Browsing by Author "Landes-Dallat, Benjamin"

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Open Access
On physical aspects of cabin architectures using tolerancing methods
(2013) Landes-Dallat, Benjamin; Rudolph, Stephan (PD Dr.-Ing.)
In the conceptual design phase for the development of aircraft cabins the question about product architectures, spatial, mechanical and functional interfaces as well as the integration into the fuselage play a central role. While functional aspects are in the foreground for the conceptual design of cabin systems like the air distribution system or data systems, the architectures of the cabin modules like the stowage bins and the entire lining panels of the passenger compartment are mainly characterized by interdependencies between physical aspects, in particular between the geometrical shape, mechanical, functional and operational behavior as well as manufacturing aspects. The physical interfaces between the cabin modules, the fuselage structures and the attachment brackets are of high relevancy. Tolerance management, which defines the repercussions of tolerances already in the early conceptual phase of product development, here accomplishes important tasks. It can provide the required interconnection between geometrical shape, manufacturing-related deviation from nominal size, mechanical-functional behavior and the wide field of repercussions on manufacturing – in particular on the final assembly line. The analysis of physical aspects of cabin architectures consequently becomes a problem exceeding pure geometrical considerations. For this reason, methods based on a geometry paradigm for the generation and analysis of product data considering only geometrical aspects reach their limits concerning their validity for physical architecture aspects. On the other hand, the consideration of additional product data models in parallel is time-consuming. In particular, if several technical scenarios need to be compared, analysis methods like tolerance calculations are often omitted, since the relation between the modeling time and the validity of the calculation results based on values coming from heuristic or synthetic estimation procedures seems to be too unfavorable. In contrast, modern model-based methods, such as for instance, graph-based design languages enable interdisciplinary product models which are customized exactly to the needs of the respective problem. In addition to this, approaches with design languages comprising design rules offer the possibility for a fast and reproducible generation and modification of product data models. In the context of this dissertation so-called cabin design languages are developed that can describe and model physical aspects of cabin architectures including tolerancing. Key aspects of these design languages are the concepts of ‘physical components’ and ‘physical interfaces’ along with the associated aspects for physical integration like tolerances and installation processes. The implementation of these design languages consists of an extensive cabin-specific class diagram and a set of graph-based rules which together allow generating and calculating multiple variants of a technical scenario. The classes and rules also comprise synthetic estimations for component tolerances or masses, for example. The software-based implementation additionally provides routines which transform the compiled cabin models into analysis and visualization models. Amongst other, this comprises automatized means for the preparation of tolerance analyses, the calculation of analysis parameters in terms of ‘metrics’, the conceptual representation of manufacturing processes or the exchange of product data models. A use case demonstrates the practical benefit of executable design languages for the named problem. A cabin segment including the corresponding design rules is modeled. By means of parametrical and topological changes, several technical scenarios including the corresponding analysis and visualization models can be generated and evaluated. The following discussion examines the applicability of the presented method for industrial praxis. It shows, that conceptual tolerance management in conjunction with further analysis methods and supported by design languages can play a primary role for the industrial evaluation of physical aspects of cabin architectures in the conceptual design phase.