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概念性地设计了一种新型半潜式海上风力机基础,确定了结构的型式和尺寸,对风浪联合作用下不同工况的风力机基础稳性进行了校核.考虑黏性阻尼和二阶波浪力的作用,计算分析了风力机基础的水动力系数、幅频运动以及动力响应特性.结果表明,经过改进的新型风力机基础具有良好的稳性和水动力性能,特别是在垂荡性能上有大幅的提升.波浪入射角度对垂荡的影响不大,但对其他自由度RAOs影响较大.垂荡、横摇和纵摇RAOs均存在一个主峰值和次峰值,但峰值周期均远离波能集中区.此外还发现,不同工况下风浪入射角对风机系统的动力响应和系泊力均有较大影响,相对于工作工况,极端工况下所受风荷载较小,但是系泊力更大. 相似文献
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在桁架式深吃水立柱式平台(Truss Spar)运输作业的浮卸过程中,半潜驳船不断压载下潜直到Truss Spar平台自浮后拖离驳船。针对浮卸作业的双浮体状态,提出Truss Spar平台在与半潜驳船发生接触情况下的载荷计算方案并进行结构应力水平评估。基于三维势流理论及SESAM软件,考虑平台及半潜驳船双浮体之间的水动力相互影响,首先对双浮体系统进行频域下求解,得到波浪诱导载荷;然后在时域下求解波浪中双浮体的运动方程及产生的接触力;最后将这两种载荷下的结构强度分析结果进行线性叠加,得到Truss Spar平台在波浪诱导载荷及接触力联合作用下结构应力水平。对比不同波浪方向及周期下的接触力结果,研究Spar平台结构整体应力水平及高应力区域位置特点,对总体强度水平进行评估。 相似文献
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针对深海半潜式平台及其系泊系统的水动力特性,运用时域耦合的分析方法,对一座水深为1 000 m的半潜式平台,及其悬链线式系泊系统的水动力性能进行探索,获得频域和时域响应结果。同时阐述了平台系泊系统的设计流程,并通过系泊系统参数的变化,研究其特性寻找影响系泊系统作用的一般规律,为平台及其系泊系统设计提供参考。 相似文献
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半潜式超大浮体连接器动力特性的一种时间序列分析方法 总被引:1,自引:2,他引:1
根据刚性模块弹性连接器 (RMFC)假设研究由 3个模块连接而成的半潜式超大浮体MobileOffshoreBase(MOB)的波浪载荷动力响应。模块和连接器动力响应根据时间序列法计算 ,这种方法包括海况模拟 ,波浪载荷计算和结构响应计算三个主要部分。通过对结构的适当简化 ,根据Airy波理论 ,Morrison公式以及流体中的结构运动方程、弹性连接器变形方程 ,计算求得MOB在不规则海况下的动力响应 ,并将其与相关文献中的结果进行比较 ,表明该方法有良好的精确性 相似文献
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深水半潜式钻井平台简化疲劳分析 总被引:1,自引:0,他引:1
研究适用于中国南海的深水半潜式钻井平台结构简化疲劳分析方法。依据中国南海环境条件,计算平台结构应力响应,得到平台结构应力范围长期Weibull分布形状参数。通过结构波浪应力的长期预报,计算得到平台寿命期一遇波浪载荷,依据寿命期一遇波浪载荷计算平台结构寿命期一遇最大热点应力范围。采用简化疲劳分析方法计算平台结构疲劳寿命,用谱疲劳分析方法验证简化疲劳分析结果的准确性,证实了简化疲劳分析方法相对保守,可应用于平台的设计。 相似文献
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《中国海洋大学学报(自然科学版)》2016,(12)
本文基于设计波法对某新型半潜式平台的整体强度进行了研究分析。不同于传统半潜式平台结构形式,该新型半潜式平台的浮筒一大一小,对应的两组立柱也是一大一小,因此结构关于中纵剖面是非对称的;此外该半潜式平台没有横撑结构。本文首先确定了作业吃水和自存吃水情况下新型半潜式平台四种典型危险工况对应的设计波参数,然后研究分析了不同危险工况下半潜式平台的整体强度,并对新型半潜式平台与传统半潜式平台在整体强度方面的差异进行了比较。研究结果表明,该新型平台的最大应力最易出现在大立柱内侧与甲板连接拐角区域,而传统有横撑半潜式平台的最大应力多发生在横撑与立柱连接区域。此外,浮筒与甲板之间的大倒角设计有助于提高新型半潜式平台的整体强度。 相似文献
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The Multiple Column Platform (MCP) semi-submersible is a newly proposed concept, which differs from the conventional semi-submersibles, featuring centre column and middle pontoon. It is paramount to ensure its structural reliability and safe operation at sea, and a rigorous investigation is conducted to examine the hydrodynamic and structural performance for the novel structure concept. In this paper, the numerical and experimental studies on the hydrodynamic performance of MCP are performed. Numerical simulations are conducted in both the frequency and time domains based on 3D potential theory. The numerical models are validated by experimental measurements obtained from extensive sets of model tests under both regular wave and irregular wave conditions. Moreover, a comparative study on MCP and two conventional semi-submersibles are carried out using numerical simulation. Specifically, the hydrodynamic characteristics, including hydrodynamic coefficients, natural periods and motion response amplitude operators (RAOs), mooring line tension are fully examined. The present study proves the feasibility of the novel MCP and demonstrates the potential possibility of optimization in the future study. 相似文献
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Since a self-elevating platform often works in water for a long time,the lattice leg is largely influenced by wave and current.The amplitude of leg joint stresses is a very important factor for the fatigue life of the platform.However,there are not many researches having been done on the mechanism and dynamic stress analysis of these leg joints.This paper focuses on the dynamic stress analysis and suppression methods of the leg joints of self-elevating platforms.Firstly,the dynamic stresses of the lattice leg joints are analyzed for a self-elevating platform by use of the 5th-order Stokes wave theory.Secondly,the axial and bending stresses are studied due to their large contributions to total stresses.And then,different joint types are considered and the leg-hull interface stiffness is analyzed for the improvement of the joint dynamic stress amplitude.Finally,some useful conclusions are drawn for the optimization design of the self-elevating platform. 相似文献
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In this paper Nondestructive Damage Detection (NDD) for offshore platforms is investigated under operational conditions. As is known, there is no easy way to measure ambient excitation, so damage detection methods based on ambient excitation have become very vital for the Structural Health Monitoring (SHM) of offshore platforms. The modal parameters (natural frequencies, damping ratios and mode shapes) are identified from structural response data with the Natural Excitation Technique (NExT) in conjunction with the Eigensystem Realization Algorithm (ERA) . A new method of damage detection is presented, which utilizes the invariance property of element modal strain energy. This method is to assign element modal strain energy to two parts, and defines two damage detection indicators. One is compression modal strain energy change ratio (CMSECR); the other is flexural modal strain energy change ratio (FMSECR). The present modal strain energy is obtained by incomplete modal shape and structural stiffness matr 相似文献
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随着海上风能的开发向深水发展,支撑风机的载体平台越来越受到关注。在经济性与安全性、稳定性的多重要求下,张力腿平台(TLP)在海洋风能资源的开发中体现出了重要地位。采用基于开源平台OpenFOAM开发的计算流体动力学(CFD)水动力学求解器naoe-FOAM-SJTU对一座处于中等水深下的风机基础水下TLP(STLP)的运动响应进行了数值模拟与研究。文中使用弹簧锚链模型模拟STLP的垂向系泊锁链系统,模拟该平台在不同波浪环境下的运动响应情况。首先将STLP单自由度自由衰减CFD模拟结果与已有全耦合时域分析结果进行对比,验证了naoe-FOAM-SJTU求解器及使用弹簧模型模拟STLP系泊系统的准确性与可靠性。随后在考虑非线性波浪载荷的情况下研究极端海况下与一般作业海况下STLP的运动响应情况,计算工况中的风机基础所受弯矩及锚链受力情况,并详细展示流场、速度场信息,分析高阶波浪成分、不同海况等条件对于STLP运动性能的影响。研究结果表明,TLP在中等水深中具有良好的运动性能,naoe-FOAM-SJTU求解器可以有效模拟水中生产平台在波浪环境下的水动力问题,并可以对整个流场进行可视化展示与分析。 相似文献
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The purpose of this paper is to validate a new method that can be used by offshore platform designers to estimate the added mass and hydrodynamic damping coefficients of potential Tension Leg Platform hull configurations. These coefficients are critical to the determination of the platform response particularly to high frequency motions in heave caused by sum-frequency wave forcing i.e. “springing”. Previous research has developed the means by which offshore platform designers can extrapolate anticipated full-scale hydrodynamic coefficients based on the response of individual model scale component shapes. The work presented here further evaluates the component scaling laws for a single vertical cylinder and quantifies the effects due to hydrodynamic interaction. Hydrodynamic interaction effects are established through a direct comparison between the superposition of individual hull component coefficients and those evaluated directly from complete hull configuration models. The basis of this comparison is established by the experimental evaluation of the hydrodynamic coefficients for individual hull components as well as partial and complete platform models. The results indicate that hydrodynamic interaction effects between components are small in heave, and validate component scaling and superposition as an effective means for added mass and damping coefficient estimation of prototype platforms. It is found that the dependency of damping ratio with KC for a TLP is almost identical to that of a single column, thus offering a scaling methodology for prototype damping ratio values. 相似文献
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研究了波致底切应力和二维辐射应力对悬沙的作用.首先对东山湾的水动力进行了数值模拟并与实测资料进行了对比检验,然后对东山湾悬浮泥沙进行了考虑波浪和不考虑波浪两种情况下的数值模拟并与实测资料进行了相关对比分析.在模式建立过程中,依据东山湾独特的窄口型半封闭河口海湾的特点,基于ECOMSED模式(2002)建立了东山湾三维水动力模型,并通过第三代海浪模式MASNUM加入了波浪对底切应力及辐射应力的影响,通过ECOMSED中的底边界层模型考虑了波浪增强底摩擦的作用,综合分析了东山湾的水动力及泥沙状况.结果表明在东山湾数值模拟中,该模式能较好地模拟这类海域的水动力及泥沙输运状况.在东山湾模拟计算中,潮流的作用强于波浪的作用,但考虑波浪因素后,泥沙模拟结果更好.在波浪的作用中,底切应力相比于二维辐射应力占有绝对的优势,两者相差2个量级以上,因此可以不考虑二维辐射应力的影响. 相似文献
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A Rapidly Deployable Stable Platform (RDSP) concept was investigated at Florida Atlantic University in response to military and civilian needs for ocean platforms with improved sea-keeping characteristics. The RDSP is designed to have enhanced sea-keeping abilities through the combination of a novel hull and thruster design coupled with active control. The RDSP is comprised of a catamaran that attaches via a hinge to a spar, enabling it to transit like a trimaran and then reconfigure so that the spar lifts the catamaran out of the water, creating a stable spar platform. The focus of this research is the mathematical modeling, simulation, and response characterization of the RDSP to provide a foundation for controller design, testing, and tuning. The mathematical model includes a detailed representation of residual drag, friction drag, added mass, hydrostatic and hydrodynamic pressure, and control actuator dynamics. Validation has been performed by comparing the simulation predicted motions of the RDSP operating in waves to the measured motions of the 1/10th scale prototype measured at sea. Resulting from this paper is an empirical assessment of the response characteristics of the RDSP that quantifies the performance under extreme conditions and provides a solid basis for controller development and testing. 相似文献