Modal parameter identification of structures and rotating machine by adaptative filter / Identificação de parametros modais de estruturas e maquinas rotativas atraves da filtragem adaptativa

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

This work investigates the use of adaptive filters for parameter identification. Although adaptive algorithms are still rarely utilized in the mechanical engineering field, the recursive least square and recursive least square with QR decomposition methods can be implemented based on the second ordinary differential equations in order to characterize the modal parameters. With this in mind, this study seeks to understand structure and rotating machine dynamics. In many case, when performing field analysis, it is common to face the situation where it is impossible to stop some critical equipments. In this case, all measurements performed on these equipments and the neighboring structures will be corrupted by the harmonic noise generated during the operation of these machines. In this direction, the proposed methodology contributes to the solution of this problem in two distinct ways. First, this approach can handle with measurements coming from experimental modal analysis of structures even when they are corrupted by harmonic noise. The only information needed is the instantaneous frequency of this noise. For rotor dynamics, on the other hand, the methodology allows the identification of the modal parameters of the system while this is operating in non-stationary condition, for example, during start-up or shut-down. In this case the measurement of the rotational speed is also required. The results suggest that the natural frequency and the vibration modes are precisely estimated, even for time varying systems. The numerical and experimental analysis reveals difficulty on the identification of the damping factor, especially when the signal is poorly conditioned. Amongst the nice characteristics of these methods, maybe one of the most interesting is the possibility to extract modal parameters in realtime

ASSUNTO(S)

filtros adaptativos rotor analise modal adaptative filter estimativa de parametro parameter identification modal analysis rotores

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