@conference {3615, title = {3615. Application Of A Flexible Wing Modeling And Physical Mass Estimation System For Early Aircraft Design Stages}, booktitle = {73rd Annual Conference, Long Beach, California}, year = {2014}, month = {05/2014}, pages = {23}, publisher = {Society of Allied Weight Engineers, Inc.}, organization = {Society of Allied Weight Engineers, Inc.}, address = {Long Beach, California}, abstract = {State-of-the-art models in preliminary wing design apply physics-based methods for primary structures while using empirical correlations for secondary structures. Using those methods, a detailed optimization such as e.g. rear spar positions or flap size is only possible within a limited design space. Novel structural concepts such as multi-spar flap layouts or the introduction of composite materials cannot be analyzed using statistical methods and require extended higher level structural modeling. Therefore, a flexible wing modeling and physical mass estimation system for early aircraft design stages is developed {\textemdash} the WINGmass system. The core of the interdisciplinary tool chain is a central model generator that automatically generates all analysis models from the DLR aircraft data format CPACS (Common Parametric Aircraft Configuration Scheme). For the automatic model generation, a large amount of engineering rules are implemented in the model generator, to reduce the amount of required input parameters and therefore to relieve the aircraft designer. Besides the multi-model generator, the tool chain consist of a structural finite element model (incl. wing primary structures, flaps, flap tracks, ailerons, engine pylon and landing gear), a structural sizing algorithm and loads models for aerodynamic, fuel, landing gear and engine loads. The wing mass estimation system is calibrated against real mass values of the wing primary structures and the trailing edge devices of the Airbus A320 and A340-200. The results of the calibrated tool chain are compared to the masses of the primary structures of the B747-100 and the aluminum baseline version of the MD-90-40X. The calibration factors for composite primary structures are derived from the composite version of the MD-90-40X. Finally, the benefits of the extended physics-based modeling and the application of the WINGmass system in an interdisciplinary aircraft design environment are shown in an aircraft design study. The objective of this study is to compute the optimal wing shape in terms of mission fuel as a function of the take-off field length. Therefore, a parameter variation of the wing and flap geometry is performed, the engine scaled correspondingly and the mission fuel evaluated.}, keywords = {10. Weight Engineering - Aircraft Design, 23. Weight Engineering - Structural Estimation}, url = {https://www.sawe.org/papers/3615/buy}, author = {Dorbath, Felix} } @conference {3547, title = {3547. Implementation of a Tool Chain for Extended Physics-Based Wing Mass Estimation in Early Design Stages}, booktitle = {71st Annual Conference, Bad G{\"o}gging, Germany}, year = {2012}, note = {

Mike Hackney Best Paper Award

}, month = {05/2012}, pages = {21}, publisher = {Society of Allied Weight Engineers, Inc.}, organization = {Society of Allied Weight Engineers, Inc.}, address = {Bad G{\"o}gging, Germany}, abstract = {

The state-of-the-art methods in preliminary wing design are using models employing physics-based methods for primary structures while using empirical correlations for secondary structures. Using those methods, detailed optimization as e.g. rear spar positions or flap size is only possible within a limited design space. Novel structural concepts such as multi-spar flap layouts or the introduction of composite materials cannot be analyzed using statistical methods and require extended higher level structural modeling. Therefore an interdisciplinary tool chain is developed for extended physics-based wing mass estimation. The tool chain consists of the following components: one central model generator, a structural finite element model, a structural sizing algorithm and loads models for aerodynamic, fuel, landing gear and engine loads. The structural finite element wing model consists of the following main parts: wing box, fixed trailing edge devices, movable trailing edge devices, spoilers, landing gears and engine pylons. The model generator is able to create several different kinds of track kinematics, covering most of the track types used in state-of-the-art aircrafts. To make the complexity of the model generation process feasible for one aircraft designer, a knowledge based approach is chosen. Therefore the central model generator requires a minimum set of easy-to- understand input parameters. This enables the aircraft designer to focus on the design and not on calculating input parameters. To include the tool chain in a wider multidisciplinary aircraft design environment, the aircraft parameterization CPACS (Common Parametric Aircraft Configuration Scheme) is used as central data model for input and output. The developed tool chain is implemented as flexible as possible to enable the designer to analyze also novel structural concepts or wing configurations. On wing configurational level, the tool chain can handle most types of different wing concepts, such as e.g. blended wing bodies, strut-braced wings and box wings. On the structural concepts side, the tool chain is able to handle various different rib and spar layouts and different materials (incl. composites).

}, keywords = {10. Weight Engineering - Aircraft Design, 23. Weight Engineering - Structural Estimation, Mike Hackney Best Paper Award}, url = {https://www.sawe.org/papers/3547/buy}, author = {Dorbath, Felix and Nagel, Bj{\"o}rn and Gollnick, Volker} } @conference {3564, title = {3564. Multi-Fidelity Wing Mass Estimations Based On A Central Model Approach}, booktitle = {71st Annual Conference, Bad G{\"o}gging, Germany}, year = {2012}, month = {05/2012}, pages = {18}, publisher = {Society of Allied Weight Engineers, Inc.}, organization = {Society of Allied Weight Engineers, Inc.}, address = {Bad G{\"o}gging, Germany}, abstract = {Although computational power is constantly increasing and Moore{\textquoteright}s Law is still not falsified, computational cost remains an essential barrier in aircraft design especially when a high number of design evaluations is necessary. This is especially true at the conceptual design stage of aircraft. While determining the characteristics of a new configuration the number of iterations and the low level of detail in the available data limit the analyses to simple empiric methods. Nevertheless, at a later point in the design it is necessary to determine parameters like the wing mass with higher-fidelity analysis modules. Especially when assessing configurations that lie outside of the well-known design space of conceptual design, empiric methods become unreliable. Examples to name include high aspect ratio and forward-swept wings. In this study a combination of an empiric method, a beam model and vortex lattice model for aerodynamic loads is introduced. While multi-fidelity approaches are already well known, this study focuses on the fact that all analysis modules derive their data from the same data model. Working on a central data model decreases the number of required interfaces and guarantees that all models relate to the same input data, i.e. a compliant geometry definition. This paper includes a design chain starting from the conceptual design tool VAMPzero as initiator for the more advanced models PESTwing and TRIMvl. Using the PESTwing tool a large design space will be explored. An equation for determination of the wing mass based on a physical model is then derived and compared to existing methods in conceptual design.}, keywords = {11. Weight Engineering - Aircraft Estimation, 23. Weight Engineering - Structural Estimation}, url = {https://www.sawe.org/papers/3564/buy}, author = {B{\"o}hnke, Daniel and Dorbath, Felix and Nagel, Bj{\"o}rn and Gollnick, Volker} }