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Three dimensional force sensor
Černý, Hynek ; Krejčí, Petr (referee) ; Houfek, Lubomír (advisor)
The bachelor’s thesis dealt with the design of a force sensor, which was supposed to do measurements of forces in three axes independently. The another required output of the work was creation of drawings. The design and optimalization of shape and dimensions of the sensor was made mainly in program called ANSYS. An important part of the work was the expression of final relations for the calculation of forces both analytically using simple elastic strength and the numerical finite element method. The last part of the work was an experimental measurement, which was supposed to verify accuracy of both methods for forces expression and also correct functionality of the sensor.
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THE UNCERTAINTIES DEFORMATION AND STRESS USING THE STRAIN GAUGES
Dokoupil, Pavel ; Vlk, Miloš (referee) ; Koška, Petr (referee) ; Habán, Vladimír (advisor)
The dissertation thesis deals with the determination of uncertainty of strain measurement and the stress using resistance strain gages. You can find two methods to define the uncertainty in the thesis, GUF and MMC, and both are applied for measurements carried out with resistance strain gages. Definition of the measurement uncertainty was set for the strain measured by uniaxial and biaxial strain gages. The uncertainty of the stress was defined for linear strain gages, T Rosettes and Rosettes. There were universal mathematic-technical models defined to measure strain and stress, these models can be used either for standard and special measurements i.e. high-temperature, or for measurements in radiation field. Each part of the strain uncertainty and stress is analyzed from the point of view of a size of uncertainty and a form of probability of the function that strain and stress can adopt. The maximum focus was dedicated to the mistakes influencing measured strain like strain gage properties, installation and operating influences, external influences, time effects and the influence of the measured object. There are two mistakes influencing the stress described and analyzed in the thesis, the mistake of the Young’s modulus of elasticity and the mistake of the Poisson’s ratio. The thesis is conceived as a complex of information related to the measurement uncertainties using the resistance strain gages and methods of defining the measurement uncertainty in a way that the experimenter can apply the gained info and methods in the required measurements. The final chapters give representative examples to define measurement uncertainties for uniaxial and biaxial stress applying GUF and MMC method. The thesis also includes the experiment that compares measured values of strain, stress and measurement uncertainties, using several different types of strain gages at different temperatures, with theoretical calculation of strain and with stress. The experiment was carried out using the displacement sensor that works on an elementary principle of bending load.
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Measurements of the stress in the turbine spiral casing using the strain gauges
Dokoupil, Pavel ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The Master‘s thesis is focused on measuring of the stress in the spiral case of water turbine using the strain gauges measurement. It contains the theoretical and the practical part. The theoretical part includes a description of theoretical background (basic mechanics, measurement and evaluation, strain gauges, pressure measurement, uncertainty of measurement). One of the chapters describes Water Power Plant Lipno nad Vltavou (history of power plant, issues and the history of measurement). The practical part contains a theoretical calculation of measurement uncertainty and measuring of stress on spiral case Francis turbine at Water Power Plant Lipno I (Unit TG2). Measurement was made before and after overhaul. There are described technical data of spiral cases, description of measurement, results of measuring of strain and stress including comparison with the pressure in spiral case and calculation of uncertainties of measurement.
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Geodetic monitoring of the tubosider in Liberec under the ski slope F10
Buchar, Ondřej ; Jarůšek, Ladislav (referee) ; Kratochvíl, Richard (advisor)
This thesis describes a geodetic monitoring of a deformed steel structure tubosider in Liberec. There have been made periodic measurements of displacements and deformations of the object since 2015. Various interventions have been made in order to ensure a stability of the tunnel, which are also evaluated in this thesis. The results are graphs that describes shifts of the highest points in the tunnel. These values are further used by structural engineers and architects to suggest a solution.
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Possibilities of the Tensile Test
Nevřivý, David ; Harant, Martin (referee) ; Řiháček, Jan (advisor)
The Bachelor’s thesis deals with the possibilities of tensile testing, the parameters of the test specimens, testing machines and the equipment which can be used in this test. Based on the literature review, the thesis explains the test principle, the measurement process and the strain and stress characteristics detected by the test. The thesis then focuses on the test specimens, their geometry, the method of their sampling and gripping into the machine. When describing the machines and equipment used in tensile testing, the thesis explains the functionality of these and their different types. The work also covers special types of tensile tests, namely those using elevated temperature, high-speed deformation, and cyclic or multiaxial stress. The final part of the thesis examines the current trend of evaluating the tensile test using 3D optical measurement systems
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Determination of masonry modulus of elasticity in the direction of bed joints
Kuchař, Martin ; Klusáček, Ladislav (referee) ; Terzijski, Ivailo (advisor)
The determination of strain properties of masonry in the direction parallel to bed joints is a fundamental pre-requisite for designing structures, where masonry is subjected to horizontal stresses (e. g. strengthening with prestressing). The diploma thesis summarized techniques of determination of masonry modulus of elasticity presented in available literature. The goal is to suggest suitable methodology of determination of masonry modulus in direction parallel to the bed joints. In the practical part of the diploma thesis is that methodology verified by experimental test and results of tests are analyzed and discussed.
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Analytical model of composite cantilever with SMART layer
Dostal, Vojtěch ; Ševeček, Oldřich (referee) ; Majer, Zdeněk (advisor)
This bachelor's thesis deals with analytical modelling of composite cantilever with smart layer. The structure is based on the real piezoelectric generator, which is a solid cantilever beam with a layer of piezoelectric material attached to its bottom and top. The first part of this bachelor's thesis summarizes the knowledge of the energy harvesting, the process under which harvesting of electric energy from the piezoelectric generator belongs. Some piezoelectric materials are mentioned and described afterwards. At first, analytical modelling is implemented on the homogeneous cantilever beam. Then, the relations for required characteristics are derived for laminate structure, which is structurally similar to the piezoelectric generator. One chosen parameter will be changeable. Due to the ties of relations, the required characteristics will change as well, which are for the piezoelectric generator strain and deflection.
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