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...

Design, modeling, optimization, manufacturing and testing of variable-angle filament-wound cylinders

This work demonstrates the potential of manufacturing variable-angle composite cylinders via filament winding (FW), called VAFW. The proposed design strategy allows different filament angles along the axial direction by dividing the cylinder into regions of constant angle called frames. Designs using two, four, or eight frames are herein...

Overlap-stiffened panels for optimized buckling performance under minimum steering radius constraints

Recent research on variable stiffness laminates have shown both numerically and experimentally that further improvement on the buckling performance is possible by incorporating overlaps that result in variable thickness profiles. We present the concept of overlap-stiffened designs that take advantage of the non-linear coupling between the tow...

Static test of a variable stiffness thermoplastic composite wingbox under shear, bending and torsion

Automated manufacturing of thermoplastic composites has found increased interest in aerospace applications over the past three decades because of its great potential in low-cost, high rate, repeatable production of high performance composite structures. Experimental validation is a key element in the development of structures made using this...

Buckling and free vibration study of variable and constant-stiffness cylindrical shells

The ability to steer carbon fibre tapes, varying the tow angle, can widen the designs possibilities of cylindrical shells that are one of the main components of aerospace structures. This research presents experimental and numerical investigation of two carbon fibre reinforced plastic cylindrical shells – a cylinder with conventional layup made...

ES-PIM applied to buckling of variable angle tow laminates

The increasing need for automatic mesh generation has led to the development of efficient triangulation algorithms that are able to discretize any 2D or 3D domain. Modern finite element formulations based on strain smoothing techniques (SFEM) provide enhanced convergence properties, preventing yet the stiffening behavior of triangular meshes....

Optimal Design of Variable Stiffness Composite Structures using Lamination Parameters

Fiber reinforced composite materials have gained widespread acceptance for a multitude of applications in the aerospace, automotive, maritime and wind-energy industries. Automated fiber placement technologies have developed rapidly over the past two decades, driven primarily by a need to reduce manufacturing costs and improve product consistency...

Thermal and structural performance of tow-placed, variable stiffness panels

The structural response of two variable stiffness composite panels under thermal and mechanical loads are characterized using experiments and analyses. These panels are advanced composite structures where the fiber angle varies continuously within each ply, and are manufactured using an advanced tow placement system. Both variable stiffness...