中国南海深水环境FPSO波浪砰击荷载研究

Research on wave slamming load on FPSO in deep-water environment of the South China Sea

波浪砰击荷载是船体结构设计的关键要素之一,当前中国在FPSO结构设计方面仍需依赖国外规范,缺乏适用于中国南海深水环境条件的大型船体波浪砰击荷载设计依据。选取中国南海海域实测海洋环境参数,基于光滑粒子法建立了波浪-浮体全耦合数值分析模型,对不同波浪遭遇周期条件下FPSO受到的波浪砰击荷载进行研究,并将数值分析结果与常用规范计算结果进行对比。结果表明,同一波浪周期下,船体所受到的波浪砰击荷载最大值出现在水面线附近且位于船体中线,船体侧面与正面的波浪荷载峰值差别主要在水面线以上较高区域,水面线以上较低区域差值较小;不同规模波浪遭遇周期下,船体所受到的波浪砰击荷载变化规律基本一致,波浪砰击峰值荷载的增加幅度远比波高增加幅度要小。采用DNV和ABS规范计算的砰击荷载值约为本文模拟值的3倍,规范相关系数取值过于保守。因此,当以DNV规范作为设计标准时,中国南海深水环境中大型船体的波浪砰击荷载系数建议取值7~8;当采用ABS规范作为设计标准时,波高安全系数β建议取值0.6~0.7。研究结果可为南海深水环境FPSO波浪砰击荷载安全系数取值提供参考。

Wave slamming load is one of the key factors in hull structure design.At present,the structural design of FPSO in China still depends on foreign specifications,and there is no criterion for the design of wave slamming load on large hull suitable for the deep-water environment in the South China Sea.In this paper,the marine environmental parameters measured in the South China Sea are selected.Based on smoothed particle hydrodynamics method,a fully coupled wave-floating structure model is established,and the wave slamming loads on FPSO under different wave periods are studied.The numerical analysis results are compared with the results of common codes from the specifications.The results show that under the same wave period,the maximum wave slamming load on the hull appears near the water surface line and is in the center line of the hull.The difference of peak values of wave loads between the side and the front of the hull is mainly in the higher area above the water line,while the difference is small in the lower area above the water line.The behavior of wave slamming load on the hull is basically the same under different wave period.The increase of peak load of wave slamming is much smaller than that of wave height.The slamming load calculated by DNV and ABS specification is about 3 times of the simulation value in this work,and the correlation coefficient of specification is too conservative.According to DNV specification the wave slamming load coefficient of large hull in South China Sea is 7-8,and following the ABS specification the recommended value of wave height safety factorβis 0.6-0.7.The research results can provide a reference for the safety factor of wave slamming load on FPSO in deep-water environment of South China Sea.