Buckling Of Composite Beams Research Articles

Linear Elastic Lateral Buckling (Including Shear Deformation) and Linear Elastic Lateral Torsional Buckling of Composite Beams - an Analytical Engineering Approach

Linear Elastic Lateral Buckling (Including Shear Deformation) and Linear Elastic Lateral Torsional Buckling of Composite Beams - an Analytical Engineering Approach

Analytical Solutions for Free Vibration and Buckling of Composite Beams Using a Higher Order Beam Theory

To satisfy the interfacial shear force continuity conditions, a new model is proposed for the two-layer composite beam with partial interaction by modifying Reddy's higher order beam theory. The governing differential equations for free vibration and buckling are formulated using the Hamilton's principle, the natural frequencies and axial forces are thus analytically obtained by Laplace transform technique. The analytical results are verified through the comparison with those of several other models common in use; and the presented model is found to be a finer one than the Reddy's. A parametric study is also performed to investigate the effects of geometry and material parameters.

Application of the VIM to thermal buckling of composite beams on an elastic foundation

AbstractIn this paper, thermal buckling analysis of composite laminated beams resting on a two-parameter elastic foundation is carried out by means of the variational iteration method (VIM). The solution procedure is based on the first-order shear deformation beam theory of Timoshenko combined with the von Karman type of geometrical non-linearity. Both edges of the beam are assumed to be axially restrained while may possess various out-of-plane boundary conditions. The elastic foundation is modelled via the two-parameter Pasternak medium which takes into account the vertical interaction of the elements. The governing equilibrium equations are obtained by means of the virtual displacement principle. Stability equations are then obtained by means of the adjacent equilibrium criterion. These equations are uncoupled to extract individual equations in terms of lateral displacement. The resulted differential equations are solved via the VIM. The study examines the VIM in obtaining the closed-form analytical solutions for thermal buckling of composite laminated beams. Furthermore, it is shown that for some special materials with negative thermal expansion coefficient, buckling may occur under cooling rather than heating or it may not occur at all.

Axial-flexural coupled vibration and buckling of composite beams using sinusoidal shear deformation theory

A finite element model based on sinusoidal shear deformation theory is developed to study vibration and buckling analysis of composite beams with arbitrary lay-ups. This theory satisfies the zero traction boundary conditions on the top and bottom surfaces of beam without using shear correction factors. Besides, it has strong similarity with Euler–Bernoulli beam theory in some aspects such as governing equations, boundary conditions, and stress resultant expressions. By using Hamilton’s principle, governing equations of motion are derived. A displacement-based one-dimensional finite element model is developed to solve the problem. Numerical results for cross-ply and angle-ply composite beams are obtained as special cases and are compared with other solutions available in the literature. A variety of parametric studies are conducted to demonstrate the effect of fiber orientation and modulus ratio on the natural frequencies, critical buckling loads, and load-frequency curves as well as corresponding mode shapes of composite beams.

Vibration and buckling of composite beams using refined shear deformation theory

Vibration and buckling analysis of composite beams with arbitrary lay-ups using refined shear deformation theory is presented. The theory accounts for the parabolical variation of shear strains through the depth of beam. Three governing equations of motion are derived from Hamilton's principle. The resulting coupling is referred to as triply coupled vibration and buckling. A two-noded C1 beam element with five degree-of-freedom per node which accounts for shear deformation effects and all coupling coming from the material anisotropy is developed to solve the problem. Numerical results are obtained for composite beams to investigate effects of fibre orientation and modulus ratio on the natural frequencies, critical buckling loads and corresponding mode shapes.

Thermoelastic restrained buckling of composite beams

A model is developed for the thermoelastic restrained distortional buckling (RDB) of a steel joist in a composite beam in a steel-framed building that may take place during a compartment fire. The overall or member buckling mode must necessarily involve cross-sectional distortion, since the rigid concrete slab in the composite beam prevents the top flange of the steel joist from freely translating, rotating and twisting as would occur in conventional flexural-torsional buckling. The solution is based on a stiffness approach, with the buckling deformations being represented by a Fourier series and the Ritz method being invoked to determine an eigensolution for the critical temperature. High levels of axial restraint provided by cooler frame members can produce significant thermally induced pre-buckling compression, which can lead to early thermoelastic buckling. This significant axial force can lead to potential failure of the connections at the ends of the member, and premature buckling is advantageous as it can relieve the development of this large compressive action. The numerical solution is used to investigate the influence of the parameters affecting RDB of a composite beam in a fire.

Free vibration and buckling of composite beams with interlayer slip by two-dimensional theory

The free vibration and buckling of partial interaction composite beams are investigated using the state-space method based on the two-dimensional theory of elasticity. The analytical solutions of a beam with two simply supported ends are obtained as well as semi-analytical solutions are obtained for other end conditions using the differential quadrature method coupled with the state-space method. The frequencies and buckling loads are tabulated and compared with those available in the literature. Because the plane section assumption of the classical beam theory is not used, the presented method is applicable not only to slender beams, but also to thick beams. Consequently, the presented method can be a benchmark for other approximate methods based on one-dimensional beam theories.

Lateral torsional buckling of composite beams

Lateral torsional buckling of composite beams

Vibration and Buckling of Composite Beams

Abstract The eigenvalue problem corresponding to the vibration and buckling of a composite beam under the action of a conservative axial force is considered. The material properties of the beam or its cross-sectional dimension may vary continuously or discontinuously along its length. The eigen-frequencies and the buckling load are estimated by means of the method of the new quotient which has been recently proposed by Nemat-Nasser, and the results are compared with those obtained by means of the usual Rayleigh quotient and its dual. A scheme of improving the test functions is also presented. This gives very accurate lower and upper bounds for the vibration frequencies, as well as for the buckling load. Results are illustrated by means of several numerical examples which include both the determinate and the indeterminate cases. These examples tend to suggest that the new quotient gives very accurate estimates for this class of problems.