A geometry centered process in airframe design

The requirement for different abstractions of the core geometry is a key challenge in development of future design systems. In particular the fidelity of the analysis models tends to increase as more knowledge of the design is gained, but these higher fidelity models must coexist alongside coarser models and information must pass consistently and reliably between them. For example a detailed 3D solid of a joint may be embedded within a beam-shell model which ultimately obtains its loads from an aerodynamic model of the cross-section. Much of the difficulty for analysis model derivation arises due to the complexity of the master solid geometry. Shapes and configurations need to be identified, and abstracted to a suitable analysis form. An aerodynamic model may require only the exterior profile of the aircraft, but the structural model may require that stiffeners be represented as a line at the neutral axis with associated cross-sectional properties, or the skin is reduced to a 2D surface. The approach presented here is to remove the geometry as the reference source and replace it with a more abstract representation of the aircraft, and thereafter to use a common geometry generation process for the various disciplines. Model creation then becomes the central focus of the design process for all the disciplines being integrated. This then becomes an implicit part of the systems engineering process. The solid geometry, analysis, manufacturing and economic models can then be derived as required from a common design representation ensuring consistency, ease of use and reliability.