The influence of bend-twist coupling on the shear buckling response of thin laminated composite plates

The finite strip method of analysis has been used in this paper to examine the effect of bend-twist coupling on the shear buckling behaviour of lamina ted composite constructions. The distorted nodal lines of the shear bucklin g mode and its complex deformation state in general are readily accounted f or in the analysis procedure through the multi-term nature of the finite st rip buckling displacement field and the appropriate level of structural mod elling. The degree of bend-twist coupling in the laminated composite plates is varied by changing the level of anisotropy in the plies and by altering the lay-up configuration of the plies in the laminated stack. Symmetric la minates of a balanced and unbalanced nature are given consideration. It is shown that, for a given degree of anisotropy in the plies of a laminate and for a given laminate thickness, the stacking sequence of the plies signifi cantly alters the degree of bend-twist coupling. The shear buckling perform ance of composite plates having the same dimensions and being made from the same material are therefore shown in the paper to be quite different. The preclusion of the bend-twist coupling coefficients in the solution procedur e of the finite strip method allows the sheer buckling orthotropic solution to be determined. Comparisons between the coupled and orthotropic solution s are shown in the paper to be markedly different. (C) 1999 Elsevier Scienc e Ltd. All rights reserved.