A Unified Approach to Modeling Multidisciplinary Interactions

There are a number of existing methods to transfer information among various disciplines. For a multidisciplinary application with n disciplines, the traditional methods may be required to model ) ( 2 n n − interactions. This paper presents a unified three-dimensional approach that reduces the number of interactions from ) ( 2 n n − to n 2 by using a computer-aided design model. The proposed modeling approach unifies the interactions among various disciplines. The approach is independent of specific discipline implementation, and a number of existing methods can be reformulated in the context of the proposed unified approach. This paper provides an overview of the proposed unified approach and reformulations for two existing methods. The unified approach is specially tailored for application environments where the geometry is created and managed through a computer-aided design system. Results are presented for a blended-wing body and a high-speed civil transport. ∗ Research Scientist, Multidisciplinary Optimization Branch, AIAA Senior Member † Senior Technical Fellow, Aeroelasticity and Optimization, AIAA Associate Fellow Introduction A key element in the application of multidisciplinary design optimization (MDO) to an engineering system is the introduction of a consistent geometric representation. Such a representation guarantees that the same geometry model is used to derive the computational models required for various disciplinary analyses. By utilizing computeraided design (CAD) for consistent geometry representation, it is easier to analyze complex configurations with higher-fidelity tools such as computational fluid dynamics (CFD), computational structural mechanics (CSM), or detailed finite-element analysis. A feature that characterizes multidisciplinary analysis and optimization is the modeling of interactions among various disciplines. For example, the strong interactions between CSM and CFD can prompt physically important phenomena such as those occurring in aircraft due to aeroelasticity. Correct modeling of these complex aeroelastic phenomena requires a coupling of CSM and CFD for a flexible structure (e.g., airplane). In a multidisciplinary environment, various disciplines must represent the same configuration geometry, and data from each discipline must be available consistently to all the disciplines. The data may be scalar (e.g., pressure and temperature), vector (e.g., deflection and heat transfer), or integrated quantities (e.g., aerodynamic and thermal loads). The data transfer process may be subjected to additional constraints, such as conservation of forces, moments, and energy. The focus of this paper is the transfer of data between dissimilar grids (most models do not share the same nodal locations at the interface).