engleski

Time domain methods and observer approach for modal parameter identification

Linear time invariant (LTI) systems like linear elastic structures are characterized by modal parameters i.e. natural frequencies, natural modes and modal damping. For the given mathematical models there are number of well established procedures that calculate modal parameters (Ljung, 2006, Ewins, 2000). When the structure is given as real system, experiment is employed to detect modal parameters. The experiment comprises excitation of the structure, data acquisition, data processing and finally modal parameters extraction. During last decades a number of very sophisticated methods for modal parameters detection have been and still are being developed (Zhou, 2008). All these methods can be divided in two groups: frequency domain and time domain methods. The frequency domain methods are typically based on modal parameters detection from the frequency response functions (FRF) while time domain methods typically rely on impulse response function. So we can conclude that the most of the methods detect the modal parameters in two steps: FRF or impulse response function has to be calculated first and then modal parameter detection techniques applied.

time domain method; modal parameters identification; impulse response function

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