Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Modal Parameters Identification Methods based on output-only
Submission Author:
Jacqueline Terre de Souza , PR , Brazil
Co-Authors:
Nilson Barbieri, Jacqueline Terre de Souza
Presenter: Jacqueline Terre de Souza
doi://10.26678/ABCM.COBEM2017.COB17-2347
Abstract
Modal Analysis is an experimental technique to characterize the dynamic properties of a vibrating system, these properties are known as modal parameters. The most important modal parameters are: resonance frequency, mode shapes and damping ratio [1]. Experimental modal analysis (EMA) identifies the dynamic response from measurements of the applied force and the vibration response. It is a classic input-output method where input need to be applied, controlled and measured. The output (vibration response) also needs to be measured [2]. Operational modal analysis (OMA), aims at identifying the modal properties of a structure using ‘output-only’ vibration data under ambient conditions [3]. Other reason for choosing to apply OMA is that it does not interfere with operational use of a structure, and the input loads do not need to be known [4]. High economy and feasibility in data collection is a major advantage [3]. In the deterministic realization the input data are known previously and controlled. A stochastic realization problem is when we do not know the input data and “output-only” data are used to find the modal parameters. Identifying modal properties without input information is theoretically more involved. Results have much higher variability/uncertainty and sensitivity to algorithmic parameters compared to their counterparts identified with free or forced (known input) vibration data [3].
Keywords
modal analysis, Modal Parameters, Identification Methods, OMA
