Sequential use of conceptual MDO and panel sizing methods for aircraft wing design

The optimisation results for composite and metallic versions of a regional aircraft wing are compared using the multidisciplinary optimisation (MDO) program CALFUNOPT. The program has been developed for the conceptual design stage and models the wing using just 11 beam elements. The wing has been optimised for three combinations of the following constraint cases: static strength; aeroelastic roll efficiency (represented by limiting the twist of the wing for an aileran loading) and aeroelastic divergence. As expected. comparison shows that the composite wing designs are significantly lighter than the metallic ones, due to the well-known tailoring of the composite material. However, the simple model reveals some insight that may be useful to the designer, and which could be lost within a more derailed finite element approach. The upper-skin compression panels produced by the conceptual MDO program, for both versions of the wing, have then been optimised using the: more detailed and accurate panel sizing tool VICONOPT, which takes buckling into account. Such optimisation increases the panel mass by 5-10% and also provides a suitable ratio of stiffener to sr;in area for use in the conceptual MDO model.