ANALYSIS OF BIFURCATED SUPERSTRUCTURE OF NONLINEAR OCEAN SYSTEM

An intricate universal superstructure in bifurcation sets and routes t o chaos of a nonlinear moored ocean system subjected to monochromatic wave excitations are investigated analytically and demonstrated numeri cally in detail herein. System nonlinearities include complex geometri c restoring force and coupled fluid-system exciting forces. Primary an d secondary resonance regions are identified by employing variational analysis techniques for local stability. Tangent and periodic doubling bifurcations are examined to reveal the underlying intricate superstr ucture. Numerical results of this complex system uncover a steady-stat e superstructure in the bifurcation sets that exhibit a similar bifurc ation pattern of coexisting solutions in the subharmonic, ultraharmoni c, and ultrasubharmonic domains. Within this superstructure it is illu strated that strange attractors appear when a period doubling sequence is infinite, and when abrupt changes in the size of an attractor occu r near tangent bifurcations.