Composite Beam Model Research Articles

FINITE ELEMENT MODELING OF STEEL-CONCRETE COMPOSITE BEAMS STRENGTHENED WITH PRESTRESSED CFRP PLATE

Results from finite element modeling (FEM) of large-scale steel-concrete composite beams strengthened in flexure with prestressed carbon fiber-reinforced polymer (CFRP) plate were validated with experimental results and presented in this paper. The effect of varying the level of prestressing as percentage of the ultimate tensile strength of the CFRP plate was investigated. Comparison was carried out in terms of overall load-deflection behavior, strain profile along the length of the CFRP plate, and strain distribution across the depth of the beam at mid-span section. Very good agreement was observed between the finite element (FE) and the experimental results. The validated FE models were used to perform a comprehensive parametric study to investigate the changes in the behavior through wider range of prestressing levels and then, determine the optimum prestressing level that maintain the unstrengthened beams' original ductility (or energy absorption). An iterative analytical model was also developed, validated with both the FE model and the experimental results, and showed good agreement. A parametric study was carried out to investigate the effect of changing the yield strength of the steel and the concrete compressive strength on the moment of resistance of the section and the strain in the CFRP plate at ultimate.

Three-dimensional Nonlinear Coupled Model of Galfenol-driven Composite Cantilever Beam Based on Anisotropy

The three-dimensional nonlinear distribution of the magnetic field is studied by using Maxwell equations.The nonlinear magneto-mechanical coupled model is obtained by coupling the nonlinear constitutive model of Galfenol alloy with the structural beam model.The coupled model is implemented in weak form equations.Simulations show that the maximum value of flux density shows up close to the fix end.The strain of the cantilever beam has a similar distribution as the flux density.Experimental researches are conducted by using nonperiodic step signal and periodic sinusoid signal,respectively.It is shown that the calculation results from the model are in good agreement with the experimental data.The proposed model can predict the dead zone,the linear region and the saturation region of the experimental data accurately.Also,it is shown that there are small drifts in the step response of the composite beam due to the existence of sub-harmonic disturbance.It can be seen from the model response that the proposed model can predict the drifts in step response as well.

Variational multiscale approach to enforce perfect bond in multiple-point constraint applications when forming composite beams

Composite laminates that consist of two or more layers find widespread applications in a variety of engineering structures. In the computational modelling of composite laminates, the layers can be stacked together and connected conveniently at the nodes by using multiple-point constraints (MPCs). However, this type of modelling leads to weakening of the kinematic constraint conditions imposed by the bond between the juxtaposed layers and as a consequence, MPCs application at the nodes produces behaviour that is softer than the perfectly bonded composite beam behaviour. The work herein shows that when kinematic conditions for composite action are weakly imposed in the variational form, they can be enforced in the point-wise sense by proper selection of the interpolation field or otherwise reinforced by using variational multiscale approach without modifying the kinematic model. The originality of the approach presented herein is in the interpretation of the MPCs application as the solution in a superfluously extended space because of the weakening in the kinematic constraints. It is shown that the perfect bond between the composite beam layers can be recovered by excluding the identified fine-scale effect from the solution of the multiple point constraint application. The convergence characteristic of the finite element formulation is also improved by using the variational multi-scale approach. It is also shown that the fine-scale effects can be represented by using extra fictitious elements and springs, which offers a direct correction technique in modelling of composite beams that is especially useful when access to the numerical procedure is limited.

Research on Impact Factor of Simple Composite Box Beam under Vehicle Loads

Commonly the vibration due to vehicle loads has no apparently impact on highway bridges, but it is unneglectable when the heavy vehicles load on highway bridges. The impact factor is usually used to define the dynamic effect under vehicle loads in most design code. In this paper, the models of simple composite box beams with different span and the models of two simplified heavy vehicles are established respectively. The impact factors are calculated when the heavy loads pass though bridges at different speed under different load conditions. In addition, the change laws of the impact factors and the influence of different vehicle models on the impact factors are analyzed. Analysis results show that, not only the impact factor are increased with vehicle speed, but also the amplitude and period are all increased. In normal speed range, the influence of speed on the impact factors appears rising trend overall. For the bridge with same span, the impact factors under the double wheel load are smaller than that under single wheel load.

Design and Fabrication of a PZT Cantilever for Low Frequency Vibration Energy Harvesting

In this study, a PZT cantilever with a Si proof mass is designed and fabricated for a low frequency energy harvesting application. A mathematical model of a multi-layer composite beam was derived and applied in a parametric analysis of the piezoelectric cantilever. Finally, the dimensions of the cantilever were determined for the resonant frequency of the cantilever. Our cantilever design was based on MATLAB and ANSYS simulations. For this simulation, the proof mass volumes were varied from 0 to 0.5 mm3 and resonant frequencies were calculated from 833.5 Hz to 125.5 Hz, respectively. Based on simulation, we fabricated a device with beam dimensions of about 4.10 mm x 0.48 mm x 0.012 mm, and an integrated Si proof mass with dimensions of about 0.481 mm x 0.48 mm x 0.45 mm. The resonant frequency, maximum peak voltage, and highest average power of the cantilever device were 224.8 Hz, 4.8 mV, and 2.24 nW, respectively.

MEMS 공정을 이용한 마이크로 PZT 외팔보 에너지 수확소자의 제작 및 특성

In this work, we designed and fabricated a multilayer thin film Pb(Zr,Ti)<TEX>$O_3$</TEX> cantilever with a Si proof mass for low frequency vibration energy harvesting applications. A mathematical model of a mu lti-layer composite beam was derived and applied in a parametric analysis of the piezoelectric cantilever. Finally, the dimensions of the cantilever were determined for the resonant frequency of the cantilever. W e fabricated a device with beam dimensions of about 4,930 <TEX>${\mu}M$</TEX> <TEX>${\times}$</TEX> 450 <TEX>${\mu}M$</TEX> <TEX>${\times}$</TEX> 12 <TEX>${\mu}M$</TEX>, and an integrated Si proof mass with dimensions of about 1,410 <TEX>${\mu}M$</TEX> <TEX>${\times}$</TEX> 450 <TEX>${\mu}M$</TEX> <TEX>${\times}$</TEX> 450 <TEX>${\mu}M$</TEX>. The resonant frequency, maximum peak voltage, and highest average power of the cantilever device were 84.5 Hz, 88 mV, and 0.166 <TEX>${\mu}Wat$</TEX> 1.0 g and 23.7 <TEX>${\Omega}$</TEX>, respectively. The dimensions of the cantilever were determined for the resonance frequency of the cantilever.

Variational asymptotic modeling of composite beams with spanwise heterogeneity

This paper is concerned with modeling composite beams with spanwise heterogeneity. We first formulate the original three-dimensional problem in an intrinsic form which admits a geometrically exact formulation. Taking advantage of slenderness of beam structure and smallness of heterogeneity, we use the variational asymptotic method to systematically obtain an effective beam model through simultaneous homogenization and dimensional reduction. This approach is implemented in the commercial code VABS using the finite element technique for the purpose of dealing with composite beams with spanwise heterogeneity in real applications. A few examples are used to demonstrate the capability of this new model.

Study of Stress Amplitude along the Welding Seam in the Composite Cellular Beam with Eye-Shaped Openings

The behaviour of composite cellular floor beams is becoming important as such members are increasingly used in multistory buildings. But, in the design of some special cellular beam with sharp corner web holes such as eye-shaped openings, the issue of low cycle fatigue failure becomes increasingly critical. In this paper, three-dimensional nonlinear finite element models of composite cellular floor beams with eye-shaped openings have been developed, taking into consideration the influence of the changes in degree of shear connections. The assessment based on stress amplitude for risk of fatigue failure under low cycle service load is presented as design guides in this paper. It is concluded that the risk grows along with the increase of composite actions in beams.

Analysis of plain-weave composites

The paper analyzes the mechanical properties of plain-weave composites by employing different micromechanical models. Their in-plane and flexural properties are estimated using analytical approaches, including the rule of mixtures and one-dimensional composite beam and two-dimensional mosaic models. The expressions of effective material properties are obtained for one-, two-, and three-ply woven composites. The results obtained are in agreement with published data.

Numerical Modelling of Shear Connection in Steel-Concrete Composite Beams with Trapezoidal Slabs

This paper presents a review of the numerical analysis of composite steel-concrete beams, with particular attention on the modelling of composite beams containing deep trapezoidal slabs cast onto profiled steel sheeting. It is concluded that while robust algorithms are available, there is considerable scope for improvement of these models as an alternative to undertaking expensive testing programs in order to formulate practical design procedures. This is of particular relevance to Australian practice, as timely revisions of its composite structures standard are needed.

Optimal Design of Adaptive Laminated Beam Using Layerwise Finite Element

First, an efficient and accurate finite element model for smart composite beams is presented. The developed model is based on layerwise theory and includes the electromechanical coupling effects. Then, an efficient design optimization algorithm is developed which combines the layerwise finite element analysis model for the smart laminated beam, sensitivity analysis based on analytical gradients and sequential quadratic programming (SQP). Optimal size/location of sensors/actuators is determined for dynamic displacement measurement purposes and for vibration control applications. For static and eigenvalue problems, the objective is to minimize the mass of the beam under various constraints including interlaminar stresses, displacements, and frequencies. For transient vibration problems, the objective is the minimization of the actuation control effort to suppress the vibration in a controlled manner. Illustrative examples are provided to validate the formulation and to demonstrate the capabilities of the present methodology.

Three-Dimensional FE Modelling of Simply-Supported and Continuous Composite Steel-Concrete Beams

Composite steel-concrete beams represent an economic form of construction used in both building and bridge applications. The composite action is usually provided by the presence of shear connectors welded to the top of the steel joist and embedded in the concrete slab. The flexural response is strongly dependent on the rigidity provided by these connectors. Initial studies in this area highlighted that their deformability needs to be evaluated and included in the modeling for an accurate structural representation. For this purpose, different types of push-out tests have been proposed to date to describe the load-slip relationships of shear connectors. These relationships are usually used in numerical simulations when modeling experimental tests or performing parametric studies. In this context, the finite element model proposed in this paper intends to provide a representation of the composite behaviour of floor beams without the need to rely on constitutive relationships obtained from push-out tests. The model is validated against experimental results available in the open literature carried out using simply-supported and continuous static configurations and based on composite beams with solid and composite slabs.

Advanced Finite Element Modelling of Composite Beams with High Strength Materials and Deformable Shear Connectors

This paper presents a comprehensive numerical investigation into the structural behaviour of simply supported composite beams with high strength materials and deformable shear connectors. Advanced two and three dimensional finite element models of the simply supported composite beams are established, and they have been carefully calibrated against the results of two test beams reported in the literature. The two dimensional finite element models are then extended to investigate the structural behaviour of simply supported composite beams with different combinations of high strength steels and concrete. A number of key findings of the numerical investigation are presented after careful consideration on the predicted moment capacities of the composite beams determined from various methods. It is shown that an elasto-plastic stress distribution should be adopted to determine the moment capacities of composite beams using a wide range of steel and concrete materials with high structural adequacy.

Modelagem numérica de vigas mistas aço-concreto

A utilização de estruturas mistas está cada vez mais presente nas obras de Engenharia Civil. As vigas mistas, em particular, são estruturas compostas por dois materiais, um perfil metálico, situado em região predominantemente tracionada, e uma seção de concreto, situada em região predominantemente comprimida, ligados entre si através de dispositivos metálicos denominados de conectores de cisalhamento. As funções prin- cipais dos conectores são: permitir o trabalho solidário da laje-viga, restringir o escorregamento longitudinal e o deslocamento vertical na interface dos elementos e, absorver forças de cisalhamento. Nesse contexto, apresentam-se neste trabalho, modelos numéricos tridimensionais de vigas mistas aço-concreto, com a finalidade de simular o seu comportamento estrutural, enfatizando a interface laje-viga. As simulações foram feitas através do software ANSYS versão 10.0, que tem como base o Método de Elementos Finitos. Os resultados obtidos foram comparados com os previstos por norma e com referências encontradas na revisão bibliográfica, verificando-se que a modelagem numérica é uma ferramenta válida para a análise de vigas mistas aço-concreto.

Beam element with spatial variation of material properties for multiphysics analysis of functionally graded materials

In this paper, two different methods for modelling of functionally graded material (FGM) beam with continuous spatially varying material properties will be presented and compared, namely the multilayering method and the direct integration method. Both the methods are related to homogenization of spatially varying material properties of real FGM beam and to calculation of the secondary variables of the FGM beams. The multilayering method is based on the laminate theory, which is very often used by modelling of the multilayer composite beams. The direct integration method transform spatial continuous varying material properties to the effective ones by direct integration of derived homogenization rules. In next part of the paper, new multiphysical beam finite element will be presented, which in conjunction with the proposed homogenization methods can be used for very effective analysis of the FGM beam structures. The numerical experiment will be presented concerning the multiphysical (electro–thermal–structural) analysis of the chosen FGM beams with spatial continuous variation of material properties.

Finite element models for nonlinear analysis of steel–concrete composite beams with partial interaction in combined bending and shear

The study in this paper compares three different beam models and relevant finite elements for the nonlinear analysis of composite members with partial interaction. These models are derived by coupling with a deformable shear connection two Euler–Bernoulli beams (only flexural deformability and flexural failure mode of each beam component), an Euler–Bernoulli beam to a Timoshenko beam (addition of shear deformability and shear failure mode for one component only), two Timoshenko beams (addition of shear deformability and shear failure mode for both components). Simply supported and continuous steel–concrete composite beams for which experimental results are available in the literature are used as benchmark problems. Aspects of the structural behaviour considered include: (i) effects of the shear deformability of the steel and slab components at various load levels; (ii) differences in computed collapse loads; (iii) differences in the internal actions, i.e. axial forces, bending moments, vertical shears and interface shear forces at different levels of loading. A study on the convergence rate of the finite element solution and considerations on locking-free finite elements are also presented. Results show that the three models present small differences when composite beams dominated by the bending behaviour are considered. On the other hand differences are significant for beams in which the interaction between bending and shear plays a substantial role; in these cases neglecting the shear behaviour in the composite beam model leads to considerably inaccurate predictions of the structural behaviour.

A New Type Dynamic Vibration Absorber to Reduce Broad-Band Vibration in Plates

A new type dynamic vibration absorber, which consists of steel layer and variable cross section rubber layer fitted to plate by bolt through L-shape connection, is introduced firstly and applied to control vibration of plates at multi mode frequencies in this paper. The aim of the present paper is to study the energy absorbing ability of the new type dynamic vibration absorber and apply optimization method to obtain parameters of absorber which is excellent in absorbing energy. The coupling model of composite beam and plate is established by power flow method and energy of plate attenuated by absorber is analyzed. To improve energy dissipated by absorber, the particle swarm method is used to optimize parameters of absorber to minimize vibration energy of the plate. An experiment is executed to certificate the energy mitigated by absorber to validate analytical modeling method. The test data are consistent with the analytical results, demonstrating that the new type dynamic vibration absorber can suppress the vibration energy at every mode of plate and achieve a goal of multi-mode control.

On the Compliance and Energy Release Rate of Generically-unified Beam-type Fracture Specimens

A unified approach is proposed to evaluate the compliance and energy release rate (ERR) of generic beam-type interface fracture specimens. Based on a sub-layer Timoshenko beam theory, the classic composite (rigid joint), shear deformable (semi-rigid joint), and interface deformable (flexible joint) bi-layer beam models are revisited, from which the compliance and ERR of the generic beam-type fracture specimens are determined. According to specific combinations of loading conditions and material properties of each sub-layer, the generic fracture specimens are reduced to the conventional fracture specimens for actual applications. The effects of the crack tip deformation on the ERR of the interface crack are compared among the three different joint models, from which the evolving accuracy of the joint models to the ERR predictions of beam-type fracture specimens is manifested. The derived explicit formulas and improved solution for the compliance and ERR of the common beam-type fracture specimens can be effectively used to reduce data in interface fracture experiments and increase accuracy of fracture toughness evaluation of dissimilar material interfaces.

Time-dependent creep and shrinkage analysis of composite beams curved in-plan

This paper develops a numerical formulation for the time-dependent creep and shrinkage analysis of steel–concrete composite beams that are curved in-plan under conditions of service load. The creep behaviour of the concrete is considered by using the viscoelastic Wiechert model, in which the aging effect of the concrete is taken into account. The curved composite beam model that is developed also accounts for the partial shear interaction at the deck-girder interface in the tangential (or longitudinal) direction, as well as in the radial (or horizontal) direction, due to the flexibility of the shear connectors. Models based on the developed formulation are validated by comparisons with sophisticated and computationally intensive ABAQUS shell element models, and with available results reported in the literature. The effects of initial curvature and partial interaction on the time-dependent behaviour of curved composite beams are also illustrated in the examples.

A Finite Element Model for Composite Beams with Piezoelectric Layers using A Sinus Model

AbstractIn this study, finite element modeling of composite beams with distributed piezoelectric sensors and actuators which is based upon a coupled electromechanical model has been considered. For modeling of mechanical displacement through the thickness, a sinus model that satisfies continuity conditions of transverse shear stresses and the boundary conditions on the upper and lower surfaces of the beam has been employed. In the presented model, the number of unknowns is not dependent on the number of layers. The variation of electric potential in each piezoelectric layer has been modeled using layer-wise theory. By applying the virtual work principle (VWP), a formulation has been developed for a twonodded Hermitian-2(n + 1) layer-wise nodded element for a n-layered beam. The VWP leads to a derivation that could include dynamic analysis. However, in this study only static problems have been considered. Comparison of results obtained from this formulation with available works in the literature, demonstrates efficiency of proposed model in analysis of laminated beams under mechanical and electrical loadings.