Identification of Replica Modes in Integrally Bladed Rotor
Effects on structure designs on free vibrations of integrated bladed rotor (IBR) have been conducted in this research through finite element simulations. Migration of natural frequencies is characterized through parameter studies considering changes of blade angle and blade thickness on an underlying uniform axis-symmetric rotor. Recurring coupled repeated doublet modes, defined as replica modes, has been observed in this study by characterizing blade’s vibrations in-phase or out-of-phase to disk’s vibrations. Veering and cluster of replica modes’ natural frequencies are observed with respect to the blade design parameters. Fourier content for low frequency replica component is found to be sensitive and tunable to blade angle design, which has implications on forced response of spinning IBR in engineering applications.
R. N. Mubarak and J. Y. Chang, "Identification of Replica Modes in Integrally Bladed Rotor", Applied Mechanics and Materials, Vols. 110-116, pp. 2348-2353, 2012