Karakterizacija modalnih parametrov pri obratovanju sistema z metodo pseudo sil

magistrsko delo magistrskega študijskega programa II. stopnje Strojništvo

Tim Vrtač (Author), Gregor Čepon (Mentor), Miha Boltežar (Co-mentor)

Abstract

Osnovo za karakterizacijo modalnih parametrov predstavljajo frekvenčne prenosne funkcije, ki podajajo povezavo med odzivom in vzbujevalno silo v izbranih točkah strukture. Določanje frekvenčno prenosnih funkcij tekom obratovanja je še posebej težavno, ker navadno ni moč neposredno določiti velikosti in lokacije delovanja vzbujevalne sile. S tega vidika se metode identifikacije navadno osredotočajo le na meritve prenosnosti oz. preko strukturnih modifikacij na rekonstrukcijo frekvenčno prenosnih funkcij. V tem delu je predstavljen razvoj nove metode za identifikacijo frekvenčno prenosnih funkcij, ki preko določitve t. i. pseudo sil omogoča posredno identifikacijo obratovalnih obremenitev. Ker je za popis realnih obratovalnih parametrov navadno potrebnih več pseudo sil je bila za identifikacijo frekvenčno prenosnih funkcij uporabljena metoda MIMO (ang. Multi-Input Multi-Output). Dodatno smo uporabili razcep na singularne vrednosti (SVD) za preverjanje medsebojnih odvisnosti pseudo sil in operacijske deformacijske oblike (ODS) za usklajevanje različnih sklopov meritev. Na ta način nam je uspelo razviti postopek, ki omogoča določanje frekvenčno prenosnih funkcij tekom obratovanja sistema brez kakršnih koli strukturnih modifikacij. Učinkovitost in natančnost postopka je bila verificirana na numeričnem primeru ter validirana na osnovi eksperimenta.

Keywords

magistrske naloge;frekvenčne prenosne funkcije;obratovalne obremenitve;frekvenčno podstrukturiranje;analiza prenosnosti poti;metoda pseudo sil;MIMO metoda;

Data

Language:	Slovenian
Year of publishing:	2021
Typology:	2.09 - Master's Thesis
Organization:	UL FS - Faculty of Mechanical Engineering
Publisher:	[T. Vrtač]
UDC:	519.6:531.2:53.08(043.2)
COBISS:	78195971
Views:	543
Downloads:	114
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Characterization of modal parameters during system operation using pseudo force method
Secondary abstract:	Frequency response functions are the basis for the characterization of modal parameters, which connect system response to the excitation force at the selected points of the structure. Their determination during system operation can be difficult due to the inability to determine the magnitude and the location of excitation force. From this point of view, the methods for identification usually focus on the measurement of transmissibility or the reconstruction of frequency response function through structural modifications. In this work, a new method for frequency response function identification is introduced. By application of so-called pseudo force method, the new formulation enables the indirect identification of operational loads. As more than one pseudo force is usually needed to fully reproduce operational loads the MIMO (Eng. Multi-Input Multi-Output) method was used for the frequency response function identification. Additionally, the singular value decomposition is proposed to evaluate the dependencies between the pseudo forces and the operating deflection shapes (ODS) to ensure correct magnitudes and phases between different measurement sets. This enabled to design a procedure for the determination of the frequency response functions during system operation without any structural modifications. The efficiency and accuracy of the procedure were verified by the numerical example and validated by the experiment.
Secondary keywords:	master thesis;frequency response functions;operational loads;frequency-based substructuring;transfer path analysis;pseudo force method;MIMO method;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. Ljubljana, Fak. za strojništvo
Pages:	XXIV, 60 str.
ID:	13285867