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Relationship between tensile strength and hardness of aluminium alloys
Růžička, Martin ; Jetela, Václav (referee) ; Klement, Josef (advisor)
This thesis deals with relationship between tensile strength and hardness of aluminium alloys. The introduction provides an overview of aluminum aloys and their properties. In the following section there is an analysis of the processing of aluminum alloys. A large part is devoted to the course of precipitation hardening. The second part of the thesis contains a practical part, which describes the methodology of measuring hardness and tensile strength. The measurement process is described below. At the end, the measured data are processed into various graphs and their results are evaluated.
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Smart materials in aviation
Riger, Rostislav ; Jetela, Václav (referee) ; Klement, Josef (advisor)
This bachelor thesis deals with smart materials and their applications in aviation. The theoretical part explains what we mean by the term smart materials and what we want to achieve with their use. Further, these materials are sorted according to the principle of their function and described. The practical part is focused on specific applications of smart materials in aviation. Sometimes these are only theoretical applications that have not yet been used.
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Experimental evaluation of appropriate FDM technology for UAV production
Hubáček, Jan ; Klement, Josef (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with material analysis and design of technology for Fused Deposition modelling 3D printing method of unmanned aerial vehicles. Nine materials which are suitable for this application has been tested. Tension test has been used to determine mechanical properties of each material according ISO standards for plastics. Material had to met certain criteria, which are important for 3D print of aeroplanes, to pass to the next stage of experiment. Next three-point flexural test of wing has been used. In this test has been tested two glued sections of wing root and one separate section of wing. Results of tensile test and flexural test were compared and evaluated. It was discovered that material PLA, which is commonly used for printing aeroplanes, has not been overcome. Materials that seems to have better mechanical properties has been disadvantaged for its bad properties in 3D printing process.
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Age forming of aluminium alloys
Stanislav, Filip ; Petrásek, Miloslav (referee) ; Klement, Josef (advisor)
The diploma thesis is focused on the description and the verification of a relatively young creep age forming method. This method is based on a relaxation of stress and a creep of material, which occur by forming a part in the clamping tool during the artificial precipitation heat treatment at elevated temperature. After removing from the tool, the spring back and the residual stresses in the part are smaller compared to the conventional forming methods. This is mainly reflected in the increased fatigue resistance of the structure. The creep aging is only applicable to the precipitation heat treatable alloys. This thesis is focused on aluminium alloys, which are typical for the aerospace industry. The first part of the thesis describes principles of technology, its use in the aviation and material processes in the aluminium precipitation heat treatable alloys during the creep age forming. In the second part, there is a methodology of the verification of technology on samples made of the aluminium alloys ČSN EN AL-P 7075 and ČSN 424203 (approximate equivalent of ČSN EN AL-P 2024). Furthermore, a forming tool is designed, and experiments are performed according to the proposed methodology. At the end of the thesis, the experiments are evaluated and changes in the spring back of the samples are compared for three different methods of forming: the conventional cold clamping forming, the creep age forming and the creep age forming with an overaging.
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Application of thermoplastic composite materials on aircraft structures
Vráblíková, Lucie ; Symonov, Volodymyr (referee) ; Klement, Josef (advisor)
This bachelor thesis deals with thermoplastic composite materials in aircraft industry. The aims of the thesis are divided into three parts. The first part contains an overview of the basic properties of fibre-reinforced thermoplastics, their structure and characteristics. In the second part, there are introduced different technologies of manufacturing thermoplastics. The last part deals with applications of thermoplastic composite materials in aircraft industry.
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Evaluation of dynamic damage of composite structure
Štefanovič, Peter ; Jetela, Václav (referee) ; Klement, Josef (advisor)
The first part of the diploma thesis with name „Evaluation of dynamic damage of composite structure“ focuses on designing device for impact experiments and suitable laminate samples made from prepregs. The conditions and problems of impact tests are also demonstrated here. The second part of the thesis deals with non-destructive control of damaged specimens based on thermography. This is mainly the extent of defects in the impaired area and the evaluation of results using the pulse infrared thermography method. Finally, the relative deviation in the crack size comparison between the visual method and thermographic are compared. Consequently, the residual strength of the damaged samples against undamaged specimens are compared using bending tests.
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Problém černého pasažéra v Severoatlantické alianci v období 2006 - 2016 a implikace pro fiskální politiku
Richterová, Jitka ; Maule, Petr (advisor) ; Klement, Josef (referee)
The purpose of this thesis is to examine the problem of free riding in NATO with regards to fulfilling the criteria of defence expenditures as well as econometric analysis and interpretation of the defence expenditures of the member states in the period of 2006 to 2016. Using spearman correlation test, this thesis finds a significant positive correlation between GDP of member states and their defence expenditures. Explanatory variables include main economic indicators such as GDP, GNI, share of GDP devoted to defence expenditures, average annual change in defence expenditures, etc. Main findings include the conclusion that there is a significant level of free riding in the North Atlantic Treaty Organisation and that larger member states indeed bear the larger burden. Furthermore, based on having lower average defence expenditures than NATO in the examined period, the thesis labels nineteen of the member states as free riding, given that their defence expenditures are below the NATO average. After examining and analysing free riding in NATO the thesis also highlights the implications and recommendations for fiscal policy.
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Public investments into tertiary education in 1996-2001 period and the estimation of their rates of return.
Kozár, Filip ; Klement, Josef (advisor) ; Barák, Vladimír (referee)
Presented bachelor thesis focuses on tertiary education in the Czech republic. The main aim of this thesis is to estimate rates of return from public expenditures on tertiary education in the 1996-2001 period. The practical part deals with the evolution of human capital theory and two alternative theories - signalling theory and theory of screening. The next part goes in the direction of theory of human capital investments and their measurment methods. The analytic part starts with analysis of the tertiary education sector in Czech republic, including its historical development and international comparison. The second chapter is based on model definition. The model is further used to estimate net present values, internal rates of return and payback periods of public investments into tertiary education. The analytic part ends with a brief discussion and the result comparison with other authors. In a simplified way it is worthwhile for the state to finance tertiary eduction, the only exception being female pedagogical sector graduates.
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Database for laboratories and exercises in the course Aircraft Manufacture
Horčička, Marek ; Löffelmann, František (referee) ; Klement, Josef (advisor)
This bachelor thesis dealts with a selected part of the database for laboratories and exercises in the course of Aircraft Manufacture. The first part consists of a basic overview of aviation materials and the conditions of their thermal processing. It is about the technology of heat treatment of steel and alluminium alloys. In addition, the substrates for profile and tube forming technology are presented. The whole bachelor thesis is elaborated in accordance with the content of the course in the subject Aircraft Manufacture.
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