Resonant Response Characteristics of a Group of Blades. (3rd Report. Methodologies for Research on "Coupled Natural Vibration of Axial Deflection and Torsion of a Finite Group of Blades" and "its Resonant Response Characteristics").

Abstract

In a continuation of our research on resonant response characteristics of a group of blades, other aspects of which were reported by sister papers (1), (2) and (3), coupled vibrations of axial deflection and torsion of a group of blades are thoroughly investigated in the present work. From the results, we explicity and quantitatively determine the resonant stress increasing and decreasing effects in such coupled vibrations and we provide a theoretical explanation of the cause of those effects. Our whole research, consisting of two series of studies, that is, the former study(1)∼(3)on uncoupled ibration of only tangential deflection and the present on coupled vibration of axial deflection and torsion, is aimed at elucidating the essence of resonant stress increasing and decreasing effects in a group of turbine blades; it should be a contribution to rotating machine's dynamics. In this paper, the first of the new series, methodologies are presented for the investigation on the resonant response characteristics of such coupled vibration, comparing with the methodologies adopted in sister papers(1), (2)and(3).