B EFFECT OF BOUNDARY CONDITIONS ON BUCKLING LOAD FOR LAMINATED COMPOSITE DECKS PLATES

Abstract

Finite element (FE) method is presented for the analysis of thin rectangular laminated
composite decks plates under the biaxial action of in – plane compressive loading. The
analysis uses the classical laminated plate theory (CLPT) which does not account for shear
deformations. In this theory it is assumed that the laminate is in a state of plane stress, the
individual lamina is linearly elastic, and there is perfect bonding between layers. The classical
laminated plate theory (CLPT), which is an extension of the classical plate theory (CPT)
assumes that normal to the mid – surface before deformation remains straight and normal to
the mid – surface after deformation. Therefore, this theory is only adequate for buckling
analysis of thin laminates. A Fortran program has been developed. New numerical results are
generated for in – plane compressive biaxial buckling which serve to quantify the effect of
boundary conditions on buckling loading. It is observed that, for all cases the buckling load
increases with the mode number but at different rates depending on whether the plate is simply
supported, clamped or clamped – simply supported. The buckling load is a minimum when
the plate is simply supported and a maximum when the plate is clamped. Because of the
rigidity of clamped boundary condition, the buckling load is higher than in simply supported
boundary condition. It is also observed that as the mode number increases, the plate needs
additional supp