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In this research, the equations governing the vibrations of a composite curved beam reinforced with graphene platelets have been solved using a quasi-3D model of the beam. The investigated composite beam is multi-layered, each layer can be reinforced by different amount of graphene platelets, which leads to a functionally-graded distribution of reinforcements. According to the quasi-three-dimensional theory of beams, the effect of thickness stretching and shear strains is included and does not require a shear correction factor. It should be noted that according to the geometry of the assumed beam, deformations and strains are considered small and the structural relations of the material are linear. The governing equations of the curved beam are derived based on Hamilton’s principle after calculating the kinetic and strain energies. The boundary conditions of the beam are assumed to be simply supported on both ends. Therefore, the displacement parameters of the problem have been explained with Navier’s solution method and with the use of Fourier expansions, closed form expressions are obtained as elements of mass and stiffness matrices. The elasticity modulus of the beam is rewritten using the Halpin–Tsai model and Poisson’s ratio and mass density using the rule of mixtures. Finally, the results of each section are presented in the form of tables. First, the results of this research were verified with the existing results, and then new results were introduced to investigate the effective parameters of the problem. These results include the investigation of the distribution of graphene platelets, the effect of the weight percentage of the filler and the geometric properties of the beam. The results of this research on the dynamic response of the beam show that the effects of increasing the volume percentage of graphene, even to a small extent, can be seen in increasing the natural frequency of the curved beam.

This paper presents the elastic strain energy, the potential energy with the second order terms of finite rotations, and the kinetic energy with rotary inertia effect for thin-walled composite beams of mono-symmetric cross-section. The equations of motion and force-displacement relationships are derived from the energy principle and explicit expressions for displacement parameters are given based on power series expansions of displacement components. The exact dynamic stiffness matrix is determined using the force-displacement relationships. In addition, the finite element model based on Hermitian interpolation polynomial is developed. In order to verify the accuracy and validity of the formulation, numerical examples are solved and the solutions are compared with results from ABAQUS's shell elements, analytical solutions from previous researchers and the finite element solutions using the Hermitian beam elements. The influence of constant and linearly variable axial forces, fiber orientation, and boundary conditions on the vibration behavior of composite beam are also investigated.

In this paper, a comparative study is performed for a symmetrically laminated composite cantilever beam with and without a tip mass under harmonic base excitation. The base is subjected to both flapwise and chordwise excitations tuned to the primary resonances of the two directions and conditions of 2:1 autoparametric resonance. In the literature, the governing nonlinear equations of the same problem without tip mass have been derived using the extended Hamilton's principle. Extension is made in this study to include the effect of a tip mass on the response of the beam. The natural frequencies are obtained numerically using the diversity guided evolutionary algorithm (DGEA). Next, the multiple scales method is applied to determine the nonlinear response and stability of the system. A set of four first-order differential equations describing the modulation of the amplitudes and phases of interacting modes are derived for the perturbation analysis. For verification, the above equations are reduced to the special case of the cantilever beam without tip mass for comparison with existing results. Finally, the effect of the tip mass on the stability of the fixed points and on the amplitude of oscillation about the equilibrium points in both the frequency and force modulation responses is examined.

A new derivation of Euler's Elastica with transverse shear effects included is presented. The elastic potential energy of bending and transverse shear is set up. The work of the axial compression force is determined. The equation of equilibrium is derived using the variation of the total potential. Using substitution of variables an exact solution is derived. The equation is transcendental and does not have a closed form solution. It is evaluated in a dimensionless form by using a numerical procedure. Finally, numerical examples of laminates made of composite material (fiber reinforced) and sandwich panels are provided.

In this paper, the effectiveness of a saturation control strategy in suppressing vibration of a rotating composite thin walled beam is studied. The mathematical model of the flexible beam takes into account a shear deformation effect, a warping function, a centrifugal force and the Coriolis acceleration. To extend the generality of the proposed formulation an inertia of the hub is also considered. Adaptive capability of the beam is achieved through the implementation of the saturation control algorithm.

Within the performed tests, the discussed control strategy is applied for different magnitudes of flexural–torsional vibration modes resulting from different orientations of beam laminate-reinforcing fiber’s. The obtained results prove the applied nonlinear control to be the effective method for beam vibration suppression in near-by resonance zones for all studied cases. Parametric studies considered different rotating speeds of the system. It is shown that the vibration of the beam can be suppressed to similar levels independently of the transportation motion rotating speed. However, significant differences in the width of vibration suppression zones are observed.

The influence of nonuniform heating on the critical buckling temperature of laminated glass-epoxy composite beam has been investigated experimentally with the help of a novel experimental setup. The beam is numerically investigated using nonlinear finite element analysis. An initial geometric imperfection is introduced to the modeled geometry in numerical technique to have an experimental–numerical comparison of temperature-deflection plot. The results indicate that the critical buckling temperature of a uniformly heated beam has a significant difference in comparison to the nonuniformly heated beam and it depends on the heating source location and the resulting temperature distribution along the length direction of the beam.

This study focuses on developing and implementing Mamdani hybrid fuzzy logic inference system (FIS) for transverse crack detection and fault diagnosis in a woven fiber laminated glass/epoxy composite beam using different vibration modes of natural frequencies. The shifting of vibration is attributed to the implication of cracks. These vibration signatures are fuzzified through hybrid fuzzy sets (triangular, trapezoidal, Gaussian) and scaled to crack location and depth using the fuzzy rules and defuzzification process. The vibration signatures are recorded using ABAQUS finite element (FE) simulation software for a fixed beam and are fed as input parameters to the developed FIS for computing the desired outputs. The realization for crack depth and position is experimentally verified through a Fast Fourier Transform (FFT) analyzer. The experimental results with simulated data show that fuzzy logic application detects crack positions and depth accurately at different levels. It is concluded that the hybrid FIS bears a close resemblance to the experimental analysis and also stands out as an effective method for crack detection in LCB over other standalone methods. The current method can be used as a cost-effective non-destructive technique for health monitoring and fault diagnosis of composite beam structures in any practical field.

We present a high fidelity numerical simulation technique to analyze the nonlinear behavior of a composite beam under cyclic loading. The analysis is performed by using the in-house software called E-Simulator. A constitutive model for concrete; extended Drucker–Prager model considering the compressive failure and the tensile crack has been employed and the parameters are identified so that compressive and tensile behavior of concrete can be reproduced. The relation between the bending moment and deflection angle of a composite beam has been analyzed and compared with experimental results. Damage propagation and stiffness degradation results of concrete slab are demonstrated.

The composite steel–concrete rigid frame bridge is composed of steel or composite girders connecting rigidly to RC piers, and has advantages of lower maintenance costs, faster construction, and higher resistance and ductility during an earthquake. In this paper, a new type of steel–concrete composite rigid connection is developed and studied by finite element analysis. The comparison with other types of connections shows that this new type of connection has a good structural performance from the confining of concrete by steel and preventing the buckling of steel by concrete.

Shear connector is a part of steel-concrete composite beam, and it is the key to ensure the whole performance of composite beam. This paper presents the effects of flange and web thickness, height and width of angle shear connectors by using experimental and FE Analysis. 6 push-out tests were carried out to verify the correctness of FE models. In this experiment, the failure mode was the concrete crushing splitting with the angle steels yielded at the junction of web and flange. Specimens had a plastic behavior before failure. As the angle shear connectors concentrate the applied load on the root of flange, the thickness and width of flange and web are the main factors that influence the ultimate strength of angle shear connectors. The height of flange and web could hardly affect the ultimate strength.