NONLINEAR DYNAMIC CHARACTERISTIC ANALYSIS OF ARTICULATED TOWER PLATFORM IN THE DEEP WATER

The nonlinear dynamics characteristic of articulated tower platform (ATP) subjected to waves and current loads is studied. The units on the top of ATP is simplified into one concentrated mass. The tower and buoyancy cabinet are simplified into a uniform rigid bar. The model for ATP is put forward for dynamics analysis. Considering current and wave loads, hydrodynamic force is evaluated at the instantaneous position for the ATP by Morison formula, the highly nonlinear motion equation is established by Lagrange principle. The super-harmonic resonance and chaos motion of ATP are investigated using numerical method with wave loads and combined wave-current loads considered separately. The results show that super-harmonic resonance motion response of ATP increases under combined wave-current loads, and chaos motion occurs under high frequency and big amplitude wave excitation.