海洋平台抛锚方式模糊优化设计方法

海上钻井平台由于工作地点经常发生变化,工作环境条件随之改变,锚泊抛锚方式就要相应更改。本文针对深海半潜平台及其悬链线式系泊定位系统,运用平台与锚链耦合运动时域分析方法,对其水动力性能进行探索,并提出一种运用模糊算法计算平台抛锚方式优化设计方法,此方法可使钻井平台在风暴自存工况和钻井工作工况下更快更好地找到最佳抛锚方式。以一典型的半潜式钻井平台为例进行数值模拟,结果表明本文提出的方法是可行的,能够很方便地找到比较好的抛锚方式来满足相关要求。这种锚泊优化设计方法可为平台及其系泊系统设计提供参考。     

船舶管线隔振支座布局几何优化设计方法

海洋工程船舶管线隔振支座布局直接影响到管线整体的结构性能和经济性。在船舶管线隔振支座布局优化规范设计法的基础上,进一步提出了隔振支座布局几何优化设计模型与方法。该方法假定支座总数目,采用迭代优化算法求解,通过确定各支座的几何位置坐标实现布局优化。该迭代算法依据约束条件的满足情况及变步长的临界间距值来确定支座数量的减少与增加,最终得到较优的支座数目及间距。以应用于某舰艇的二维管道为例,用该方法对其隔振支座布局进行优化设计,并将不同目标函数下的优化结果同规范设计法所得结果进行了对比。比较结果表明,该模型与方法具有较好的可行性与稳定性。     

Sensitivity Analysis of Air Gap Motion with Respect to Wind Load and Mooring System for Semi-Submersible Platform Design

A design of semi-submersible platform is mainly based on the extreme response analysis due to the forces experienced by the components during lifetime. The external loads can induce the extreme air gap response and potential deck impact to the semi-submersible platform. It is important to predict air gap response of platforms accurately in order to check the strength of local structures which withstand the wave slamming due to negative air gap. The wind load cannot be simulated easily by model test in towing tank whereas it can be simulated accurately in wind tunnel test. Furthermore, full scale simulation of the mooring system in model test is still a tuff work especially the stiffness of the mooring system. Owing to the above mentioned problem, the model test results are not accurate enough for air gap evaluation. The aim of this paper is to present sensitivity analysis results of air gap motion with respect to the mooring system and wind load for the design of semi-submersible platform. Though the model test results are not suitable for the direct evaluation of air gap, they can be used as a good basis for tuning the radiation damping and viscous drag in numerical simulation. In the presented design example, a numerical model is tuned and validated by ANSYS AQWA based on the model test results with a simple 4 line symmetrical horizontal soft mooring system. According to the tuned numerical model, sensitivity analysis studies of air gap motion with respect to the mooring system and wind load are performed in time domain. Three mooring systems and five simulation cases about the presented platform are simulated based on the results of wind tunnel tests and sea-keeping tests. The sensitivity analysis results are valuable for the floating platform design.     

浮式生产储油船振动噪声混合数值预报

建立了可覆盖全频域的浮式生产储油船(FPSO,floating production storage and offloading)工作环境下振动噪声混合数值预报技术流程。将声学计算基本理论方法(有限元/边界元方法与统计能量法)应用于宽频带多噪声源的海洋工程船舶设计中,为设计能保证人员正常进行生产、生活噪声环境下的FPSO提供指导,满足国内船舶设计部门对该技术的迫切需要。文中采用声学边界元求解了FPSO上层建筑低中频域振动噪声,采用统计能量分析方法求解了高频域振动噪声,通过两种方法接力运用和不同模型间的顺利转换,实现了FPSO声学问题全频域分析。并讨论了各类方法的适用范围。     

深海无人遥控潜水器耐压电子舱结构设计与分析

研究深海无人遥控潜水器(ROV)耐压电子舱结构设计中涉及的力学分析技术。利用有限元数值分析方法校核耐压电子舱在深水条件下的强度、刚度与稳定性。根据深海耐压电子舱受力特点,优化其结构形式和尺寸,获得最优结构拓扑构型。对于耐压电子舱上下壳体接合面间接触问题,将非线性接触分析和简化分析法的计算结果进行比较。探讨加工误差与初始缺陷对耐压电子舱力学性能的影响。计算结果表明,耐压电子舱结构优选设计方案满足力学性能和重量要求,并且对加工误差与初始缺陷的影响不十分敏感。