3616. Methodology For Lightweight Design Of Stiffened Skin In Advanced Aerospace Structures

Paper

Abstract

With increased interest in paradigm-shifting aerospace vehicles, such as those with a blended wing-body configuration or mostly composite structures, it is necessary to develop structural design methods that will help these concepts reach their full potential. Many traditional design methods are only suited for traditional aerospace structures. With the introduction of advanced vehicle geometry and materials, the dimensionality of design problems for advanced structures becomes quite cumbersome. The presented methodology uses a reformulation of the typical mass minimization problem to limit the number of design variables in the design of a stiffened skin panel. Typically, the mass minimization problem definition for structural design is a function of the physical dimensions of the stiffened panels. In the new minimization problem discussed here, the equivalent smeared stiffness terms of the panels become the design variables. For a finite element model with a fixed number of elements, this reformulation provides a consistent number of design variables regardless of the stiffened panel concept used in the design exploration. The reduction in design variables is made possible by the introduction of response surface methodology to map from the stiffness terms to the mass and margins of safety for the stiffened panel. To generate the response surface equations that represent mass and margin of safety, a precursory design of experiments is run to collect the necessary data. The presented methodology creates a design environment which is suited to the large-scale design exploration needed for considerations such as the placement of internal structural members or the tailoring of composites for aeroelasticity challenges.