength of the hybrid composite beams was proposed. Furthermore, the analytical results were agreed well with test results.

Analytical investigation of hybrid composite precast beams with modified strain compatibility for entire history of nominal flexural capacity

SummaryThe strain compatibility documented in Chapter I of the American Institute of Steel Construction 360‐10 (AISC, 2010) was modified to provide accurate analytical solution for hybrid composite precast beams. In the proposed method, locations of neutral axis of the section are investigated to formulate all possible equilibrium equations of stress fields of composite sections. The only neutral axis satisfying all stress fields is then found for composite sections for entire loading history including yield and maximum load limit state and between those limit states. Finally, the nominal moment capacity of hybrid composite precast beam is calculated based on the correct neutral axis. Experimental study was conducted to verify the accuracy of the proposed method. The test results for hybrid composite precast beams agreed very well with the analysis results. The capacity difference between them is less than 4.8%. This study also compares the proposed design method with the conventional strength addition method, showing that the conventional method underestimated structures leading to over‐design. It was found that the new approach predicted the behaviors of hybrid composite precast beams more accurately than the conventional methods. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Geopolymer concrete-filled pultruded composite beams – Concrete mix design and application

The limited research on the geopolymer concrete mix design for targeting a specific strength is identified an obstacle for their effective design and wide use. In this paper, a mix design procedure has been proposed for fly-ash based geopolymer concrete and its use as infill hybrid composite beam is investigated. Then, the structural performance of geopolymer concrete filled hybrid composite beam is investigated to determine their possible application in civil infrastructure. Firstly, a detailed procedure of mix design for fly-ash based geopolymer concrete is presented. Secondly, three hybrid beams filled with geopolymer concrete were prepared and tested in a four-point bending setup to evaluate their flexural modulus and modulus of rupture. Numerical and analytical evaluation of the behaviour of hybrid beam were performed and results showed a good agreement with the experimental investigation. Thirdly, the suitability of the beam for a composite railway sleeper is evaluated and compared with existing timber and composite sleepers. Finally, the beams’ performance in a ballast railway track is analysed using Strand7 finite element simulation software and the results showed that the new concept of using geopolymer concrete as infill to pultruded composite section satisfied the stiffness and strength requirements for a railway sleeper.

Vibration analysis of self-healing hybrid composite beam under moving mass

In this study vibration analysis of hybrid epoxy composite beam under moving mass was investigated. Composite beam was reinforced unidirectional by carbon fibres and Shape Memory Alloy (SMA) wires. There is an open crack in the middle of the beam that is extended transversely in the beam structure and modelled as local flexibility. SMA fibres were embedded longitudinally in the layer of epoxy to heal the defected area by strain recovery. The Timoshenko beam model was used and the beam at the crack area was divided into two segments. Transfer Matrix Method (TMM) was then applied to solve the problem. Various volume fractions of wires in the epoxy were studied and found that, volume fraction of 2.5% can repair the defected beam as healthy one. It was observed that, using high volume fraction of SMA wires can significantly reduce deflection. Moreover, it was achieved SMA wires with volume fraction of 15% is capable to increase natural frequency of cracked beam 9.6%. Stress Intensity Factor (SIF) at the crack tip was studied and the recovery of the mode I SIF as a result of embedded wires revealed. The effect of various volume fractions of SMA wires, mass speed and crack depth were studied as well. There is a proper adjustment between the current results and those which were found through FEM.

Exact Solution for Nonlinear Thermal Stability of Geometrically Imperfect Hybrid Laminated Composite Timoshenko Beams Embedded with SMA Fibers

AbstractThe nonlinear analysis of shape memory alloy (SMA) hybrid composite beams under in-plane thermal load is presented in this paper. The properties of the constituents are assumed to be temperature dependent. The initial imperfection of the beam is also taken into account as an initial deflection function prior to heating. Geometrical nonlinearity is formulated in the von Karman sense. It is assumed that the kinematics of the beam obeys the Timoshenko first-order beam theory and the SMA fibers follow the one-dimensional Brinson constitutive law. These basic assumptions are inserted into the static version of the virtual displacements principle to derive the nonlinear equilibrium equations. The resulting system of equations is uncoupled and solved exactly. Closed-form expressions are presented to trace the equilibrium path of the beam as a function of the uniform heating parameter. It is shown that, in special cases, the induced tensile recovery stress of the SMA fibers may stabilize an imperfect beam...

Natural frequency response of laminated hybrid composite beams with and without cutouts

Abstract This study deals with the effect of hybridization on the natural frequency of woven laminated hybrid composite beams with and without cutouts under the clamped-free boundary condition. Woven carbon, Kevlar and S-glass fibers with epoxy were used for the production of hybrid composites. Natural frequencies of the hybrid composite beams were experimentally determined for [(0/90)3]S stacking sequence. Numerical analyses were performed to investigate the influences of fiber orientation angles, circular and rectangular cutouts, cutout size ratios and positions on natural frequency. Good agreement between experimental and numerical results was found from a comparison of natural frequencies. The results shows that the fiber type used in the layers, cutout size and position on the beam strongly effects the natural frequency.

Investigation on Vibration Behaviour of Cantilever Type Glass/Carbon Hybrid Composite Beams at Higher Frequency Range Using Finite Element Method

Woven fabric composites are now being increasingly used in aircraft and automobile structures due to balanced properties in the fabric plane. In the present work, woven fabric glass beam is modified and strengthened by interplying high modulus carbon fabric plies for improving the strength to weight ratio and thereby to achieve better performance in various dynamic conditions. The objective of the present work is to investigate the vibration behavior of cantilever type glass/carbon hybrid composite beams subjected to higher frequency of operation using finite element method. Unit plied woven fabric glass, carbon and hybrid of glass/carbon laminates were fabricated using hand layup technique. Experimental modal analysis of unit plied composite beams was carried out by impulse excitation technique under fixed free boundary condition. Theoretical modal analysis was done by finite element method using elastic constants derived from rule of mixture equations. The experimental and theoretical frequency results were compared and analyzed for finding the degree of deviation using regression analysis. The coefficients of regression analysis were used to find effective elastic constants of composite laminates. Further these effective elastic constants were applied for modal analysis of hybrid composite beams under higher frequency range. The results of mode shape, modal frequency of hybrid beams were reported and discussed. The effect of stacking sequence and effect of beam size on vibration characteristics at higher frequency range was also discussed.

Nonlinear dynamics of SMA-fiber-reinforced composite beams subjected to a primary/secondary-resonance excitation

In this paper, nonlinear free vibration and primary/secondary resonance analyses of shape memory alloy (SMA) fiber reinforced hybrid composite beams with symmetric and asymmetric lay-up are investigated. The simplified Brinson constitutive model and cosine phase transformation kinetics are utilized to simulate the behavior of the SMA materials and calculate the recovery stress. In order to predict the behavior of the smart laminated beam, Euler–Bernoulli beam theory and nonlinear von-Karman strain field are employed. Two types of micromechanical models, namely Voigt and Reuss models are considered. The Galerkin procedure together with the elliptic function and multi timescales method is adopted to obtain analytical solutions for the nonlinear free vibration and primary/secondary response phenomena. Numerical results reveal that some of the geometrical and physical parameters such as the SMA volume fraction, the amount of prestrain in the SMA fiber, orientation of composite fiber, vibration amplitude and temperature are important factors affecting the free vibration characteristic in the pre/post-buckled region, and primary and secondary resonance of the laminated beams reinforced with SMA fibers. The analytical solutions and results are reported for the first time and can serve as benchmark for researchers to validate their numerical and analytical methods in the future.

Finite-Element Modeling of Hybrid Composite Beam Bridges in Missouri

Three bridges were recently constructed in Missouri using a new type of hybrid composite beam (HCB) incorporated within traditional RC deck systems. These HCBs are comprised of three main subcomponents: a composite shell, compression reinforcement, and tension reinforcement. The compression reinforcement is a self-consolidating concrete (SCC) arch that is tied at the ends by high-strength galvanized steel strands. The compression and tension reinforcements are encapsulated in a glass fiber–reinforced polymer (GFRP) box, and the voids are filled with polyisocyrunate (polyiso) foam. This unique configuration aims to optimize the structural performance of the HCB constituents, hence optimizing the overall performance of the beam. However, because of the novelty of the HCB, its structural behavior is not yet completely understood. Consequently, the finite-element (FE) modeling of this new type of beam is crucial for providing deeper insight into its structural behavior and validating the current design assumptions. It is, therefore, the main goal of this study to examine the accuracy of linear FE analysis (FEA) in predicting the static behavior of the HCB under service loads. This paper explains in detail the FE modeling of the superstructure of one of the recently constructed HCB bridges, using two commercial FEA packages. A field load test that simulates several load cases was applied to the bridge, and the deflections of the HCBs were measured at different locations. A simple analytical procedure that is based on the transformed area method is also used to predict the HCB deflections. The comparison between measured deflections and predicted deflections shows that the FEA can predict the HCB bridge behavior with acceptable accuracy, whereas the theoretical procedure significantly overestimates the beams’ deflections. Finally, the two FE models are used to analyze the behavior of the HCBs.

On the free vibration of thermally pre/post-buckled shear deformable SMA hybrid composite beams

The objective of this article is to analytically investigate the free vibration of shape memory alloy hybrid composite (SMAHC) beams in thermally pre/post-buckled domains. Non-linear equations of motion of SMAHC beams are derived based on the first-order shear deformation theory and von Karman geometrical non-linearity via the extended Hamilton principle. The recovery stress generated by temperature-induced martensitic phase transformation of the pre-strained SMA fibers is computed by means of the Brinson model. Exact closed-form solutions are presented for the buckling temperature, post-buckling deformation and temperature-deformation equilibrium path of symmetric and asymmetric simply supported SMAHC beams under uniform temperature rise. The vibration of the symmetric SMAHC beam around the first buckled configuration is also investigated and an analytical solution for the fundamental frequency and its associated mode shape is obtained. Based on the developed closed-form solutions, extensive numerical results are presented to provide an insight into the influence of SMA fibers volume fraction, pre-strain in the SMA fibers, location of SMA fibers, temperature rise and geometrical parameters on the static and dynamic responses of the SMAHC beams in the thermally pre/post-buckling regimes. Due to the absence of similar results in the specialized literature, this paper is likely to fill a gap in the state of the art of this problem.

Bending response of hybrid composite tubular beams

The influence of inner and outer reinforcements on the bending performance of a thin walled aluminum tube was investigated. Polymeric materials (PA6, PP) and glass/carbon fiber reinforced epoxy were considered to form the composite beam for the inner and outer reinforcement, respectively. The experimental results indicated that the outer reinforcement with a [02/903] fiber orientation layout increased the collapse load by a factor of 4.5 and 5.3. In the hybrid composite beam (HCB), load carrying capacity (LCC) increased a maximum of 14 times. Load carrying capacity of HCB is 2.5 times higher than the steel tube that is used in automotive industry.