Aeroelastic tailoring of composite wing structures by laminate layup optimization

P REVIOUS research showed that elastic coupling and warping restraint might have a positive effect on aeroelastic stability of forward-swept composite wings [1–4]. The work encouraged subsequent investigation into the optimization of composite wing structures for desirable aeroelastic behavior [5–8]. The research has demonstrated that a significant increase of flutter speed can be achieved by optimizing the wing skin thickness or the laminate layups considering the effect of bending–torsion coupling [7,8]. However, the impact of wing geometry upon the influence of stiffness coupling on the aeroelastic optimization has received little attention. This current research is therefore aimed at investigating the effect of swept angle, taper ratio, andmass distribution on aeroelastic tailoring of a composite wing. Six aeroelastic tailoring cases of a composite wing by optimizing the wing box laminate layups have been considered. A classical gradient-based deterministic GD optimization method and a genetic algorithm GA have been employed for comparison purposes. It was noted that the optimized layup solution by using the GD method largely depends on the setting of initial design variables. Nevertheless, this method is efficient and normally produces an optimal result at each step of the optimization process before converging to the final optimal solution. Comparing with the GD method, the GA approach is more robust and produces optimal solutions with little influence from the initial layup despite the need for much more computational time. The example considered in this paper has shown that optimized layups resulting in a maximum increase of flutter speed can be achieved by employing either the GD or GA method. However, wing geometry and mass distribution have significant influence on aeroelastic tailoring results.