Fluid Mechanics (Seventh Edition in SI Units), Frank M. White著, McGraw Hill Higher Education, 2014年4月発行, 定価9,479円

2283. Wing Primary Structure Weight Estimation of Transport Aircrafts in the Pre-Development Phase

The scope of the presented paper is to present a set of formulae, that can be used to compute the
manufacturers mass empty (MME) respectively the operators mass empty (OME) of a large civil jet
transport aircraft. In this paper, ‘large’ aircraft are aircraft having a maximum take of mass (MTOM) of
more than 40t respectively having 70 or more passenger seats in a typical layout.
The mass of the aircraft is split into the 10 main components of the aircraft (e.g. wing, fuselage…) and
one formula is developed for each component (part B to K). The sum of the component masses results
in the MME respectively OME of the aircraft (part L and M). The component masses, as well as the MME
and OME are defined according to the Airbus Mass Standard Reference Guide (Issue 3). A brief description
of the definition of each mass, as well as the main differences to the DIN 9020, which is normally
used within LTH, is given for each component.
Finally a sensitivity analyses is performed (part N), where the results between the preliminary aircraft
design tools VAMPzero and PrADO are compared. In the DLR development VAMPzero the statistical
formulae of this paper are implemented, while PrADO is developed during the last 15 years by the TU
Braunschweig and is based on semi-physical models. The analyses might give the user a better understanding
of the sensitivity behaviour, provided by the presented formula.
Please note that the data base, on which the following formulae are based on, consists of aircrafts having
similar operating conditions, certification requirements, configurations and design principals. Please
take care, if the formulae should be used for aircraft having characteristics beyond the one of the database.

Large Civil Jet Transport (MTOM > 40t) - Statistical Mass Estimation - Issue B

The present study developed a multi-fidelity workflow to derive physics-based conceptual design methods from models of higher-fidelity usually employed during preliminary aircraft design. The multi-fidelity workflow consists of a design of experiments, a multi-fidelity loop, and symbolic regression as surrogate modeling technique. Results are presented for conventional and unconventional aircraft configurations.

A Multi-Fidelity Workflow to Derive Physics-Based Conceptual Design Methods

2282. Semi-Analytical Method for Predicting Wing Structural Mass

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 – 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.

Felix Dorbath

Papers

Application of a Flexible Wing Modeling and Physical Mass Estimation System for Early Aircraft Design Stages