1,720,984 research outputs found
Physical analysis
No full textThis main activity of engineering is described and analyzed within the frame of the whole product development and in connection with the Functional and Logical Analysis. The two test cases are explored to describe different examples of physical modeling, considering the dynamic behavior of a rotor, actively suspended and the performance in de-icing activity of the on-board system of the commercial aircraft selected for this example. Some numerical methods are even described as they are applied in the two proposed test cases
The systems engineering
No full textMany definitions of the Systems Engineering are proposed, and analyzing some differences between them help to highlight contents and open issues, as they are described in this chapter. Nevertheless, a short historical outline could be helpful in appreciating some characteristics of this methodology, which are even more detailed by a wide literature, herein briefly described. Furthermore, an overview of technical standards dealing with the Systems Engineering is added, to define a roadmap for a deeper education in this field
Systems, customer needs and requirements
No full textA preliminary and relevant step of the whole process includes a complete collection of customer needs and a suitable elicitation of requirements. This activity is never trivial and requires to be suitably formalized. This is done by resorting to the test cases of this handbook. In the meanwhile, the role of stakeholders is even investigated and defined. Requirements are then defined, classified and categorized for a better implementation of the MBSE. A direct implementation of requirements analysis is performed for the two examples
Logical analysis
No full textBefore that a real architecture of system could be defined, by selecting some suitable components, available on the market, it is suggested to describe the Logical architecture of the system, to investigate the most promising solutions available in terms of exploitable technology. This leads to perform a Logical Analysis, as is herein described. Relations between Functional and Logical Analyses are investigated. Examples are exploited to show some properties of this analysis. At the end of chapter, the main items of the Logical Analysis are resumed
Functional analysis
No full textThe next step of Functional Analysis is herein investigated. The existing relation between Operational and Functional Analyses is first defined. The implementation of the Functional Analysis is then performed, through the SysML. How the traceability and the requirements allocation are assured is shown. The system behavior is fully analyzed. The functional architecture is then derived, for the two test cases. Finally, the main items of the Functional Analysis are resumed
System verification and validation (V&V)
No full textA preliminary overview on the connection between Application Lifecycle Management and Product Lifecycle Management is proposed, by introducing the contents and the strategies of the Verification and Validation activities. The chapter should allow the Reader distinguishing the two activities and even the tools and the goals related. A comparison between the typical approaches applied in Software and Hardware Engineering, respectively, is briefly deployed. A preliminary relation with the RAMS analysis, dealing with Reliability, Availability, Maintainability and Safety, is discussed, especially in the two test cases
Heterogeneous simulation
No full textAs a matter of facts, interoperating tools and integrating the functional and physical modeling of systems within a unique toolchain is one of the most challenging issues of the Systems Engineering technology as is currently known. Therefore, this topic is analyzed in this chapter, one that the set of analyzes required was performed. Strategies, tools, limitations and benefits of the heterogeneous simulation are here analyzed, even through the two test cases
Flight Control System Design and Sizing Methodology for hypersonic cruiser
Full text linkFlight Control System is considered a key enabler for future high-speed aircraft and therefore, the anticipation of its impact onto the aircraft layout and performance is crucial. On one side, a preliminary characterization of the control surfaces is essential for a precise estimate of the aerodynamic characteristics of the vehicle throughout the mission. On the other side, traditional design approaches widely used in subsonic aircraft design and based on on-design and standalone system sizing, may lead to wrong estimates of the peak power demand. Conversely, typical supersonic and hypersonic design solutions are investigated by means of numerical simulations which guarantee higher accuracy but may not be directly applicable during the early design stages. Therefore, this paper discloses an innovative methodology (i) to anticipate the Flight Control System design of future high-speed aircraft at conceptual design stage, (ii) to properly consider the interactions with other subsystems and (iii) to properly predict the behavior of the Flight Control System throughout the entire mission. The integrated subsystems design methodology disclosed in this paper starts with the suggestion of the most promising semi-empirical models for control surfaces geometrical definition. The newly defined surfaces can be analyzed to predict their single contribution to the vehicle lift and drag coefficients. At this stage, the interaction with the propellant system is fundamental to identify the minimum surfaces deflections required to guarantee the aircraft trim. Indeed, in order to minimize the exploitation of control surfaces and thus limiting the detrimental effects onto the aerodynamic efficiency, propellant tanks can be properly shaped and integrated on board, and ad-hoc depletion sequencies can be adopted to match the desired center of gravity shift throughout the mission. Maximum required control surfaces deflections are used as inputs for the estimation of hinge moments to be counteract by the actuation system. A novel approach is here suggested to extend the formulation available in literature beyond the transonic regime. Eventually, the Flight Control System design is completed with the selection of actuators and finalization of the System architecture including power distribution lines and connections with the avionic system. The integrated design methodology has been developed in the context of the H2020 STRATOFLY Project and it has been exploited for the design and sizing of the Flight Control System of the STRATOFLY MR3 vehicle, a Mach 8 waverider concept for civil antipodal flights
Innovative Multiple Matching Charts approach to support the conceptual design of hypersonic vehicles
Full text linkSeveral well-established best practices and reliable tools have been developed along the years to support aircraft conceptual and preliminary design. In this context, one of the most widely used tool is the Matching Chart (MC), a graphical representation of the different performance requirements (curves representing the thrust-to-weight ratio (T/W) requirement as function of the wing loading (W/S)) for each mission phase. The exploitation of this tool allows the identification of a feasible design space as well as the definition of a reference vehicle configuration in terms of maximum thrust, maximum take-off weight, and wing surface since the very beginning of the design process. Although the tool was originally developed for conventional aircraft, several extensions and updates of the mathematical models have been proposed over the years to widen its application to innovative configurations. Following this trend, this paper presents a further evolution of the MC model to support the conceptual design of high-speed transportation systems, encompassing supersonic and hypersonic flight vehicles. At this purpose, this paper reports and discusses the updates of the methodology laying behind the generation of the MC for high-speed transportation. Eventually, the results of the validation of the updated methodology and tool are reported, using as case study, the STRATOFLY MR3 vehicle configuration, a Mach 8 antipodal civil transportation system, currently under development within the H2020 STRATOFLY project
Propellant subsystem design for hypersonic cruiser exploiting liquid hydrogen
Full text linkThe possibility of establishing a new paradigm for commercial aviation towards high-speed flight in the next decades shall be inevitably preceded by the increase of Technology Readiness Level for those relevant enabling technologies associated to propulsion, thermal management and on-board subsystems, with particular attention also to environmental sustainability and economic viability of the proposed concepts. New design methodologies for both aircraft and on-board subsystems design shall then be based on holistic approaches able to catch the strong interactions between vehicle configuration, mission and subsystems architecture, which characterize high-speed aircraft layouts. This paper proposes a methodology for the preliminary sizing of propellant subsystems for liquid hydrogen powered hypersonic cruisers. Making benefit of traditional approaches, the process aims at introducing new design aspects directly connected to the peculiar multifunctional architecture of on-board subsystems for high-speed vehicles, so to be able to include additional analyses in early design stages, especially in case of high level of on-board integration. Notably, impact of requirements for Center of Gravity control, thermal, and, in general, energy management are considered as integral part of the method, with crucial implications on architecture selection. After the introduction of design algorithms for subsystem sizing, the STRATOFLY MR3 hypersonic cruiser is taken as reference case study in order to provide a practical example of application of the proposed approach on a highly integrated platform
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