1,721,013 research outputs found
Design techniques to support aircraft systems development in a collaborative MDO environment
Get PDFThe aircraft design is a complex multidisciplinary and collaborative process. Thousands of disciplinary experts with different design competences are involved within the whole development process. The design disciplines are often in contrast with each other, as their objectives might be not coincident, entailing compromises for the determination of the global optimal solution. Therefore, Multidisciplinary Design and Optimization (MDO) algorithms are being developed to mathematically overcome the divergences among the design disciplines. However, a MDO formulation might identify an optimal solution, but it could be not sufficient to ensure the success of a project. The success of a new project depends on two factors. The first one is relative to the aeronautical product, which has to be compliant with all the capabilities actually demanded by the stakeholders. Furthermore, a “better” airplane may be developed in accordance with customer expectations concerning better performance, lower operating costs and fewer emissions. The second important factor refers to the competitiveness among the new designed product and all the other competitors. The Time-To-Market should be reduced to introduce in the market an innovative product earlier than the other aeronautical industries. Furthermore, development costs should be decreased to maximize profits or to sell the product at a lower price. Finally, the development process must reduce all the risks due to wrong design choices.
These two main motivations entail two main objectives of the current dissertation. The first main objective regards the assessment and development of design techniques for the integration of the aircraft subsystems conceptual design discipline within a collaborative and multidisciplinary development methodology. This methodology shall meet all the necessities required to design an optimal and competitive product. The second goal is relative to the employment of the proposed design methodology for the initial development of innovative solutions. As the design process is multidisciplinary, this thesis is focused on the on-board systems discipline, without neglecting the interactions among this discipline with all the other design disciplines. Thus, two kinds of subsystems are treated in the current dissertation. The former deals with hybrid-electric propulsion systems installed aboard Remotely Piloted Aerial Systems (RPASs) and general aviation airplanes. The second case study is centered on More and All Electric on-board system architectures, which are characterized by the removal of the hydraulic and/or pneumatic power generation systems in favor of an enhancement of the electrical system.
The proposed design methodology is based on a Systems Engineering approach, according to which all the customer needs and required system functionalities are defined since the earliest phase of the design. The methodology is a five-step process in which several techniques are implemented for the development of a successful product. In Step 1, the design case and the requirements are defined. A Model Based Systems Engineering (MBSE) approach is adopted for the derivation and development of all the functionalities effectively required by all the involved stakeholders. All the design disciplines required in the MDO problem are then collected in Step 2. In particular, all the relations among these disciplines – in terms of inputs/outputs – are outlined, in order to facilitate their connection and the setup of the design workflow. As the present thesis is mainly focused on the on-board system design discipline, several algorithms for the preliminary sizing of conventional and innovative subsystems (included the hybrid propulsion system) are presented. In the third step, an MDO problem is outlined, determining objectives, constraints and design variables. Some design problems are analyzed in the present thesis: un-converged and converged Multidisciplinary Design Analysis (MDA), Design Of Experiments (DOE), optimization. In this regard, a new multi-objective optimization method based on the Fuzzy Logic has been developed during the doctoral research. This proposed process would define the “best” aircraft solution negotiating and relaxing some constraints and requirements characterized by a little worth from the user perspective. In Step 4, the formulation of the MDO problem is then transposed into a MDO framework. Two kinds of design frameworks are here considered. The first one is centered on the subsystems design, with the aim of preliminarily highlighting the impacts of this discipline on the entire Overall Aircraft Design (OAD) process and vice-versa. The second framework is distributed, as many disciplinary experts are involved within the design process. In this case, the level of fidelity of the several disciplinary modules is higher than the first framework, but the effort needed to setup the entire workflow is much higher. The proposed methodology ends with the investigation of the design space through the implemented framework, eventually selecting the solution of the design problem (Step 5).
The capability of the proposed methodology and design techniques is demonstrated by means of four application cases. The first case study refers to the initial definition of the physical architecture of a hybrid propulsion system based on a set of needs and capabilities demanded by the customer. The second application study is focused on the preliminary sizing of a hybrid-electric propulsion system to be installed on a retrofit version of a well-known general aviation aircraft. In the third case study, the two kinds of MDO framework previously introduced are employed to design conventional, More Electric and All Electric subsystem architectures for a 90-passenger regional jet. The last case study aims at minimizing the aircraft development costs. A Design-To-Cost approach is adopted for the design of a hybrid propulsion system
Development of a new conceptual design methodology for parallel hybrid aircraft
No full textIn this paper, an innovative methodology for the conceptual design of hybrid-powered airplanes is proposed. In particular,
this work focuses on parallel hybrid architectures, in which the thermal engine is mechanically coupled to an electric
motor, both supplying propulsive power during a limited number of flight phases, e.g. during takeoff and climb. This
innovative solution is the subject of several studies being carried out since the current decade. In this paper, a brief
overview of the works conducted by other researchers is provided. Then, an overall aircraft design methodology is
proposed, which is derived from the most renewed design algorithms. The original contribution of this work is represented
by the development of a methodology for the design of hybrid propulsion systems. Moreover, the proposed
method is integrated within a global aircraft design methodology. In particular, several effects of the innovative system on
the entire aircraft are considered, for instance the variation of the empty mass or the impacts on fuel consumption. The
paper ends with some case studies of the proposed design methodology, and a discussion of the obtained results is
provided
Guided procedure for the Zonal Safety Analysis in aircraft preliminary design
No full textDue to limited internal volume, often a high density of equipment installations is present on board an aircraft. For this reason, in case of a device failure, every component installed in close proximity could be damaged, causing a catastrophic domino effect. This paper presents a guided procedure for the Zonal Safety Analysis (ZSA) performed during the airplane conceptual design. This methodology allows aerospace engineers to carry out a devices installation on the aircraft taking into account the possible interactions among them in case of failure. In the Zonal Safety Analysis methodology, each equipment is characterized by a risk score, evaluating various types of accidents, for example mechanical breaks, electric damages, explosions. Considering every installed device and the possible spread of damages, a global risk score is obtained, which should be minimized in order to obtain a safer project as possible. In order to allow the engineer to conduct a Zonal Safety Analysis, a computer-aided software based on the ZSA methodology has been realized and presented in this paper. Thanks to a Graphical User Interface (GUI), many trade-off studies can be rapidly carried out and the safest solution can be designed. First, the tool requires the user to define the bays in which the aircraft is partitioned. Then, for each zone, the engineer selects all the equipment (e.g. avionic devices, electric generators, actuators, pumps) to be installed. These components and relative risk scores are included in a database compiled within the tool. Once every equipment has been selected, the risk level of every zone is evaluated, taking into account the possible interactions among all the close systems. Finally, the tool estimates the global risk score. All the results are shown to the user by means of tables and graphs. The engineer should comply the necessary changes (e.g. varying components location) in order to obtain a better design from a safety point of view. In the final part of the paper, a test case of the Zonal Safety Analysis methodology applied to an Unmanned Aerial Vehicle is presented. The obtained results are reported and discussed. This example demonstrates that the realized software can be useful to conduct a preliminary design a safer airplan
Antologia delle fonti e della critica di Luca Cambiaso. In: A CURA DI PIERO BOCCARDO E FRANCO BOGGERO. Luca Cambiaso: un maestro del Cinquecento europeo. p. 154-157, CINISELLO BALSAMO, MILANO: Silvana Editoriale, 2007. ISBN/ISSN: 978-88-366-0777-8
No full textAntologia delle fonti e della critica di Luca Cambiaso. In: A CURA DI PIERO BOCCARDO E FRANCO BOGGERO. Luca Cambiaso: un maestro del Cinquecento europeo. p. 154-157, CINISELLO BALSAMO, MILANO: Silvana Editoriale, 2007. ISBN/ISSN: 978-88-366-0777-
Method for Estimation of Electrical Wiring Interconnection Systems in Preliminary Aircraft Design
No full textThe aim of this paper is to present an original methodology for Electrical Wiring Interconnection System (EWIS) mass estimation at an early stage of aircraft design. More than 100 km of EWIS are installed on a modern civil aircraft with a mass of several tons. The aircraft manufacturers are increasing the primary generation voltage to reduce the system mass. The proposed algorithms are sensitive to the prominent EWIS design parameters such as voltage level, cable material, system architecture (distributed or centralized) and electrification degree of aircraft on-board systems. The equations assess the impact of these parameters on the EWIS mass, which is a useful feature during trade-off analysis in aircraft conceptual and preliminary design. The methodology and the necessary data to define the algorithms are reported together with a case study to validate the equations presented
Academic Course in Aircraft conceptual design and on-board systems preliminary design at Politecnico di Torino
No full textIntegration of on-board Systems preliminary design discipline within a collaborative 3rd Generation MDO framework
Get PDFThe integration of the on-board systems design discipline in a collaborative Multidisciplinary Design and Optimization (MDO) framework is presented in this paper. The collaborative MDO framework developed within the context of the EU funded H2020 AGILE project is selected as reference. The technologies developed or made available in the context of the AGILE project are employed for the integration within the MDO framework of ASTRID, an on-board Systems design tool owned by Politecnico di Torino. The connection of the tool with a common namespace (i.e. CPACS) and its implementation within two Process Integration and Design Optimization (PIDO) environments are described. An application study is eventually presented,
showing the benefits and the potentialities of the integration of the on-board systems design discipline within a collaborative MDO framework
Preliminary Study on OBS Electrification Efficiency for Advanced Supersonic Business and Medium Jet with Unified Engines
No full textThe present paper would investigate the effect of on-board systems masses and power required on propulsion system and aircraft mission performance of two reference supersonic aircraft. The on-board systems are even more investigated since their importance in engine and aircraft performance optimization and their effect can be only quantified through a multidisciplinary design. Moreover, with the introduction of more and all electric concepts for on-board systems, more flexibility in their design is now possible considering different architectures. In particular, the analysis involves a supersonic business jet and a supersonic medium jet with different performance, passengers number and propulsion system. The analysis shows different behaviours on the propulsion system parameters with power offtakes and systems mass variations for the two aircraft. The results are interesting for future systems architecture selection and to understand the effect of their integration to the propulsion system
A preliminary design study of maintenance and logistic infrastructure for MALE UAS
No full textThe present study has the aim of investigate the design of maintenance and logistic infrastructure for unmanned aerial vehicle (UAV). The study is focused on medium altitude and long endurance (MALE) UAV class. This subject has not yet been investigated in detail despite maintenance is quite crucial for aircraft which should to operate continuously even for 24 hours. To perform a conceptual and a preliminary design of these infrastructures several analysis have been carried out firstly to define a realistic maintenance program and secondly to design the maintenance hangar, the related repair shops and tools. Finally, the study is appropriately verified through computer aided design (CAD) tool
- …
