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Model of composite cantilever with piezoelectric layer
Hons, Richard ; Kšica, Filip (referee) ; Hadaš, Zdeněk (advisor)
This thesis deals with the generating electrical energy from vibrations from piezoelectric composite cantilever beam. A review of the piezoelectric materials is made. Then the analytical model of piezoelectric cantilever beam is presented, then the influence of parameters is inves-tigated. Case study with theoretic design of parameters on the specific source of vibration is also provided. Last part is the extension of model for the variable width of layers at cantilever
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Design of load mechanism for laboratory model of rail track
Čech, Vít ; Lošák, Petr (referee) ; Kšica, Filip (advisor)
This bachelor thesis deals with the design of the loading of the similarity model of the track and the subsequent implementation and verification of the functionality of the designed device. The thesis is divided into three parts. In the first part of the thesis, the theoretical knowledge related to the effects acting on the track and a research of available methods and equipment that allow the investigation of the individual effects in a controlled laboratory environment are presented. The second part then focuses on the design and construction of the loading mechanism. This had to be designed in accordance with all the loading requirements of the model. The last part covers the testing of the designed loading mechanism and the results are compared with those from a real railway line and also with those measured during the original loading of the model using pneumatic pistons.
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Analysis of tuned mass damper
Jurečka, Martin ; Rubeš, Ondřej (referee) ; Kšica, Filip (advisor)
Complex mechanical structures are often exposed to external influences that can cause excessive vibrations, which can limit their ability to perform their function or affect operational safety. Tuned mass dampers, which are focus of this thesis are very often used to avoid such vibrations. The firts part of the thesis is focused on the research of the principle of tuned mass damper and its use in engineering practice. In the secound part obtained knowlage is used to create a mathematical model of the selected mechanical system and then to implement a suitably designed tuned mass damper to damp unwanted vibrations. Part of the work i also to build a real model of the tuned mass damper, which will demonstrate its function.
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Vibration analysis of single-engine aircraft
Loucký, Tomáš ; Hadaš, Zdeněk (referee) ; Kšica, Filip (advisor)
This bachelor’s thesis deals with the measurement and processing of data from a small single-engine aircraft, followed by analysis and evaluation regarding the overall structural load of the aircraft. The first part provides basic information about vibrations in general and their impact on an aircraft. It also focuses on methods and devices used for vibration measurement. The subsequent chapter describes the procedures of data processing in time, frequency, and time-frequency domains, as well as providing basics about statistical correlation and hypothesis testing. The next section of this thesis will work with the collected data from a test flight, utilizing the previously acquired knowledge to adjust and process all available signals. The goal will be to identify statistical correlations between sensor responses and aircraft maneuvers. Finally, conclusions will be drawn from the results regarding the applicability of sensors for determining the structural load during flight.
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Design of shaped springs for mechanical resonators
Ševčík, Jakub ; Kšica, Filip (referee) ; Hadaš, Zdeněk (advisor)
This bachelor's thesis deals with the design of a structural flexible member for mechanical resonators. Such designed member could find application as part of a vibration generator system. Vibration generators are used to power sensors where it is not easy to supply electrical energy, especially in railway transportation, specifically in monitoring the condition of tracks. This thesis provides an overview of current constructions of vibration generators, drawing inspiration for the subsequent design of the flexible component of the mechanical resonator. Subsequently, a suitable construction is created to ensure proper functioning of the resonator at frequencies ranging from 15 to 50 Hz. The design takes into account the manufacturing process using laser cutting and 3D printing. Two versions are created, where the first is suitable for laser cutting, and the second is suitable for 3D printing. The designed flexible components are then kinematically excited, and their maximum deflection at the resonant frequency is determined using the Ansys and Simulink software. Lastly, a spring suitable for 3D printing is manufactured. Its maximum deflection and the maximum generated power are determined. At an acceleration of 1 m/s2, the system achieves a deflection of 0.5 mm, and the generated power in this case is 0.035 mW. With increasing acceleration, the pover values can reach up to 0.8 mW.
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Analysis of spontaneous synchronization of coupled mechanical oscillators
Nečesal, Filip ; Hadaš, Zdeněk (referee) ; Kšica, Filip (advisor)
The work explains and describes the behavior of synchronization of two mechanical oscillators. This phenomenon is demonstrated on a physical model and compared with a computational model in several experiments. My motivation was that it is a fascinating phenomenon, and the problem is close to me because of the field I study. It was based on the knowledge gained during my previous studies. The first part of the bachelor thesis deals with the research on the synchronization of mechanical oscillators, the mathematical expression of individual types of oscillations, and their properties. The second part consists of a physic model of two pendulums on one base plate and a measurement of the system. The third part of the thesis contains a mathematical model, which was compared with the physical model in last part of the work.
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Design and fabrication of a vibration shaker with excitation by imbalance
Demura, Dominik ; Kšica, Filip (referee) ; Rubeš, Ondřej (advisor)
The topic of this thesis is the design and production of a vibrating table excited by unbalance. The main part of the work is the design of the table structure. The proposal depends on the basic requirements such as the maximum length of the beam, the natural frequency and the change in the natural frequency. The rest of the structure is adapted to these requirements and the dimensions of the beam. The next part of the work consists of the design of the exciter, which is based on the required values of acceleration, frequency of oscillation and weight of the exciter. In the work, the mechanical design and subsequently the control of the exciter was carried out. The main part of the control is the Arduino, which controls the entire system with the help of a program. At the end of the work, the entire experimental system is manufactured and tested. The measurement is performed using an accelerometer and a vibration energy harvester.
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Design of testing device for piezocomposite sensors
Zlámal, Radim ; Chalupa, Jan (referee) ; Kšica, Filip (advisor)
Presented bachelor’s thesis describes the design and the following assembly of a device used for testing MFC sensors. In the first part, fundamental theoretical findings regarding main properties of the sensors are listed, including their description and comparison with other piezoelectric materials. Available methods for measuring a response from the sensor are mentioned sequentially by means of applied stress (tension/compression, bending, torsion). The second part focuses on realization of the device based on the chosen physical principle for loading the tested specimen, to which the sensor is firmly attached. Construction of the device is designed and adjusted to meet the input requirements and boundary conditions for bending. Both hardware and software are selected to simulate the specific form of mechanical loading. The last part involvesstatic measurements of deformations on the specimen using a charge amplifier, as well as modelling of various dynamic cycles sensed by utilizing a load resistor. Voltage signal from the sensor is converted to strain, which is further transformed into deflection for measurement verification, and finally, the functionality of the entire device is evaluated.
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Methods for Design of Virtual Twin of a Dynamic System
Kšica, Filip ; Novotný, Tomáš (referee) ; Holub, Michal (referee) ; Hadaš, Zdeněk (advisor)
Over the last decade, digital twins and cyber-physical systems have been slowly developed from mere theoretical concepts to potent industrial applications in a large spectrum of areas, however, ambiguous understanding of the fundamentals significantly complicates the process of finding a general methodology necessary for their successful implementation. Therefore, one of the main goals of this thesis is a systematic study of these concepts and their main parts, followed by formulating a methodology that could lead to successful and effective industrial applications in the context of current projects. The key part in this effort falls to computational modelling and dynamic reduction of complex mechanical systems that comprise the digital part of a digital twin, including but not limited to the main structure but also sensing systems. These sensing systems serve as cyber-physical systems that fulfill the role of interactive links between the individual parts of a digital twin and are introduced in the last part of this thesis in the context of manufacturing industry, airspace, and railway industry, where they are used not only for condition and operational monitoring, but also provide large amount of accurate real-time data for structure health monitoring and predictive maintenance purposes.
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Design of an experimental system with excitation by imbalance
Demura, Dominik ; Kšica, Filip (referee) ; Rubeš, Ondřej (advisor)
The topic of this diploma thesis is the design and construction of an experimental system driven by imbalance. The main part of the work was to design the structure to meet certain requirements. The most important part of the structure is the beam. The mounting method and beam dimensions were calculated numerically and verified analytically using FEM. The rest of the structure was adapted to the dimensions of the beam. The next part of the work consists of the correct choice of vibration motor and its control. At the end of the work, the whole experimental system was manufactured and tested. We measure the vibrations using an accelerometer and then process the data into graphs.
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