Hj. Kim et Ym. Cho, Dynamic characterization of noise and vibration transmission paths in linear cyclic systems (I) - Theory, KSME INT J, 14(10), 2000, pp. 1051-1060
Linear cyclic systems (LCS's) are a class of systems whose dynamic behavior
changes cyclically. Such cyclic behavior is ubiquitous in systems with fun
damentally repetitive motions (e. g. all rotating machinery). Yet, the know
ledge of the noise and vibration transmission paths in LCS's is quite limit
ed due to the time-varying nature of their dynamics. The first part of this
two-part paper derives a generic expression that describes how the noise a
nd/or vibration are transmitted between two (or multiple) locations in the
LCS's. An analysis via the Fourier series and Fourier transform(FT) plays a
major role in deriving this expression that turns out to be transfer funct
ion dependent upon the cycle position of the system. The cyclic nature of t
he LCS' transfer functions is shown to generate a series of amplitude modul
ated input signals whose carrier frequencies are harmonic multiples of the
LCS' fundamental frequency. Applicability of signal processing techniques u
sed in the linear time-invariant systems (LTIS's to the general LCSs is als
o discussed. Then, a criterion is proposed to determine how well a LCS can
be approximated as a LTIS. In Part IT, experimental validation of the analy
ses carried out in Part I is provided.