Distributed multilevel optimization for complex structures

Abstract

Optimization problems concerning complex structures with many design variables may entail an unacceptable computational cost. This problem can be reduced considerably with a multilevel approach: A structure consisting of several components is optimized as a whole (global) as well as on the component level. In this paper, an optimization method is discussed with applications in the assessment of the impact of new design considerations in the development of a structure. A strategy based on fully stressed design is applied for optimization problems in linear statics. A global model is used to calculate the interactions (e.g., loads) for each of the components. These components are then optimized using the prescribed interactions, followed by a new global calculation to update the interactions. Mixed discrete and continuous design variables as well as different design configurations are possible. An application of this strategy is presented in the form of the full optimization of a vertical tail plane center box of a generic large passenger aircraft. In linear dynamics, the parametrization of the component interactions is problematic due to the frequency dependence. Hence, a modified method is presented in which the speed

CAD-Centric Dynamic Workflow Generation

“…This predominant role held by CAD models in the product development process conflicts with the role of CAD during trade studies. Trade studies are often done by performing optimizations which drive slave applications, as seen in Figure 1-3, to perform design iterations (Wind 2008, Wang 2005, Tappeta 1999). Trade studies performed in this configuration remove the engineer from the design loop, leaving design decisions to the whims of the optimization software.…”

Probabilistic optimisation of mono-stringer composite stiffened panels in post-buckling regime

“…Herencia et al (2008a) proposed a two-level approach for layup optimisation of composite stiffened panels. A multi-level approach was developed by Wind et al (2008), who conducted local and global optimisation on a multi-component structure. Further studies were conducted by Herencia et al (2008b) who proposed a two-step method for optimisation of anisotropic composite stiffened panels.…”

Robust design and optimization of composite stiffened panels in post-buckling

“…Liu et al (2000) developed a two-level optimization procedure for analysing a composite wing where the response at the lower (panel) level was used to build a Response Surface for the optimal buckling load that is used later for the global (wing) problem optimization. Wind et al (2008) developed a multilevel approach to optimize an structure consisting of several components. It was optimized as a whole (global) as well as on the component (local) level.…”