STATISTICAL ENERGY ANALYSIS OF MULTIPLE, NON-CONSERVATIVELY COUPLED SYSTEMS

In what follows, the analysis of Keane [1] for the energy flows around an arbitrary configuration of coupled multi-modal subsystems is exten ded to the case of non-conservative coupling. Here, the joints between any two subsystems are modelled by a spring and a damper, thus allowi ng for dissipation of energy to occur at the joint. The aim of this st udy is to give greater insight into the problem of energy flows throug h non-conservative couplings which has not been extensively discussed in the literature. Interest is focused on the effect of damping in the joints on the magnitudes of energy flows between, and energy levels i n, each subsystem. The model derived is used to demonstrate the well k nown fact that selecting the correct level of damping in the joints su rrounding a driven subsystem may cause a large percentage of the power input to the subsystem to be dissipated in these joints. This minimiz es the overall power dissipated within the subsystems and thus the sys tem total energy level. A Statistical Energy Analysis (SEA) model for non-conservatively coupled systems is then suggested, in which couplin g damping loss factors are introduced into the main SEA energy balance equations to account for the energy dissipation in the joints. This m odel is shown to be exactly correct for the limiting case of weak coup ling. Numerical examples which illustrate these various ideas are pres ented, with the use of parameters adopted in previous studies. (C) 199 6 Academic Press Limited