Abstract:

ESDU 94006 introduces a Fortran program, ESDUpac A9406, for calculating the buckling loading of composite plates for which in both the direct and flexural stiffness matrices the first two terms in the last column and last row are zero and in the coupling stiffness matrix the first two terms of the first two rows and the last term of the third row are zero. Such stiffness matrices arise when the fibres are all laid to make the same angle with a plate edge, but the angles are of opposite signs in each pair of laminae equidistant from the centre plane. The plate is assumed to be initially flat and rectangular, with loading applied uniformly along the edges. No account is taken of through-the-thickness shear deformation. Uniaxial or biaxial loading (in which one load can be tensile) is treated; under biaxial loading either one load may be fixed, and the other at buckling determined, or the ratio of the loads may be fixed, and the loads in that ratio at buckling found. Example curves illustrate the variation of the buckling load with plate aspect ratio showing the influence of the coupling stiffness matrix. The full input and output to the program is explained and illustrated with worked examples.