Bifurcations of subharmonics and chaotic motions of articulated towers

Abstract

The dynamic responses of articulated towers, subjected to regular waves and large motions, are computed numerically using the governing nonlinear differential equations. In certain frequency and system parameter ranges, the motions of the towers are found to exhibit subharmonics and chaotic behaviour which are identified to be the type of intermittency with random alternations of chaotic and regular behaviour in time evolution. The identification, characterization and evaluation of the chaotic motions are performed numerically by studying the discrete trajectories and Poincaré points of the responses. Such chaotic behaviour, if with significant magnitude, can make the responses of the deterministic system random and unpredictable in a practical sense, because the system is extremely sensitive to the initial conditions assumed. © 1988.