BUCKLING OF UNSYMMETRICAL, CROSS-PLY LAMINATES WITH MATRIX CRACKS

The effect of matrix cracks on the buckling of unsymmetrical, cross-ply laminates is investigated. The cracks are modelled as aligned slit cracks across the ply thickness and transverse to the laminate plane. The distribution of cracks is assumed to be statistically homogeneous corresponding to an average crack density. The results are given for antisymmetrically- and unsymmetrically-laminated plates with a given density of matrix cracks. The effect of reduction in the laminate stiffness is studied by plotting the ratio of the buckling loads of cracked and uncracked laminates against the aspect ratio, crack density and relative layer thicknesses. It is observed that the amount of reduction in the buckling load depends on the stacking sequence as well as on the relative thicknesses of layers. This reduction is found to be substantially less than the reduction in the affected elastic moduli of the material.