深水吊缆非线性垂向运动响应分析

Analysis of the Nonlinear Heave Motion Responses of Hoisting Rope in Deepwater

针对深水吊装过程中吊缆及吊载在外部扰动作用下的运动幅值较大,运动特性呈现较强的非线性问题,提出基于Hamilton原理求解吊缆非线性运动响应的方法,建立吊缆的非线性运动方程,采用有限差分方法进行求解,与文献的试验值比较,结果吻合较好,验证求解方法的准确性和可靠性。以4 500 m缆长为例,对不同吊缆上端激励周期下吊缆不同位置处的缆张力、垂向位移进行计算分析,结果表明,当吊缆长度较大时,缆张力及吊缆垂向位移在整个吊缆内不是均匀分布的,缆张力及垂向位移的传播呈现明显的波动现象,且随着吊缆长度和上端激励周期的增加,波动的幅值及变化剧烈程度逐渐减小。

The method based on elastic wave theory for solving nonlinear motion response was proposed to study deepwater hoist cable nonlinear motion characteristics and mechanical characteristics,and the nonlinear equations using the finite difference method to solve of motion hoist cable was established. The results were compared with the experimental ones in the literature to verify the accuracy and reliability of the solution method. Takibf the 4 500 m cable as example,the different incentive period under the upper hoist cable hoist cable tension cables and vertical displacement at different positions was calculated,the results showed that for a large hoist cable length,the cable tension and cables vertical displacement throughout the hoist cable is not evenly distributed,and the dissemination and vertical displacement of the cable tension showed significant fluctuation; with the increasing in the upper hoist cable lengths and incentive period,the amplitude fluctuations and changes in severity decreases.