Björn Nagel

An integrated design approach for low noise exposing high- lift devices

The DLR project LEISA combines and focuses activities in the research areas of high lift system design, flow control and aero-acoustic design methods, which have been carried out rather independently up to now. Furthermore, the competence in the fields of aerodynamics, aero-acoustics, structures and flight systems will be integrated to provide an interdisciplinary assessment of high lift system design for transport aircraft configurations. The project LEISA started at the beginning of 2005, so up to now only few results are available. This paper addresses the integrated design approach and first results for a noise reduced slat device and combined wind tunnel testing results for aerodynamics and aero-acoustics.

An approach to multi-fidelity in conceptual aircraft design in distributed design environments

In the present study we introduce a design environment consisting of a framework, a central model and a newly developed conceptual design module. The Common Parametric Aircraft Configuration Scheme (CPACS) is the standard syntax definition for the exchange of information within preliminary airplane design at DLR. Several higher fidelity analysis modules are already connected to CPACS, including aerodynamics, primary structures, mission analysis and climate impact. The analysis modules can be interfaced via a distributed framework. To initialize the design processes, capabilities are needed to close the gap between top-level requirements and preliminary design. Additionally, results of a design loop need to be merged to generate inputs for further iterations and convergence control. For this purpose we developed a conceptual design module based on handbook methods where the focus is set on multi-fidelity. For the upward change in level of detail a knowledge-based approach is used for the generation of CPACS models. This includes the geometry generation, as well as additional data such as the mass breakdown and the tool-specific inputs for further analyses in higher fidelity modules. The feedback loop is closed downwards by reducing the granularity from the CPACS data set back to the level of conceptual design methods. The conceptual design module is object-oriented and concepts, both for parameter and method replacement, are introduced. First results for multi-fidelity calculations are shown.

Integrated analysis and design environment for a climate compatible air transportation system

Aviation affects the Earth’s atmosphere and radiative balance through the emission of greenhouse gases, greenhouse gas precursors, aerosols, contrails and induced cirrus cloudiness. The resulting climate impact is a response of the complex interactions between the amount and type of emitted constituents, their geographical position, altitude and time of emission as well as the actual weather and climate situation. In 2005 aviation accounted for 3.5 % of the global anthropogenic radiative forcing (excluding the impact of contrail cirrus clouds). As the global air traffic is predicted to grow approx. 5% per year, the development of a climate compatible air transport system is of increasing importance for society and science. To achieve this goal, different technological and operational options can be applied to reduce the climate impact by air travel. The range of possibilities is wide, including new propulsion concepts such as open rotors or intercooler recuperative engine cycles, improved combustion chambers for low NOX and soot, novel aircraft configurations such as Blended Wing Bodies, innovative subsystem architectures for minimal engine cycle disturbance through secondary power off take and operational procedures such as multi-step operations and changed cruise altitudes for contrail avoidance. In order to provide a solid basis for decision and policy makers, the remaining uncertainties in climate modeling have to be reduced and the different options and their interrelations have to be assessed in a reliable way. To catch all relevant effects of the coupled disciplines, sophisticated numerical models for climate response, mission calculation, propulsion, aircraft subsystems and overall aircraft design are combined to an integrated simulation and assessment chain. In addition, further efforts are made to reduce remaining uncertainties in modeling emissions and their corresponding climate impact. This complex and multidisciplinary task further requires the contribution of experts from the included areas to ensure a secure evaluation of the obtained results. Here we present such an integrated approach as it is applied within the DLR project Climate compatible Air Transport System (CATS).

Towards a collaborative and integrated set of open tools for aircraft design

A third generation Multi-Disciplinary Analysis & Optimization setup includes the collaboration of a distributed team of disciplinary experts and their respective anylsis tool to perform aircraf ...

Extended physics-based wing mass estimation in early design stages applying automated model generation

This article introduces a tool chain for extended physics-based wing mass estimation. Compared to state-of-the-art tool chains, the physics-based structural modelling is extended beyond the wing primary structure. The structural model also includes the movable trailing edge devices including tracks, the spoilers, the engine pylons and the landing gear. The chain consists of the structural analysis model, models for aerodynamic, fuel, landing gear and engine loads as well as a sizing algorithm. To make the complexity of the model generation process feasible for preliminary aircraft design, a knowledge-based approach is chosen. This means that the analysis models are created partly automatically, which leads to a minimum set of required input parameters for the central model generator. The DLR aircraft parametrisation format Common Parametric Aircraft Configuration Scheme is used as central data model for input and output. Therefore, the chain can be easily included in a wider multidisciplinary aircraft design environment.

New methodology to explore the role of visualisation in aircraft design tasks

A toolbox for the assessment of engineering performance in a realistic aircraft design task is presented. Participants solve a multidisciplinary optimisation (MDO) task by means of a graphical user interface (GUI). The quantity and quality of visualisation may be systematically varied across experimental conditions. The GUI also allows tracking behavioural responses like cursor trajectories and clicks. Behavioural data together with evaluation of the generated aircraft design can help uncover details about the underlying decision making process. The design and the evaluation of the experimental toolbox are presented. Pilot studies with two novice and two advanced participants confirm and help improve the GUI functionality. The selection of the aircraft design task is based on a numerical analysis that helped to identify a ‘sweet spot’ where the task is not too easy nor too difficult.

Aeroelastic Design and Optimization of Unconventional Aircraft Configurations in a Distributed Design Environment

A Multidisciplinary Design and Optimization (MDO) methodology is presented, which uses a physics-based modeling approach for the preliminary structural design of unconventional aircraft configurations. Therein, static as well as dynamic aeroelastic stability constraints are accounted for at the early stage of the design process. A functional parametrization is applied for the description of the aircraft’s geometry. Several physics based analysis modules are orchestrated by an engineering framework to enable distributed multidisciplinary analysis and optimization. The method builds on DLR’s collaborative design environment, which uses the central data model CPACS to provide consistent model information in the analysis workflow. A knowledge based aeroelastic engine is developed to accelerate the integration of the disciplinary models and the subsequent aeroelastic analysis, and to automate the disciplinary couplings. The approach is tested in optimization test cases for a conventional wing design as well as for a Blended Wing Body configuration.

AGILE the Next Generation of Collaborative MDO: Achievements and Open Challenges

The EU funded AGILE project is developing the next generation of aircraft Multidisciplinary Design and Optimization processes, which target significant reductions in aircraft development costs and time to market, leading to more cost-effective and greener aircraft solutions. 19 industry, research and academia partners from Europe, Canada and Russia are developing solutions to cope with the challenges of collaborative design and optimization of complex products. In order to accelerate the deployment of large-scale, collaborative multidisciplinary design and optimization (MDO), a novel methodology, the so-called AGILE Paradigm, has been developed. The AGILE Paradigm is a “blueprint for MDO”, guiding the deployment and the execution of collaborative “MDO systems” for complex products practiced by cross-organizational design teams, distributed multi-site, and with heterogeneous expertise. A set of technologies has been developed by the AGILE consortium in order to enable the implementation of the AGILE Paradigm, and to support the design and the optimization of novel aircraft configurations. The AGILE Paradigm ambition is reduce the lead time of 40% with respect to the current state-of-the-art. This paper addresses the MDO challenges tackled by the AGILE Paradigm. An overview of the main AGILE Paradigm’s underlying architecture is described. The paper presents a preliminary assessment of the AGILE Paradigm application, and provides an overview of the main achievements enabled by its implementation for the solution of selected aircraft design and optimization use cases. The paper concludes with an overview of the challenges still open and an outlook of the AGILE Paradigm.

Lessons learned in participative multidisciplinary design optimization

Research into future air vehicles incorporating novel technologies is characterized by a high number of interacting disciplines which need to be considered. Despite advances in numeric interfacing techniques for participative Multidisciplinary Design and Optimisation (pMDO), it is not well understood how to build a team of specialists who jointly operate shared tools and gain system level insight. This contribution shifts focus to the human MDO participants and their working environment. Three aspects of collaboration are considered: (a) design of cognitive experiments to measure engineering performance in different settings; (b) integration of prior experience through a Lessons Learned process; and (c) the application of the above into the enhancement of Integrated Design Laboratory (IDL). The pronunciation of competence and working environment, rather than software tools or data, opens opportunities for attractive use cases.}

Aerostructural Interaction in a Collaborative MDO Environment

The work presents an approach for aircraft design and optimization, developed to account for fluid-structure interactions in MDO applications. The approach makes use of a collaborative distributed design environment, and focuses on the influence of multiple physics based aerostructural models, on the overall aircraft synthesis and optimization. The approach is tested for the design of large transportation aircraft.