National Repository of Grey Literature 38 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Measurement of dry friction coefficient
Meško, Marek ; Brablc, Martin (referee) ; Rubeš, Ondřej (advisor)
This thesis describes modelling of dry friction and determining appropriate friction coefficients. The theoretical part of the thesis is devoted to the basic models of dry friction. The aim of the practical part of this thesis is to create devices for measuring friction coefficients and subsequently to measure the corresponding friction coefficients using these devices.
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.
Analysis of excited oscillation of non-linear energy harvester on shaker
Jaroš, Vojtěch ; Rubeš, Ondřej (referee) ; Hadaš, Zdeněk (advisor)
This thesis focuses on controlling the acceleration amplitude of a vibration exciter, that tests either linear or nonlinear spring-hardening harvesters. The thesis includes searches for vibration exciters. It also deals with control research and control simulations of vibrating exciter during vibration testing in the Matlab Simulink. At the end of the thesis, simulations of control of the vibration exciter, which tests linear and non-linear harvesters are presented
Vibration energy harvester influence on vibration base
Nagy, Andrej ; Bajer, Jan (referee) ; Rubeš, Ondřej (advisor)
The goal of this thesis is to describe the impact of the energy harvester on the vibrating base, while also showing the basic aspects of energy harvesting. We first describe the issue on the research side, where we explain the concept and real use of energy harvesters, we show their basic construction with pictures of models and graphs from experiments showing their behavior. We also show how energy harvesters can be optimized and improved. At the end of the research part, we describe how the energy harvester can influence the deviation of the base, and therefore why it is important to model the system with a feedback impact on the base. In the practical part, we derive a mathematical model using Lagrange equations of the second kind, which we subsequently use for numerical and analytical solutions. In the final part of the work, we analyze the influence of individual parameters of the energy harvester on the output power and base deviation with the help of Matlab and Simulink.
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.
Magnetic spring design for vibration energy harvester
Kobík, Martin ; Sosna, Petr (referee) ; Rubeš, Ondřej (advisor)
The thesis is concerned with a design of a magnetic spring which could be used in an energy harvester. A parametric computational model is created, which allows to simulate the spring‘s force-displacement relationship with chosen parametres, such as the position and dimensions of the magnets. Furthermore two coefficients are defined for evaluating the force-displacement relationship – the coefficient of nonlinearity and the coeficient of linearized stiffness. The coefficients are further used in the analysis of the effect of the change of parameters on the force-displacement relationship. After the analysis, specific parameters are chosen for the construction of demonstration device. The computational model is finally validated by the demonstration device.
Vibration energy harvester as a tuned mass damper
Novák, David ; Machů, Zdeněk (referee) ; Rubeš, Ondřej (advisor)
This bachelor thesis it's about vibration energy harvester as a tuned mass damper the design of a vibration generator as a dynamic vibration damper.The work contains a research part, which examines the methods of damping mechanical systems and the influence of the vibrating generator on the vibrating base. Based on this knowledge, equations of motion were derived for the design of the model in the SIMULINK program, where we optimized the parameters for maximizing the obtained electrical power and maximizing the damping effect.
Design of planar electromagnetic generator for sea drifter
Almáši, Matej ; Rubeš, Ondřej (referee) ; Hadaš, Zdeněk (advisor)
Unfixed buoys are an important part of sea and sea current monitoring. It is important that these buoys display a great amount of self-sufficiency. Electronic components of the buoy are conventionally powered by batteries, however there is an attempt to replace them with more self-sufficient sources that utilize energy from sea waves. For this purpose, so called “energy harvesters” that utilize electro-mechanic conversion are being developed. This thesis is focused on raising the power output of an energy harvester that is currently being developed at the FME BUT by finding the ideal parameters of the generating coil. An electro-mechanic model was developed which was then utilized to perform a sensitivity analysis. The result of the analysis was a set of coil parameters that resulted in the greatest power output. Subsequently, a coil prototype was manufactured, and the power output was measured experimentally. The root mean square value of the generated power was PRMS = 152.7 µW, which less than expected by the used model, however the coil winding didn’t fill up the space dedicated to it to the expected degree.
Analog front-end for piezoelectric sensor
Wich, Petr ; Chalupa, Jan (referee) ; Rubeš, Ondřej (advisor)
The purpose of the thesis was to describe and compare the properties of analog front end for piezoelectric sensor circuits. First, the basic circuit was described, then the design and implementation of the current-to-voltage converter, the charge amplifier and the circuit for voltage sensors on the parallel resistor. There was construct measuring system for measurement of the circuits. At last was made measurement of the created circuits, results were compared with each other, and their properties described.

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