Buch, Englisch, Band 2018-11, 213 Seiten, Format (B × H): 148 mm x 209 mm
Reihe: NFL-Forschungsberichte
Buch, Englisch, Band 2018-11, 213 Seiten, Format (B × H): 148 mm x 209 mm
Reihe: NFL-Forschungsberichte
ISBN: 978-3-947623-06-8
Verlag: Technische Uni Braunschweig NFL
Abstract
The current applications of the composite materials in the commercial aviation are carried out only on the material level by slight adjustments while maintaining the traditional design to-pology, due to the fact that the composite materials are prone to each manufacturing step lead-ing to formidable challenges particularly in seeking innovative concepts. Therefore, multi-disciplinary criteria must be addressed in the design of innovative composite airframes such as structural failure, weight savings, economic efficiency, manufacturability, production de-viations and defects leading to reoccurring manual phases between the design engineers and manufacturers. Existing design methodologies lack in the comprehensive consideration of such aspects. Hence, the realisation of cutting-edge composite designs aiming to reduce struc-tural weight as well as the direct operating costs, becomes inefficient and time-consuming by the current design methodologies. The aim of the dissertation is to develop and demonstrate a multi-criteria design methodol-ogy for the production-oriented design of innovative stiffened airframes. The methodology is composed based on the interdisciplinary interaction between the structural design and the production during the product development covering the above addressed issues in the com-posite design. For the implementation of the methodology, a multi-disciplinary design envi-ronment was built by the interdisciplinary parametric representations of structures and proc-esses in an interactive framework consisting of several modules. The structural modules carry out automated Finite Element (FE) modelling for the stability and material failure calculations of a wide variety of stiffened panel designs whereas the process modules conduct manufacturing and cost analysis of arbitrary components. This includes, in particular, manufacturability analysis of an automated fibre placement process, including the tow-gap estimation which is validated by an experimental setup as well as the drapability analysis of fabrics with the identification of fibre misalignments which is coupled with the FE models. Moreover, the economic aspects of the structural design are addressed by estimating the production costs through the process models belonging to a user-defined production chain. The framework composes interdisciplinary criteria into a fitness value by an evaluation model for the ranking and the development of structures (individuals) by a coupled evolutionary optimisation environment. The applicability of the developed methodology is first demonstrated by the cost-weight optimisations of conventionally stiffened panel concepts with varying stiffener topologies under the influences of associated process histories. Consequently, the framework is employed for the cost-weight optimisation of a newly developed unconventionally stiffened Lattice-Grid panel under the influences of newly developed manufacturing systems. The developed framework generates a set of process-oriented (defect-free) designs with realistic cost-weight trade-offs as well as their production chain for the preference of the user. The obtained solutions satisfy the multi-disciplinary criteria such as structural integrity, manufacturability and economical requirements based on a user defined business model.
