考虑下沉运动情况下的张力腿平台耦合动力响应

Dynamical Coupled Response of Tension Leg Platform Considering Set-down Motion

考虑张力腿平台的六个自由度运动,分析平台本体纵荡、横荡和首摇与下沉运动的关系,推导了非线性恢复刚度矩阵,建立非线性运动方程。基于Airy波波浪理论,在不同波高作用下,计算张力腿平台的运动响应,得到平台运动的时间历程和频谱特性。将基于新推导的刚度矩阵的计算结果与A.Jain刚度矩阵得到的计算结果进行了比较分析,表明平台的下沉运动导致平台垂荡运动响应明显增大。在垂荡运动中包含了波频和倍频超谐运动成分,纵荡、横荡和首摇对于下沉具有重要影响。

A new nonlinear restoring stiffness matrix of the tension leg platform（TLP） is derived, considering the coupled effect of the horizontal motions（surge, sway and yaw） and the set-down motion. Differential equations of TLP with six degrees of freedom are derived. Based on Airy＇s wave theory, nonlinear dynamicresponse of TLP on the wave height is acquired in both time and frequency domains, and compared with that from conventional restoring stiffness. Through the numerical calculation, it is shown that the set-down motion will strengthen the heave motion significantly. The response to the wave and the super-harmonic response at the multiple frequencies are included in the heave motion. Surge, sway and yaw motions have important influences on the set-down motion.