海上浮圈结构在规则波下的频域水弹性响应

Frequency Domain Hydroelastic Response of Offshore Floating Collars Under Regular Waves

运用水弹性理论分析浮圈结构在波浪作用下的弹性变形,并考察浮圈尺寸、吃水、弹性模量及环境参数对浮圈垂向变形幅值的影响。采用离散模块-梁单元(Discrete-Module-Beam,DMB)方法对浮圈进行水弹性分析。将浮圈离散为若干个刚性子模块,运用多刚体水动力学理论计算作用于浮圈的水动力载荷,并用曲梁理论计算浮圈结构的整体变形。结果表明:浮圈不同位置的垂向变形有明显差异,在波浪传播方向首尾两端的变形幅值明显大于中部,且这一特点随入射波频率的增加更加明显;在高频段浮圈的整体变形幅度随直径比和弹性模量的增加而减小;吃水对浮圈垂向变形幅值的影响相对较小,其主要作用体现在加剧了迎浪点垂向变形幅值曲线在高频段的振荡现象;水深变化对浮圈垂向变形的影响在不同位置和不同频率下呈现出差异性。

The hydroelastic theory is applied to analyze the elastic deformation of the floating collar under wave action.The effects of the floating collar's dimension,draught,elastic modulus,and wave conditions on the vertical displacement of the structure are investigated.The Discrete-Module-Beam(DMB)method is used to perform the hydroelastic analysis on the floating collar.The floating collar is discretized into a number of rigid sub-modules,the hydrodynamic loads acting on the floating collar are determined using the multi-rigid body hydrodynamic theory and the overall deformation of the structure is obtained using the curved beam element.The results show that:the vertical deformations of the floating collar at different positions are significantly different,the displacement amplitudes at the front and after points are larger than that in the middle,and this feature is more obvious with the increase of the wave frequency;the overall deformation of the floating collar decreases with the increase of diameter ratio and elastic modulus in the high-frequency range;the influence of draft on the vertical deformation amplitude of the floating collar is relatively small,and its main function is to intensify the oscillation phenomenon of the vertical deformation amplitude curve at the wave facing point in the high-frequency range;the influence of water depth on the vertical deformation of the floating collar varies at different positions and frequencies.