Parametrisation and Automation in Preliminary Design of Aircraft Structures

Kurzfassung

The aircraft design process can generally be classified into three major phases. In the conceptual design phase the viability of different designs is investigated with respect to market and customer requirements. It usually ends with the identification of suitable aircraft designs. Subsequently, in the preliminary design phase, trade studies are conducted. The aim of this phase is the generation of a loft and to find a basic design which will then be optimized in the concluding detailed design phase. The investigations in the preliminary design phase comprise the generation of numerous different analytical and Finite Element (FE) models including their corresponding boundary conditions. Though computational power has increased significantly over the past few years the model generation process still is a time-consuming task. Due to the high number of analyses it is also a source of possible errors which eventually may lead to time- and cost intensive redesign during the detailed design stage. Therefore, the preliminary design phase is of high importance in the overall design process. As different disciplines influence each other, the use of Multi Disciplinary Optimisations (MDO) is becoming more and more state-of-the-art as it combines various disciplines aiming to find an optimal aircraft configuration for the requested missions. This approach requires coupling in- and output of the different tools in different disciplines which in turn calls for a common data format serving as an interface. The increased detail level of computational models and the amount of parameters to be evaluated for each configuration call for the composition of automated processes. Based on the parametrised DLR aircraft description CPACS (Common Parametrised Aircraft Configuration Scheme), several different tools for structural sizing and crashworthiness proof of air- and rotorcraft have been developed at the Institute of Structures and Design (DLR-BT): For modelling purposes the tools TRAFUMO (TRansport Aircraft FUselage MOdel) and ROFUMA (ROtorcraft FUselage Mass Assessment) have been established. Static sizing against strength and stability is conducted using S-BOT+ (Sizing roBOT+) tool while crashworthiness is investigated using AC-CRASH (AirCraft CRASH). In this paper an overview of the tools developed and used at DLR-BT will be given. Exemplary models and applications will be presented to illustrate the positive impact on efficiency in aircraft design. Concluding, future development steps and possible applications will be discussed.