Buckling-optimized variable stiffness laminates for a composite fuselage window section

Abstract

Composite material offers potential compared to metals in the way the final structure can be tailored with the anisotropic material properties. In most thin planar structures in aerospace today these anisotropic properties of composite material are not fully exploited because traditional quasi isotropic laminates are used. Modern Automated Fiber Placement manufacturing capabilities enable the introduction of variable stiffness laminates on a larger scale. In this paper a two-step variable stiffness design approach is proposed. First the optimal fiber orientations are determined. From these fiber orientations the physical composite fiber tows are derived. Besides buckling optimization, as addressed in this paper, variable stiffness laminates can also be used e.g. for improvement of load transfer and morphing structures.