Preliminary design of an amphibious aircraft by the multidisciplinary design optimization approach

In the past few decades, besides the important progress that the aeronautical and aerospace engineering have achieved, the requirement of improving aircrafts performances and features, and the need of devising crafts performing special missions were growing meanwhile. Nevertheless, developing unconventional or innovative configurations the reference data extrapolated by known standard configurations are useless. Thus, the concept of Multidisciplinary Design Optimization, MDO, for the preliminary design of aeronautical and aerospace structures is the natural answer to the challenge that aeronautical and aerospace structures represent especially if new configurations of crafts are requested. Hence, the aim of this paper is to present an MDO procedure and an associated overview of the work code called MAGIC, (Multidisciplinary Aircraft desiGn of Innovative Configurations), for conceptual design of non-conventional aircraft configurations in civil aviation. Accordingly, the relevance of an adequate modeling is an essential issue in order to obtain meaningful designing results. Thus, the intimate link between MDO, modeling, and simulations fields is evident. The algorithms used in MAGIC for modeling structures, aerodynamics, and aeroelasticity are first-principles based, since for innovative configurations the designer cannot rely upon past experience. In addition, we emphasize the conceptual design: thus, the algorithms used must be accurate and efficient, so as to produce accurate predictions with a relatively small computational effort. In the paper presented the structural analysis (statics -including the buckling analysis- and dynamics) has been performed using an external commercial FEM code. Furthermore, since the special condition of ground effect flight is considered, we have adopted the specific methodology introduced by Keldysh-Lavrentiev (KL) and available in the steady aerodynamic case for airfoils in bounded domain in order to evaluate the aerodynamic loads. The efficiency of the proposed methodology is illustrated by applications to specific configurations.