Abstract
The authors propose the utilization of a MIF (mode indicator function) to estimate modal damping ratios approximately. The accuracy and the effect of this method are examined to determine its feasibility for use in experimental modal parameter identification. MIF is a straight-forward function derived from FRFs, and indicates the existence of normal modes. MIF is generally used to indicate undamped natural frequencies, but not for other purposes. However, MIF can be used to estimate modal damping ratios roughly as well as to estimate undamped natural frequencies. The authors propose using of MIF to set the initial values of modal damping ratios as well as the values of natural frequencies in any modal parameter identification method in the frequency domain.
