Abstract
Automated Fiber Placement (AFP) machines can manufacture composite panels with curvilinear fibers. In this article, the critical buckling load of grid-stiffened curvilinear fiber composite panels is maximized using a genetic algorithm. The skin is composed of layers in which the fiber orientation varies along one spatial direction. The design variables are the fiber orientation of the panel for each layer and the stiffener layout. Manufacturing constraints in terms of maximum curvature allowable by the AFP machine are imposed for both skin and stiffener fibers. The effect of manufacturing-induced gaps in the laminates is also incorporated. The finite element method is used to perform the buckling analyses. The panels are subjected to in-plane compressive and shear loads under several boundary conditions. Optimization results show that the percentage difference in the buckling load between curvilinear and straight fiber panels depends on the load case and boundary conditions.
Highlights
The main driver in the development of materials for aerospace structures is weight reduction
This study focuses a methodology to optimize the variable-angle composite panels manufactured via Automated Fiber Placement (AFP)
The results showed that gaps degraded in-plane stiffness and buckling load while overlaps improved them
Summary
The main driver in the development of materials for aerospace structures is weight reduction. Several studies recently investigated the design optimization, manufacturing and testing of variable-fiber angle composite structures considering FW [2,3,4], TFP [5,6] and AFP [7,8,9]. The design space is enlarged and substantial improvements in structural performance or weight savings can be obtained[10] These panels can be employed to manufacture wing or fuselage skins. The stiffness distribution of the panel was influenced by the angle variation and the distance between the stiffeners Kapania and his co-authors (see [20,21,22]) employed NURBS (Non-Uniform Rational B-Splines) to describe the reference path of curvilinear stiffeners. An optimization framework has been developed with the aim of designing composite panels with curvilinear fibers and curvilinear stiffeners for maximum buckling performance.
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