Lightweight design of variable-angle filament-wound cylinders combining Kriging-based metamodels with particle swarm optimization

Abstract

Variable-angle filament-wound (VAFW) cylinders are herein optimized for minimum mass under manufacturing constraints, and for various design loads. A design parameterization based on a second-order polynomial variation of the tow winding angle along the axial direction of the cylinders is utilized to explore the nonlinear steering-thickness dependency in VAFW structures, whereby the thickness becomes a function of the fiber angle. Particle swarm optimization coupled with several Kriging-based metamodels is developed to find the optimum designs. A single-curvature Bogner-Fox-Schmit-Castro finite element is formulated to accurately and efficiently represent the variable stiffness properties of the shells, and verifications are performed using a general-purpose plate element. Alongside the main optimization studies, a vast analysis on the design space is performed using the metamodels, showing a gap in the design space for the buckling strength that is confirmed by genetic algorithm optimizations. Extreme lightweight whilst buckling resistant designs are found, along with non-conventional optimum layouts thanks to the high degree of thickness build-up tailoring.