Development of a Structural Model of the CRM Configuration for Aeroelastic and Loads Analysis

Kurzfassung

The development of a structural finite element model for a generic transonic transport is presented. As configuration the publicly available geometry of the NASA Common Research Model (CRM) is used. The wing/body/nacelle/pylon/horizontal-tail configuration was originally developed for the the AIAA 4th Drag Prediction Workshop in 2009. The CRM is based on a long-range, wide-body transonic transport. It is intended by the DLR Institute of Aeroelasticity to use it as test case for assessment of flutter computation processes adopting CFD and ROMs. In order to enhance the CRM to be a completely defined aircraft configuration, various missing items and parameters are defined. This comprises the definition of a vertical tail as well as overall aircraft characteristics. The latter are the design speeds and masses, the center of gravity range and the component masses. For the development of the structural model a parametric modeling approach is applied, using methods from Computer Aided Geometric Design (CAGD). A design process is established, comprising the parametric modeling part, loads analysis, and the sizing of the structure considering also aeroelastic constraints. This approach enables a wide range of parameter variations in line with a sound structural design. The parametric design loop is a three step process. At first the set-up of parameterized simulation models (e.g. finite element model, aerodynamic model, mass models, and optimization model) is done component-bycomponent. Secondly, an aeroelastic loads analysis is performed with the assembled complete structural model for selected mass configurations. And thirdly, the structure is sized component wise. After adapting the jig shape of the wing, the process is repeated until the structural sizing and the jig-shape converge. The structural model for the generic configuration is available as detailed finite element model for the wing-like components, while the fuselage and the pylon are represented with beam elements. Further more a condensed structural model for two mass configurations is derived from the detailed model. It is defined at the so-called load reference axis (LRA).