A new method for line spectra reduction similar to generalized synchronization of chaos

Line spectra in the radiated noise of marine vessels are the most visible signs, which can be detected, tracked and identified by enemyʹs passive sonar, and hence it is of great significance to reduce the line spectra for improving the acoustic stealth of marine vessels. In this paper, a driving parameter scheme using an external chaotic signal to drive a nonlinear vibration isolation system (VIS) of onboard machinery is presented to make the chaotic motion in the nonlinear VIS persistent, which is similar to generalized synchronization of chaos in some sense. In this way, the line spectra in the radiated noise can be reduced effectively because the response spectrum of a chaotic system under harmonic excitations is a continuous and reduced one. Numerical simulations are carried out and the results confirm the effectiveness of this method. The maximum conditional Lyapunov exponent is calculated numerically and its negative value indicates the stability of this driving parameter control scheme.