Flexural–torsional buckling of thin-walled composite box beams

Abstract

Buckling of an axially loaded thin-walled laminated composite is studied. A general analytical model applicable to the flexural, torsional and flexural-torsional buckling of a thin-walled composite box beam subjected to axial load is developed. This model is based on the classical lamination theory, and accounts for the coupling of flexural and torsional modes for arbitrary laminate stacking sequence configuration, i.e. unsymmetric as well as symmetric, and various boundary conditions. A displacement-based one-dimensional finite element model is developed to predict critical loads and corresponding buckling modes for a thin-walled composite bar. Governing buckling equations are derived from the principle of the stationary value of total potential energy. Numerical results are obtained for axially loaded thin-walled composites addressing the effects of fiber angle, anisotropy, and boundary conditions on the critical buckling loads and mode shapes of the composites.

Interaction curves for vibration and buckling of thin-walled composite box beams under axial loads and end moments

“…Effect of axial force on the critical buckling moments is shown in Table 1. The critical buckling loads (P cr ) and the critical buckling moments (M cr ) without axial force agree completely with those of previous papers [24,25]. In Table 2, with the presence of bending moment, the lowest three natural frequencies with and without the effect of axial force by the finite element analysis are compared to those by the orthotropy solution, which neglects the coupling effect of E 25 from Eqs.(36a)-(36c).…”

“…In this paper, which is an extension of the authors' previous works [24][25][26], flexural-torsional coupled vibration and buckling of thin-walled composite box beams with arbitrary lay-ups under constant axial loads and equal end moments is presented. This model is based on the classical lamination theory, and accounts for all the structural coupling coming from the material anisotropy.…”

“…By substituting Eqs. (10) and (25) into Eq. (26), the explicit form of governing equations of motion can be expressed with respect to the laminate stiffnesses E ij as…”

Flexural-torsional coupled vibration of anisotropic thin-walled beams with biconvex cross-section

“…In the light of these pioneering and rigorous studies, detailed investigations of thin-walled composite beams have also been reported focusing on the free vibration [6][7][8][9], stability and control [10,11] and aeroelasticity [12][13][14][15] analyses. However, the field of thin-walled composite beams accommodate a number of theoretical issues due to various non-classical effects which are inherently present in this kind of structures.…”

An analytical model for deformation analysis of wind turbine adaptive blades

“…Kim and Shin [6] provided exact solutions for twist angle and fibre stresses of thin-walled box beams considering the effects of elastic couplings and restrained warping. Lee and Lee [7], Vo and Lee [8,9] also developed two analytical models for beams under torsional loading based on strain energy method. Librescu and Song [10,11] published a set of theories for thin-walled composite beams applicable to deformation and vibration problems.…”