ON-OFF INTEMITTENEY PHENOMENA IN A PENDULUM WITH A RANDOMLY VIBRATINGSUSPENSION AXIS

We demonstrate that the excitation of noise-induced oscillations of a pendulum with a randomly vibrating suspension axis occurs via 'on-off intermittency'. The dependence of the mean duration of 'laminar' phase on the excess of the noise intensity over a Certain critical value is calculated analytically. These theoretical dependencies are confirmed by the results of numerical experiments. Further, we study the influe nce of an additional harmonic action. It is shown that the oscillation s are intensified if the frequency of this action is low, and suppress ed if the action frequency is high. It is interesting that the suppres sion of the oscillations, much like their excitation, occurs via 'on-o ff intermittency'. The dependence of the mean duration of 'laminar' ph ase on the action amplitude is obtained from numerical experiments. (C ) 1998 Elsevier Science Ltd. All rights reserved.