1,721,016 research outputs found
Transdisciplinary Engineering Research Challenges
Get PDFTransdisciplinary research (TDR) has been the subject of discourse in the past few decades, but has not been studied much in the context of engineering problems. Many engineering problems can be characterized as ill-defined, like open innovation, adoption of new technology, business development, and the adoption of the Industry 4.0 concept. Transdisciplinary engineering research (TDER) is also performed in large projects by multi-disciplinary teams, as in TDR projects, including stakeholders and people from practice. Such projects may last long, often years. In such large projects, the involved disciplines should include both engineering disciplines as well as disciplines from social sciences. In this paper we address the challenges that exist in adopting a TDER approach. Universities need to prepare students to work in TDER projects. We discuss the current situation in transdisciplinary engineering education (TDEE) and identify challenges that need to be addressed for including TDEE in curricula. The paper ends with a summary and ideas for further research
Maintenance in aeronautics in an industry 4.0 context: The role of ar and am
No full textThe paper discusses how Industry 4.0 could impact practitioners performing maintenance in aviation. The attention has been on Augmented Reality and Additive Manufacturing, which can support maintenance tasks and spare parts production respectively. Advantages and open issues are widely discussed and couple of case studies dealing with realistic scenarios are presented to support what has been proposed by the authors. The intention is to demonstrate that AR and AM are viable tools in aviation maintenance, even if effort is necessary to develop an appropriate regulatory framework, required before the introduction of these technologies in the maintenance process. Once applied to real maintenance tasks by airline companies, the practitioning community can develop best practices and the necessary regulation pertaining to maintenance and repair of aerospace systems using AR and AM technologies
Identification of Strategic Maintenance
No full textAirline Maintenance and Engineering (M&E) organizations face accidental damages on their fleet of aircraft as part of daily practice. As this type of damage is stochastic in nature, the approach towards repairing accidental damage is reactive in practice. However, it is possible to predict future long-term (strategic) demand for maintenance resources associated with accidental damages and use this to identify required capacity. To achieve the mutually related goals of prediction of future repairs and determination of capacity, a novel approach for integration of reliability modelling and inventory control is presented in this paper. Here, the concept of inventory control has been specifically applied to determine the maintenance capacity by taking into account the stochastic demand related to unscheduled repairs following from accidental damages. To predict demand, a Non-homogeneous Poisson Process (NHPP) reliability model has been adopted. The reliability model includes superpositioning, through which failure behaviour at aircraft fleet-level can be estimated and subsequently simulated. The resulting demand is fed into a single-system, single location base-stock inventory model. This allows for determination of strategic capacity based on optimum costs as well as service level requirements. A case study has been performed on a fleet of Boeing 777 aircraft of a major European airline. The results prove the feasibility of adopting an integrated approach towards strategic capacity identification, using real-life data to predict future demand occurrence.Air Transport & Operation
Methodology for multidisciplinary aircraft design under consideration of hybrid-electric propulsion technology
No full textAgainst a background of increasing energy demand and rising fuel prices, hybrid-electric propulsion systems have the potential to significantly reduce emissions of aircraft, particularly in the light aircraft sectors.
Within this thesis, a novel design methodology for aircraft using hybrid-electric propulsion is presented. This methodology can be used stand-alone, or it can be integrated into existing aircraft design frameworks. It allows for the design of optimal aircraft under consideration of the additional degrees of freedom due to hybrid propulsion systems. To achieve this goal, the components of hybrid-electric propulsion systems are modeled in a way suitable for conceptual aircraft design. The models of the individual components are then assembled to a global propulsion system model.
Thorough testing of the models and the methodology is performed, and adequate results are obtained. Test cases are two real-world sizing exercises of different aircraft, and a comparison against a different design method, which was developed in parallel to this work by another researcher. The validation process confirmed the correct implementation of the method and the sensible modeling of the aircraft's components and physics.
The methodology is used to assess the impact of this new design approach on aircraft performance, efficiency, and overall configuration design. For this purpose, four different aircraft are considered: a typical general aviation design, an unmanned surveillance aircraft, a vertical take-off and landing aircraft, and a short take-off and landing aircraft. The vertical- and short-take-off aircraft will be considered because these capabilities are highly demanding with respect to the propulsion system. Therefore, aircraft designed for such capabilities might offer a high payoff if hybrid propulsive methods are considered.
The analyses conducted within this thesis indicate that hybrid-electric propulsion systems offer practically no benefit compared to conventional designs for aircraft that are intended to be flown as fast as possible for most of their mission. Aero-propulsive coupling might change that result. However, modeling and assessing such effects is not part of the scope of this thesis. That topic should be assessed in further research.
Nevertheless, hybrid-electric propulsion can indeed be of benefit for aircraft that require high excess power but only use that power for short periods at a time. In these cases, significant savings of energy and cost are possible compared to current conventional designs.PeerReviewe
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Decision Support Tool for Concurrent Engineering in Space Mission Design
No full textThe concurrent engineering (CE) approach has been successfully applied to the early design phase of space missions. During CE sessions, a software support is needed to allow multidisciplinary design data exchange. At the moment, a spreadsheet-based solution enhanced with macros is used at the German Aerospace Center (DLR) to create a system model of a space mission during the early design phase. Now there is an increasing demand to take advantage of this system model and provide data analysis features which improve the decision making during CE sessions. Since the current approach is limited for such analysis, DLR has started developing a new tool called Virtual Satellite. It offers extended software support required by the Concurrent Engineering Facility of DLR in Bremen. On top of the previous spreadsheet functionalities, it provides means for online data analysis and system modeling. The results of these data analyses are presented to the discipline experts using different views which help in performing an early design optimization. In this paper, the impact of these views on the decision making during the AEGIS space mission study is presented as a proof of concept
An Integrated Laboratory for Collaborative Design in the Air Transportation System
No full textAt the Institute of Air Transportation Systems of the German Aerospace Centre (DLR), methods for collaborative design are systematically developed and assessed. These collaborative design approaches are used to gain knowledge on the overall air transportation system. A collaborative working environment–the Integrated Design Laboratory (IDL) is established. It forms an experimental technical platform for integrating the competences of disciplinary experts within DLR. Within the laboratory, technical solutions, collaboration methodologies and organisation of teamwork are provided and evaluated to enhance multimodal communication between specialists. In this paper, experiences from previous DLR projects as well as observations on similar facilities are used to identify research areas. In a pilot study, requirements for the design room are laid out. The initial setup of the laboratory is presented, after which a research roadmap for en-hancing collaborative design at DLR is presented
Design and Development of a Propulsion System for a Water-Air Unmanned Vehicle
No full textThis work aims to contribute on the design of a Bimodal Unmanned Underwater and Air System (BUUAS). This research project will first present background informations of current hybrid UAV concepts with a focus on the different types of propulsion mechanisms used in air/water transition. Then a brief description of BUUAS will lead to requirements for the transition mechanism that this work aims to develop. After a section dedicated to the description of a short-impulse thruster layout, theoretical and experimental approaches are used to determine the amount of thrust generated. As second design step, a simplified UAV version is used to test the transition phase using the designed thruster. Finally, a section is dedicated to a design layout description with the thruster and an optimized propeller. Future work is proposed to continue in the development of this project, with a short description of folding wing and propulsion system integration concepts
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