OPTIMIZATION OF SYMMETRICAL LAMINATES WITH INTERNAL LINE SUPPORTS FORMAXIMUM BUCKLING LOAD

Finite element solutions are presented for the optimal design of symme trically laminated rectangular plates with various types of internal l ine supports. These plates are subject to a combination of simply supp orted, clamped and free boundary conditions. The design objective is t he maximisation of the biaxial buckling load. This is achieved by dete rmining the fibre orientations optimally with the effects of bending-t wisting coupling taken into account. The finite element method coupled with an optimisation routine is employed in analysing and optimising the laminated plate designs. The effect of internal line support type and boundary conditions on the optimal ply angles and the buckling loa d are numerically studied. The laminate behavior with respect to fibre orientation changes significantly in the presence of internal line su pports as compared to that of a laminate where there is no internal su pporting. This change in behavior has significant implications for des ign optimisation as the optimal values of design variables with or wit hout internal supporting differ substantially.