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

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 filament steering angle. Particle swarm optimization coupled with three Kriging-based metamodels is used 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 of 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 while buckling-resistant designs are reached, along with non-conventional optimum layouts thanks to the high degree of thickness build-up tailoring.

Automated summary

In this study, variable-angle filament-wound (VAFW) cylinders were optimized for minimum mass under manufacturing constraints and various design loads using particle swarm optimization and Kriging-based metamodels. The nonlinear relationship between the tow winding angle and thickness in VAFW structures was explored using a design parameterization based on a second-order polynomial variation. A Bogner-Fox-Schmit-Castro finite element was used to accurately represent the variable stiffness properties of the shells. The analysis of the design space using metamodels revealed a gap in the buckling strength, which was confirmed through genetic algorithm optimizations. Extreme lightweight and buckling-resistant designs were achieved along with non-conventional optimum layouts thanks to the tailored thickness buildup.