敷设过程中海底电缆面内力学行为的理论分析

Theoretical analysis of in-plane mechanical behavior of submarine cables during laying operations

为了研究海底电缆敷设过程中电缆的形态、受力特性,考虑电缆张力、自重及海水浮力耦合作用,提出电缆敷设过程中海洋深度方向二维平面内力学行为的半解析近似分析方法。利用牛顿运动定律建立海底电缆微段的力学平衡方程,即微分方程组;考虑电缆敷设过程中海底电缆切角、曲线形状和张力变化,分析海底电缆面内力学行为。通过数值分析可以得出:敷设过程中电缆的张力沿着海深分布几乎呈线性,与海底电缆自重、船速和初始张力相比,电缆的放张速度对海底电缆受力的影响较小,且可以忽略不计。

In order to research the morphology and mechanical properties of submarine cable during laying operations,a semi analytical approximation of a two dimensional in plane mechanical behavior along ocean depth during laying operations is presented,with considering the coupling effect of submarine cable’s tension,self weight and the sea buoyancy.In the analysis,the mechanics equilibrium equations,that is a set of non linear differential equations of a short section of submarine cable are established with using Newton’s laws of motion,which is comprehensively considering submarine cable elevation angle,configuration and tension change during laying operations and analyzing in plane mechanical behavior of submarine cables.Through numerical simulation calculation in numerical examples,the submarine cable’s tension almost varies linearly with the water depth and the effect of pay out rate on submarine cables during laying operations relative to submarine cable self weight,cable ship velocity,and the pretension is negligible.