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Light Aircraft Crashworthiness
Střecha, Daniel ; Šplíchal, Jan (referee) ; Löffelmann, František (advisor)
Passive safety in general aviation is still an area with significant shortcomings compared to the automotive industry. Whether it’s seat belts, airbags, or better materials that absorb impact energy, the automotive industry is years ahead. This bachelor thesis serves as a comprehensive overview of passive safety in light aircraft. It presents the main factors affecting human body tolerance and the criteria used in aviation construction regulations. One of the main objectives of this work was to provide an overview of safety features that can be implemented in light aircraft even after the aircraft has been put into operation. Selected features include seat belts, airbags, fire protection systems, ballistic parachute, and emergency locator transmitter (ELT). Each of these elements has different weights and costs. Among the more expensive and heavier systems is the ballistic parachute, which offers the significant advantage of safe landing in case of failure of the main control components of the aircraft but is offset by high acquisition and maintenance costs. The result of this work is also a questionnaire distributed among several pilots and operators of light aircraft. The evaluation showed that the favorite passive safety features among pilots include the ELT system, four-point seat belts, and ballistic parachute. Furthermore, the survey revealed that when choosing an aircraft, pilots would prioritize flight performance and characteristics over passive safety. In the future, it is essential to focus on raising awareness of passive safety during pilot training.
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Foam materials for impact absorption
Pilát, Adam ; Grim, Robert (referee) ; Löffelmann, František (advisor)
This diploma thesis discusses the topic of a polymeric foam impact energy attenuation system for emergency recovery parachute landing. It aims to improve the crew safety during emergency landing. The thesis contains research on methods of impact energy attenuation in aerospace. Research on existing use cases of such methods and systems is included. A computational model of foambag is proposed based on study of methods of polymeric foams mechanical characteristics modelling. The computational model is capable of identifying acceptable geometrical configurations of foambag based on inserted foam parameters, aircraft parameters and impact conditions. Experimental measurement of polyurethane foam with short reaction time is conducted. Identified material characteristics are used to improve the mathematic model. Based on the results from the mathematic model using the measured foam characteristics, a conception design is proposed. Important design points are identified and two possible approaches are proposed. The thesis results in conclusion that it is possible to design working energy attenuation system based on polymeric foam. There are however problems that need to be overcome to allow for real-life application of such system. These problems include mainly securing reliable function in any appliable conditions and system maintenance.
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Improvement of Wood Properties in Aviation
Novosád, Matěj ; Katrňák, Tomáš (referee) ; Löffelmann, František (advisor)
The work focuses on improving the useful properties of wood in aviation using known methods of its modification. The structural and mechanical properties of wood are described together with a basic overview of some aircraft structures using wood. A substantial part of the work consists of a description of individual modification methods, including their impact on the mechanical properties of wood. The work ends with a summary of some suppliers of wood as a material for aircraft construction and also with a description of some new methods of modification.
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Sandwich Insert Design of the Formula Student Monocoque
Velfl, Tomáš ; Šplíchal, Jan (referee) ; Löffelmann, František (advisor)
The bachelor thesis is devoted to the insert joints and wheel suspension attachments on the racing frame of a Formula Student vehicle. First, research was done to obtain the necessary knowledge on the subject. Then the external loads stressing the joints were experimentally and computationally determined. Before starting the actual design of the attachments, the effect of introducing local loads into the sandwich structure of the monocoque was investigated, firstly on small calibration samples. The first phase of testing was to verify the failure mechanisms, the interaction between the different components of the composite sandwich and to test different attachment designs using different materials. Based on the data obtained, the material libraries were refined, and computational models were developed and extended by parametrization. Thus, in the next step, the final designs of the individual suspension points meeting the predetermined objectives were iteratively created. During validation tests, the functionality of the design and sufficient oversizing were demonstrated. Technologies such as CT scanning were also used. The results were evaluated to determine further testing options and further improvements to the current solution.
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Buckling analysis of the load-bearing system
Majer, Tomáš ; Löffelmann, František (referee) ; Šplíchal, Jan (advisor)
The research part of the work summarizes the knowledge in the field of calculation of buckling stability and methods of heat transfer. The next part deals with the calculation of the buckling stability of two types of samples using an analytical approach, finite element method, and verified using experimental measurements. Finally, the work deals with CFD calculation for determining the temperature field on the examined samples, which is used to calculate the buckling stability with temperature influence.
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Structural optimization of the heat switch part
Zemek, Albert ; Mašek, Jakub (referee) ; Löffelmann, František (advisor)
This diploma thesis deals with the design of a structure for heat transfer path of miniaturized heat switch. The focus is on production using SLM additive technology. The aim is to assess the possibilities of using metal 3D printing on a part intended primarily for heat transfer. This work presents several concepts of structure arrangement, which are further analysed and evaluated. The results show the potential of additive technologies in this area and the proposed structures meet the heat transfer requirement according to the calculations used.
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Light sport aircraft engine replacement
Totogashvili, Nikolozi ; Jebáček, Ivo (referee) ; Löffelmann, František (advisor)
Práce je zaměřena na nalezení optimálního a nového motoru pro PS-28 Sport Cruiser, pro větší výkon a tah. Rotax 912 ULS je v současné době jediným motorem, který klient této práce (Czech Aircraft Works, dále jen CZAW) instaluje do letadel Sport Cruiser. Tato čtyřválcová pohonná jednotka má maximální vzletový výkon 100 hp. Pro náročnější zákazníky bude nabídka rozšířena o Lycoming O-235-L2C, což je také čtyřválcový motor s maximálním vzletovým výkonem 118 koní. Což znamená, že společnost bude mít větší možnost a klient bude mnohem spokojenější.
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Sandwich panels analysis under compressive load using finite elements methods
Seman, Matúš ; Löffelmann, František (referee) ; Mališ, Michal (advisor)
Bachelor thesis deals with possibilities of numerical modeling failure mechanism in sandwich panels using final element methods. The first part of the thesis presents theoretical introduction to requirements of sandwich structures and either mathematic formulation of constitutive relations. The purpose of the thesis was to set suitable approcahes of formulation instability problems with applying on laboratory samples. The analysis was done using nonlinear solvers in programes Patran/Nastran and the results have been properly evaluated with experimental work and analytical approach.
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Structural optimization of 3D-printed Unmanned Aerial Vehicle
Sladký, Martin ; Šplíchal, Jan (referee) ; Löffelmann, František (advisor)
This master thesis deals with the design of the internal wing structure of 3D printed flying wing VUT 714. As a part of this work was performed a load calculation, static strenght test, comparative FEM analysis and subsequently topology optimization was performed. The outcome of this master thesis is a rational design of the wing internal structure based on the load calculation and knowledge of effect of this load on the structure.
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Conceptual design of light folding hot-air balloon basket
Zatloukal, Tomáš ; Löffelmann, František (referee) ; Šplíchal, Jan (advisor)
The master thesis examines the design of small folding hot-air balloon basket intended for up to 3 people. It mainly focuses on the conceptual and structural design and their stress-strain analyses. After an initial introduction to the general terms used in hot-air ballooning, the thesis is focused on collecting information about folding lightweight baskets produces nowadays. The part deals with the conceptual design of the basket begins with the requirements. After choosing the method of basket folding, the thesis focuses on the structural nodes of the basket, and it also talks about the design of the burner frame. The penultimate part of the thesis verifies the selected structural designs from a strength point of view. The conclusion is devoted to the mass analysis.
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