NONLINEAR FINITE-ELEMENT MODELING OF AN INTEGRALLY STIFFENED COMPOSITE PANEL

The progressive introduction of advanced fibre composite materials int o aerospace structures has enabled significant performance improvement s to be achieved. Structures using these materials are generally desig ned so that their behaviour is essentially linearly elastic through to failure. The realisation of further significant weight reductions in light-weight aerospace structures is highly dependent on design techno logies which will enable postbuckling stiffened panels to be utilised in primary structures. The capabilities of the finite element code, MS C/NASTRAN, to predict the onset of buckling and subsequent postbucklin g behaviour of a blade-stiffened fibre composite panel have been inves tigated. The panel consists of T300/914 carbon/epoxy unidirectional ta pe and is reinforced by integral stiffeners. Basic modelling technique s for the efficient analysis of such postbuckling assemblies are prese nted. It is concluded that the prediction of their performance require s specialist modelling skills and a sound understanding of the behavio ur of the composite materials used in the structure.