基于直接计算的半潜式平台结构总强度评估

Overall strength assessment of semi-submersible platform structures based on direct calculation

半潜式平台是船舶与海洋工程领域重要的浮式装置,采用直接计算法对某半潜式平台结构的总强度进行了评估.对半潜式平台结构进行有限元模型化,根据海况不同将静水、正常工作和风暴自存3种状态划分为48种计算工况,利用频域内的三维线性水动力理论和设计波法计算半潜式平台在各工况下的波浪载荷,同时考虑各工况下的莫里森力,风载荷,锚链预张力,吊车载荷、钻井载荷等载荷,进而计算平台在48种工况下的应力响应.根据ABS规范对平台结构总强度进行了校核,并对不满足许用应力标准的结构给出了相应的修改建议.结果表明,直接计算为平台结构强度评估提供了有效技术手段,评估结果可为半潜式平台的设计开发提供参考.

Semi-submersible platforms are important installations in naval architecture and ocean engineering. The overall strength assessment of a semi-submersible platform structure was carried out based on direct calculation. First, a finite element model of the semi-submersible platform was built, then the still water state, operating condition and survival condition were categorized into 48 load cases in term of different sea states, and the wave loads were computed using linear 3D hydrodynamics associated with the design wave approach. Morison force, wind load, mooring pre-tension, crane loads and drilling loads were also taken into account in each load. Then the stress responses of the semi-submersible platform structures under the 48 load cases were calculated. Finally ,the overall strength of the semi-submersible platform structure was assessed in accordance with the American Bureau of Shipping （ABS） rules and relevant suggestions were given for improving structural members where stresses exceeded the permissible stress criterion. This work showed that direct calculation is an effective technical means for strength assessment of semi-submersible platforms, and the assessment results can be a reference in the design and development of semi-submersible platforms.