Complex harmonic modal analysis of rotor systems


Complex harmonic analysis for rotor systems has been proposed from the strict complex modal analysis based upon Floquet theory. In this process the harmonic balance method is adopted, effectively associated with conventional eigenvalue analysis. Also, the harmonic coefficients equivalent to dFRFs in harmonic mode has been derived in practice. The modes are classified from identifying the modal characteristics, and the adaptation of harmonic balance method has been proven by comparing the results of the stability analyses from Floque theory and the eigen analysis. The modal features of each critical speed are depicted in quantitatively and qualitatively by showing that the strengths of each component of the harmonic coefficients are estimated from the order of magnitude analysis according to their harmonic patterns. This effectiveness has been verified by comparing with the numerical solutions.

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Corresponding author

Correspondence to Dong Ju Han.

Additional information

Recommended by Associate Editor Ohseop Song

Dong-Ju Han received his B.S. in Aeronautical and Mechanical Engineering from Hankuk Aviation College of Seoul, Korea in 1984; M.S., in Aero-Mechanical Engineering from KAIST, Seoul, Korea in 1986; and Ph.D. in Mechanical Engineering from KAIST, Daejeon, Korea in 2006. He is a professor in the Department of Aviation Maintenance Engineering at Kukdong University. His research interests are in rotor dynamics, vibration, fault detection and isolation, modeling and simulation of A/C engine control system.

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Han, D.J. Complex harmonic modal analysis of rotor systems. J Mech Sci Technol 29, 2735–2746 (2015).

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  • Critical speed
  • Directional frequency responses
  • Floquet theory
  • Harmonic modal analysis
  • Rotor systems
  • Stability