Dynamics of a moored barge under periodic and randomly disturbed excitation

Offshore systems often exhibit distinctly nonlinear phenomena. Even when excited periodically by waves, they show responses ranging from harmonic or subharmonic to chaotic motion. Depending on the system's parameters, these different types of responses can be coexisting, which makes the initial conditions crucial for the steady state response. Here, the case of a moored barge is considered. The excitation is assumed to have a periodic component and an additive disturbance modelled as white noise. The response of this system, which shows multiple attractors for purely periodic forcing, reveals some similarities but also fundamental differences for the disturbed forcing.