Equivalent mixing of experimental models in dynamic substructuring

Bregar, Tomaž (author), Boltežar, Miha (mentor), Čepon, Gregor (co-mentor)

Evaluation of structural dynamics is an essential step in the design of modern complex mechanical systems. The ever increasing demand on optimization of vibro-acoustic performance has led to numerous advancements in noise, vibration and harshness engineering in the past decade. One of the most promising frameworks is dynamic substructuring, within which complex dynamic systems can be analyzed by characterizing each subsystem separately. This work covers an experimental approach to frequency based substructuring and transfer path analysis. Through experimental modelling the real dynamic properties of each subsystem can be obtained directly, without the need for a complex numerical model. Several approaches to experimentally model an interface within frequency based substructuring are introduced. An expansion to virtual point transformation is presented, where directly measured rotation response is included in the transformation. An novel transformation method named the singular vector transformation is presented on a coupling and decoupling application. Furthermore, an approach to identifying a set of full-field frequency response functions based on system equivalent model mixing is presented. Finally, an application of component-based transfer path analysis is presented on the source characterization of an electric motor. The main limitations and advantages of each methodology are outlined. Based on the provided observations, both frequency based substructuring and transfer path analysis can be an integral part of the development process.

• Language: English
• Keywords: strukturna dinamika, eksperimentalno modeliranje, podstrukturiranje v frekvenčni domeni, analiza prenosnih poti, transformacija virtualne točke, transformacija singularnih vektorjev
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [T. Bregar]
• Year: 2021
• Number of pages: XXVIII, 130 str.
• PID: 20.500.12556/RUL-127325
• UDC: 531.391:534.2:004.925(043.3)
• COBISS.SI-ID: 65652739
• Publication date in RUL: 03.06.2021

Secondary language

• Language: Slovenian
• Title: Ekvivalentno mešanje eksperimentalnih modelov v dinamiki podstruktu

Abstract

Vrednotenje strukturne dinamike je bistven korak pri načrtovanju sodobnih mehanskih sistemov. Vedno večje povpraševanje k optimizaciji vibro-akustičnih karakteristik je v zadnjem desetletju privedlo do številnih napredkov na področju obvladovanja hrupa in vibracij. Eno najbolj obetavnih področij je dinamika podstruktur, ki omogoča analizo kompleksnih dinamskih sistemov z dekompozicijo na manjše podsisteme. Doktorska naloga obravnava frekvenčno podstrukturiranje in analize prenosnih poti na eksperimentalno pridobljenih dinamskih modelih. Z eksperimentalnim modeliranjem posameznega podsistema lahko neposredno pridobimo resnične dinamske lastnosti, brez potrebe po zapletenih numeričnih modelih. Raziskanih je več pristopov eksperimentalnega modeliranja povezave znotraj frekvenčnega podstrukturiranja. Predstavljena je razširitev transformacije virtualne točke z direktno izmerjenim rotacijskim odzivom. Predstavljena je nova metoda transformacije singularnih vektorjev na aplikaciji sklapljanja in razsklapljanja. Predstavljena je tudi predikcija polnega polja frekvenčno prenosnih funkcij iz šumnih meritev hitre kamere na podlagi metode kombiniranja ekvivalentnih modelov. Nazadnje pa je obravnavana karakterizacija izvora elektromotorja na podlagi analize prenosnih poti. Opisane so glavne omejitve in prednosti posamezne metodologije. Na podlagi predstavljenih rezultatov sta lahko tako podstrukturiranje kot analiza prenosnih poti, ob pravilni uporabi, sestavni del razvojnega procesa.

• Keywords: structural dynamics, experimental modelling, frequency based substructuring, transfer path analysis, virtual point transformation, singular vector transformation