Svjetlovodni senzor za mjerenje vibracija

master's thesis

• Title (english): Fibre-optic sensor for vibrations measurement
• Author: Bojan Igrec
• Mentor: Željko Tuković (mentor)
• Mentor: Smiljko Rudan (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2015-03-27, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Radom je obuhvaćen razvoj idejnog rješenja i prototipa svjetlovodnog senzora za mjerenje vibracija na osnovi zahtjeva iz projekta pod nazivom “Konstrukcija i izrada prototipa svjetlovodnog senzora za mjerenje vibracija za daljinski nadzor električnih strojeva velikih snaga” koji se provodi na Fakultetu elektrotehnike i računarstva (FER) u Zagrebu.
U prvom dijelu rada prikazane su teorijske osnove iz područja optike te su napravljena dva analitička proračuna optičkih značajki senzora u svrhu određivanja maksimalne dozvoljene amplitude pomaka vibrirajuće membrane kao ulaznog podataka u proračun mehaničkih vibracija. Potvrda ispravnosti analitičkih optičkih proračuna dobivena je numeričkom simulacijom tog problema u komercijalnom računalnom programu ZEMAX (licenca FER).
U sklopu rada razvijen je poseban programski kod u softverskom paketu MATLAB s ciljem optimizacije mehaničkih komponenti svjetlovodnog senzora. Kod se temelji na analitičkim matematičkim modelima, koji su također u okviru diplomskog rada detaljno razrađeni.
Na osnovi podataka iz optičkog proračuna provjereni su načini vibriranja više izvedbi senzora korištenjem razvijenog koda te su preliminarno optimirane dimenzije senzora. Provjera rezultata dobivenih MATLAB kodom učinjena je usporedbom s rezultatima dinamičke analize metodom konačnih elemenata u softverskom paketu FEMAP / NASTRAN za različita idejna rješenja. Temeljem provedenih analiza određene su optimalne dimenzije mehaničkih dijelova senzora.
Temeljem ukupnih dobivenih rezultata osmišljeno je konstrukcijsko rješenje te su propisani materijali i tehnologija izrade svih mehaničkih dijelova prototipa senzora uvažavajući ograničenja koja proizlaze iz područja primjene senzora te financijska ograničenja. U tekstu se nalazi detaljan opis konstrukcije uz priložene radioničke crteže. Prototip je izrađen tehnologijom 3D printanja i prikazan na kraju rada.
Na samom kraju ispitan je utjecaj otpora okolnog zraka na vibracije membrane primjenom računalne dinamike fluida (CFD).

Abstract (english)

This thesis deals with the conceptual design and prototype development of a fiber optic sensor for measuring vibrations. The requests and working conditions for this sensor are given in a project which is being carried out at the Faculty of Electrical Engineering and Computing (FER) in Zagreb, named “Designing and production of a fiber optic sensor for measuring vibrations in remote monitoring of high-powered electrical machinery”.
First part of the thesis shows theoretical basis of optical measurements and also consists of analytical calculations of sensor’s optical characteristics in order to determine the maximal allowable amplitude of membrane’s vibrations. The computed amplitude is then used as input data in further calculations of mechanical vibrations. In addition, numerical simulations of the problem carried out in commercial software package ZEMAX (licensed to FER) were used to confirm the accuracy of optical analytical calculations.
As part of the thesis, a specific program code was developed in MATLAB software package in order to optimize the mechanical components of fiber optic sensor. The developed program code is based on analytical mathematical models, which are also elaborated within this thesis.
Using the program code, various implementations of sensor and their different vibrating modes were examined on the basis of optical calculations data. Additionally, preliminary dimensions of the sensor were established at this stage. For several different conceptual designs, control of results obtained by the MATLAB code was done by comparing them with results of dynamic finite element analysis in FEMAP / NASTRAN software package. In regard to conducted analysis, optimal dimensions of sensor’s mechanical parts were determined.
A structural solution for the sensor was designed according to overall results. Materials and production technologies for all of prototype sensor’s mechanical parts were defined by taking into account financial constraints and the constraints arising from sensor’s area of application.
The paper contains a detailed description of the design and the accompanying manufacturing sheets and drawings. The prototype was made using 3D printing technology and its images can be seen in penultimate chapter of this paper.
Finally, effect of drag (from the surrounding air) on vibrations of the membrane was investigated using computational fluid dynamics (CFD).

• Keywords: vibracije; metoda konačnih elemenata; mjerenje vibracija; optika; optička vlakna; senzori; frekventna analiza konstrukcija; konstruiranje
• Keywords (english): vibrations; finite element analysis; vibration measurement; optics; fiber optics; sensors; frequency analysis of structures; design
• Language: croatian
• URN:NBN: urn:nbn:hr:235:553499
• Study programme: Title: Mechanical Engineering; 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: 2019-05-27 12:54:38