Buckling Optimization of Variable Stiffness Composite Panels for Curvilinear Fibers and Grid Stiffeners

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.

Simultaneous Layout, Sizing and Topology Optimization of Stiffened Panels using CAD-based Parameterization

“…For additional mass saving, it is important to perform simultaneous optimization of size, layout, and topology variables. Therefore, various studies on this area of research were conducted in the last decade [3]- [7]. In these studies, a gradient-free optimizer was used which usually requires a higher number of evaluations when compared to a gradientbased optimizer.…”

“…PhD Student, Aerospace Structures and Materials, Email: h.rahman@tudelft.nl 2 Associate Professor, Aerospace Structures and Materials, AIAA Associate member 3. Assistant Professor, Aerospace Structures and Materials.…”

Fundamental Frequency Optimization of Variable Angle Tow Laminates with Embedded Gap Defects

“…In this way, it is not required such a refined mesh and computational cost is saved. Several authors considered this modeling methodology to include the effect of both gaps and overlaps [19][20][21]. Marouene et al [19] study considered this last methodology to model variable stiffness plates with the goal of maximizing the in-plane stiffness and the buckling load.…”