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Nonlinear Structural Identification Using a Multi-Harmonic Frequency Response Functions

Vahid Yaghoubi (Institutionen för tillämpad mekanik, Dynamik)
Göteborg : Chalmers University of Technology, 2013. - 74 s.
[Licentiatavhandling]

In industrial structural dynamics problems, linear FE-models commonly serve to represent the global structural behavior. However, when test data are available they often show evidence of nonlinear dynamic characteristics. In that case, an initial linear model may be judged insufficient in representing the dynamics of the structure. The causes of the non-linear characteristics may be local in nature whereas the major part of the structure is satisfactorily represented by linear descriptions. Although the initial model can serve as a good foundation, all physical properties required for representing the real structure with high fidelity are most likely not included in the initial model. Therefore, a set of parameterized candidate properties controlling the nonlinear effects have to be added. The selection of the candidates is a delicate task which must be based on insight into the physical processes that control the structure at hand. The focus of this thesis is on the selection of uncertain model parameters together with the forming of the objective function to be used for calibration. To give precise estimation of parameters in the presence of measurement noise, the objective function data have to be informative with respect to the selected parameters. Also, to get useful test data for calibration, the system stimuli need to be properly designed. A multi-harmonic stationary sinusoidal excitation is here considered since the corresponding steady-state responses at the different harmonic orders are shown to contain valuable information for the calibration process.

Nyckelord: Nonlinear structure, inverse problem, grey box system identification, finite element model updating, identifiability, Fisher information matrix, multi-harmonic frequency response function



Denna post skapades 2013-11-29. Senast ändrad 2016-04-15.
CPL Pubid: 187934

 

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Institutioner (Chalmers)

Institutionen för tillämpad mekanik, Dynamik

Ämnesområden

Fastkroppsmekanik

Chalmers infrastruktur

Relaterade publikationer

Inkluderade delarbeten:


Automated modal analysis based on frequency response function estimates


Locally Non-linear Model Calibration Using Multi Harmonic Responses: Applied on Ecole de Lyon Non-linear Benchmark Structure


Examination

Datum: 2013-12-11
Tid: 10:00
Lokal: EE, Hörsalsvägen 11
Opponent: Dr. Martin Magnevall

Ingår i serie

Technical report - Department of Applied Mechanics, Chalmers University of Technology, Göteborg, Sweden 2013:24