Utjecaj prigušenja zraka na efikasnost uređaja za žetvu energije vibracija

master's thesis

• Title (english): The influence of the air-gap damping effect on the efficiency of a vibration energy harvester
• Author: Mislav Vučinić
• Mentor: Neven Alujević (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2022-12-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

U ovom diplomskome radu analiziran je utjecaj vakuuma na koeficijent prigušenja i efikasnost uređaja za žetvu vibracija. Također, konstruiran je i karakteriziran sustav koji se sastoji od primarne strukture sa integriranim uređajem za žetvu vibracija koji ujedno služi i kao dinamički prigušivač vibracija. Mehanički dijelovi uređaja konstruirani su tako da budu pogodni za izradu tehnologijom 3D ispisa i to upotrebom 3D pisača, Prusa i3 MK3S. Uređaj je tako konstruiran da se unutrašnjost uređaja za žetvu vibracija može evakuirati korištenjem standardne vakuum pumpe kakva se koristi za servisiranje klima uređaja. Također konstrukcija je osmišljena na način da se dinamički odziv može dobro aproksimirati matematičkim modelom za linearni vibracijski sustav s dva stupnja slobode gibanja. To je postignuto korištenjem računalnih CAD/CAM alata za modeliranje i konstruiranje, kao i alata za analizu slobodnih vibracija mehaničkih sustava s raspodijeljenim parametrima metodom konačnih elemenata. Nadalje, uređaj je osmišljen na način da se za pretvorbu mehaničke energije u električnu koriste dva paralelno povezana elektrodinamička pretvornika PBA Systems CVC40–HF–6.5. Konačna konstrukcija je izrađena, sklopljena a zatim karakterizirana mjerenjem prijenosne funkcije na slobodno ovješenom uređaju između napona narinutog na terminale zavojnice jednog od pretvornika i napona induciranog na terminalima zavojnice drugog pretvornika. Mjerenjima je utvrđen utjecaj vakuuma na prigušenje unutar elektrodinamičkih pretvornika. Analitički su definirani optimalni parametri sustava sa ciljem maksimiziranja razvijene korisne snage i minimiziranja vibracija primarne strukture u slučaju sa ili bez vakuuma unutar uređaja za žetvu vibracija. Usporedbom korisnih snaga za oba slučaja definiran je utjecaj vakuuma na efikasnost uređaja.

Abstract (english)

In this thesis the influence of vacuum on the damping coefficient and efficiency of a vibration energy harvester is analysed. Also, this thesis deals with design and characterization of a primary structure with integrated vibration energy harvester which also acts as a dynamic vibration absorber. Mechanical parts of the device are designed in such a way that they can be manufactured using 3D printing technology, in particular, using Prusa i3 MK3S 3D printer. The structure is designed in such a way that it can be evacuated using a standard vacuum pump that is ordinarily used for air conditioning systems maintenance. Also, the dynamic response of the structure is approximated using a mathematical model assuming a two degrees of freedom linear mechanical system. This is achieved by using CAD/CAM tools for modelling of the mechanical parts of the device, and Finite Element Method (FEM) tools for the free vibration analysis of the flexible mechanical parts of the device. Furthermore, the harvester has been designed so that two electrodynamic transducers PBA Systems CVC40–HF–6.5 mounted in parallel can be used for the transduction of mechanical into electrical energy. The final design has been manufactured, assembled and characterized by measuring the frequency response function between the voltage applied to the electrical terminals of one of the two transducers and the voltage induced on the electrical terminals of the other transducer. Effect of vacuum on the damping coefficient of the two electrodynamic transducers has been defined experimentally. Optimal parameters of the system were found analytically which maximise useful power output and minimize the primary structure vibrations in cases with and without vacuum inside the energy harvester. Effect of vacuum on the energy conversion efficiency was evaluated by comparing the harvested energy in the case when the air is present in the energy harvester interior to the harvested energy in the case when its interior is evacuated.

• Keywords: Primarna struktura; uređaj za žetvu vibracija; dinamički prigušivač vibracija; 3D ispis; vakuum pumpa; eksperimentalno mjerenje; koeficijent prigušenja; efikasnost
• Keywords (english): Primary structure; vibration energy harvester; dynamic vibration absorber; 3D printing; vacuum pump; experimental measurements; damping coefficient; efficiency
• Language: croatian
• URN:NBN: urn:nbn:hr:235:660441
• Study programme: Title: Mechanical Engineering; specializations in: Design, Process and Energy Engineering, Production Engineering, Engineering Modelling and Computer Simulation, Marine Engineering, Industrial Engineering and Management, Materials Engineering, Mechatronics and Robotics, Autonomous Systems; Course: Engineering Modelling and Computer Simulation; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-12-02 09:09:01