Study on the Transient Dynamic Characteristics of TLP under Impact Load

Caused by the effect of transient impact load, the large-amplitude motions of platform main body may lead to mooring system's fracture and endanger platform's security. In this paper, numerical analysis method was employed to study the mooring characteristics and coupling dynamic response between tension leg platform main body and mooring system under different impact loads. The effect of three typical impact loads: sine pulse, triangular pulse and rectangular pulse were considered and the differential equation of motion was solved by self-compiling program. The effect of nonlinear damping, pulse shape, collision position, angle of attack, and the combined action of impact load and wave load on transient dynamic characteristics of platform were considered too. It was found that: under the three typical pulse loads, the computation results of surge and pitch response amplitude with nonlinear damping considered were both less than the results that nonlinear damping was ignored. The amplitude of platform motion responses was associated with the peak value of pulse. With the same pulse impulse, time histories of platform under the three pulse forms are basically in agreement with each other. Dynamical response of platform was affected by collision position and the angle of attacks. Affected by the combined action of impact load and stochastic wave load, large motion response of platform was mainly caused by impact load.