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2019-02-13
17:46
Diagnostic parameters determination of aircraft hydraulic system
Třetina, Karel ; Cäsar, Tomáš
The article presents methodology for application of information theory for selection of hydraulic system diagnostic parameters. Changes in technical state of the system are accompanied by a set of symptoms. Method of determining information value of each symptom by information theory is presented. A set of technical conditions and set of symptoms for a simple hydraulic system are determined. Matrix of technical state describing relations between technical conditions and symptoms is constructed. The four symptoms are determined by matrix analysis with use of information theory. These symptoms are chosen as diagnostic parameters and provide the most information about technical state of the hydraulic system.

Úplný záznam
2019-02-13
17:46
Modelling of health monitoring signals and detection areas for aerospace structures
Šplíchal, Jan ; Hlinka, Jiří
This paper is focused on Structural Health Monitoring (SHM) for aerospace use. It analyses the performance of commercially available finite element (FE) software packages for the simulation of propagation of ultrasonic guided waves (UGW) in typical aerospace structures. The purpose of the research is to support activities leading to the introduction of UGW based health monitoring on aerospace structures, as well as to support the design of future structures with integrated health monitoring. Activities are demonstrated on panels with growing complexity (adding different materials, sensors, damage types etc.). FE simulations are used to identify “detection areas” of UGW sensors. This output can be directly applied to the design of future aerospace structures with an integrated SHM system (to ensure the proper planning of the placement of UGW sensors).

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2019-02-13
17:46
Trends in development of aircraft for regional routes: impact on the european air transportation system
Nõmmik, Allan
The beginning of the twenty-first century in air transportation is characterized by increasing competition between (regular, i.e. not low-cost) airlines, which in its turn affects the low cost airlines by necessitating for them the operating of aircraft with larger seat capacity also on local routes, with the goal of operating the aircraft at lower cost per available seat kilometer. Taking into account the importance of air connections for the regional economy, the local authorities are obligated to support regional airports and impose public service obligations on some routes. This study examines the regional aircraft development after the air transportation market liberalization, while also delving into the background of differences in environments of operation in Europe and United States. To evaluate the regional routes’ equipment competitiveness, this research is focusing on to the regional aircraft fuel consumption which is the considerable factor for airline’s operating costs. Analysis of the differences between operating environments in Europe and the United States is based on an earlier review of the research findings on development of the markets after liberalization, and the role regional aircraft in air transportation system. Also, the comparisons of the profitability and airlines’ strategies in both regions are given. The results provide insights into the main drivers of regional aircraft design and development from the demand’s point of view.

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2019-02-13
17:46
Composite aircraft joint experimental testing with digital image correlation
Deák, Péter ; Kowalik, Michał
The main goal was to establish results of the individual joint strength characteristics used in composite laminate structure, in order to be used for design computations in airframe structures. A carbon-epoxy composite specimen includes a brass sleeve that is used to connect other metal parts by a bolt, used on light-weight category aircrafts. 11 specimens were tested and pulled by a tensile test machine. The tension mechanisms associated with failure modes of bolted joints in advanced composites is explained. The work is based on experimental test observations, performed by Instron 8516 servo-hydraulic testing machine and analyzed further by Digital Image Correlation (DIC) technique to define failure load of this metal-composite interconnection. Comparison of DIC results is made in parallel with test recorded data as verification. Conclusions include a failure analysis and observations learned during the experiment.

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2019-02-13
17:46
Layout optimisation method for active structural health monitoring
Červenka, Miroslav ; Koštial, Rostislav
This paper describes optimisation method for designing sensoric layout for Active Structural Health Monitoring (A-SHM) by Ultrasonic Guided Waves (UGW) on metal and non-metal (composite) materials. The SHM sensors need to be placed optimally in order to detect structural damage with high probability before the damage turns critical. Configuration of used optimisation algorithm for such task is not straightforward. Differential Evolution (DE) has two configuration parameters – the mutation factor F and the crossover rate CR – whose settings largely influence the solution quality the optimisation process can yield. For that matter we describe an elaborated a method to guide this selection towards good results using visual heat maps with the intent to select best DE’s variant and particular configuration to receive the most optimal SHM sensorics layout.

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2019-02-13
17:46
Simple universal nonlinear longitudinal flight simulation with avoiding of static and dynamic stability derivatives
Matějů, Jiří
This paper shows simple method to simulate nonlinear longitudinal flight dynamic of an aircraft in the most direct way. The method is based on physical principles of an analytical-empiric flight dynamics. Non-linearity, as stall or thrust dependent on velocity, can be included. Static and dynamic stability derivatives are not required but can be computed as an output. The model is applicable for various aircraft conceptions. Higher level model, for example, based on flight tests data, can be modified by low-level analytical methods, e.g. for modification of horizontal tail area. No special simulation software is necessary. The model is compared to linear model and flight test experiment. This model, together with valuable analytical-empiric data, might be applied for fast flight dynamic computations. Model is easily accessible and understandable even with basic knowledge of flight dynamic and computer programming. The main application of the method is conceptual design when high precision is not expected, even if VLM, CFD or flight test data can improve the precision.

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2019-02-13
17:46
Thermal conductivity of Cu7.2Ni1.8Si1Cr copper alloy produced via SLM and ability of thin-wall structure fabrication
Mašek, Jakub ; Koutný, Daniel ; Popela, Robert
Selective Laser Melting (SLM) as part of the Additive manufacturing industry is a metal printing technology that is considered promising to address the thermal integrity defects of a Heat Switch – the space technology currently under development. However, no thermal conductivity data of SLMed copper alloy Cu7.2Ni1.8Si1Cr are freely available. Therefore, three parts were fabricated and tested in an experimental thermo-vacuum chamber to reveal the material thermal conductivity. The samples analogous to the Heat Switch components were: a disk with inner holes and two cylinders with thin-wall web of 0.325 mm and 1.625 mm. Based on the previous experience with the copper alloy, fabrication was successfully processed with up to 5 % dimensional accuracy according to CAD model. The thermal conductivity evaluation process was improved by the implementation of heat transfer by radiation and the calculated thermal conductivity of SLMed Cu7.2Ni1.8Si1Cr was 3.4 times lower than the value of bulk material AMPCOLOY 944 with a similar chemical composition.

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2019-02-13
17:46
Teaching aircraft design through a blended learning method in a higher education
Kwiek, Agnieszka
A blended learning is a method which combines a few teaching methods. Usually it is a mix of classic teaching approach with using of online tools. A Nearpod is technology enhanced learning (TEL) tool which allows for creating an interactive presentation which can be delivered in a real time session or in a self-paced mode. The presentation can be displayed on a student’s computer or mobile phone. This paper presents how students experience can be enhanced by the implementation of a blended learning in aircraft design lectures. And how a Nearpod can be integrated into those lectures to help students develop such skills as creativity, critical thinking and problem solving, which are vital for aircraft design project and students’ further career in the aerospace sector. This study focuses on aeronautical students studying at the University of Brighton in School of Computing Engineering and Mathematics. Students group includes BEng., MEng. and BSc. Top-Up students who were enrolled in level 6 module - ME351 Aircraft Design and Management Project. Results reveal that students' attendance is higher than traditional lectures and the most favorite and helpful activities are quizzes & polls, draw it and fill blanks. Aerospace engineering students prefer Nearpod activities where they can choose an answer or draw it rather than writing it.

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2019-02-13
17:46
Vibration feedbacks in pilot-aircraft haptic interaction
Malalan, Nina ; Zikmund, Pavel
A research about different ways of encoding the distance information with vibrotactile feedback was done as part of a bigger project with the aim of designing a device which would help the pilot to achieve greater precision during the flight. Different kinds of stall warning devices and structural additions were already designed in the field of aviation, lingering only over attentional guidance. Therefore, a lack of spatial and movement guidance was detected. This paper lingers on this research which aimed to encode and evaluate haptic guiding methods.

Úplný záznam
2019-02-13
17:46
Design study of the heat switch base plate with single and multi-material topology optimization
Löffelmann, František ; Šplíchal, Jan
A miniaturized heat switch is a device under the development dedicated to control automatic cooling of a space instrument box. The design study presented in this paper focuses on a stiffness issue of the switch base plate which should assure good thermal contact with the instrument box. Due to inner deformations of the switch, base plate deforms which might decrease contact area needed to the heat transfer. Thus several design concepts of the copper base plate were investigated and multi-material additive manufacturing was reviewed. One approach was to decrease deformations of existing geometry by multi-material design by local exchange of copper with steel, first by engineering intuition, then by the stiffness based topology optimization, and finally with the layer-wise topology optimization better respecting manufacturing possibilities. Another approach was to change the geometry and use the topology optimization constrained with a flatness of the base plate but with single material. Finally, deformation changes of all the variants were compared.

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