Author(s): Misirlis K, Downes J, Dow RS
Abstract: A numerical investigation on the effects from initial imperfection shapes on the strength of long, fibre-reinforced, composite panels is presented in this paper. Fourteen alternative initial geometric imperfections are imposed in long plates for two alternative lay-up configurations; a tri-axial and a balanced, woven roving configuration. The sectional response is investigated with nonlinear finite element analysis which incorporates a progressive failure model for the degradation of the material properties. For the analysis both thick and thin panels are considered with breadth to thickness ratios of 10 and 50 respectively. The comparison focuses on the effects on stiffness and ultimate strength of the panels and uses as a basis the preferred buckling mode imperfection for each lay-up configuration. Results demonstrate a conservative approach when adopting the preferred buckling mode shape for overall initial imperfections and a significant reduction on performance from localised imperfections.