冰区海上风电基础的抗冰性能分析

海上风电基础属于典型的柔性结构。由于冰与柔性抗冰结构相互作用的复杂性,长期以来尚未形成基于动冰力响应分析的结构设计。结构抗冰设计中大都是从极端荷载出发,只考虑最大静冰力或最大倾覆力矩。基于对渤海辽东湾柔性抗冰结构的多年监测,发现强烈的冰激振动引起柔性结构的风险性要远大于极端静冰荷载下结构的整体安全问题。为了明确冰区风电基础结构的抗冰性能及抗冰设计的合理性,文章结合基于多年现场冰与结构作用观测及冰荷载的研究成果,明确该类柔性结构与海冰作用形式及其动力特性;提出了柔性抗冰结构设计中应考虑的主要失效模式及评价方法。最后,以渤海某典型风电基础为例,对其抗冰性能进行评价。该文的研究可为寒区风电基础的抗冰设计及安全保障提供合理依据。     

冰激自升式钻井平台的动力响应分析

由于冰荷载研究的限制,冰区自升式钻井平台尚未形成基于动冰力响应分析的结构设计。为了合理地开展自升式平台结构的抗冰概念设计与安全评价研究,冰荷载下自升式钻井平台的动力响应分析是十分必要的。该文首先分析该类柔性结构在动冰荷载下的动力特性;其次,结合开展的自升式平台冰荷载模型实验研究,明确带齿条桩腿的自升式平台冰荷载作用形式;最后,对渤海某自升式钻井平台在典型冰况下进行冰振动力响应分析。文中的研究对冰区自升式钻井平台抗冰设计及冰振安全评估提供了合理的参考。     

渤海某新建升压站平台的抗冰性能分析

为了明确海上升压站平台设计中抗冰设计的合理性,以渤海某新建升压站平台为例,采用有限元数值模拟方法分析典型冰况下升压站平台的抗冰性能,与渤海典型的油气平台对比表明,动冰力下,结构的振动不明显,在极值静冰下结构具有很大的静力安全储备;新设计的升压站平台具有较好的抗冰性能。     

半潜式海洋平台抗冰性能分析

全球范围内,北极海底油气资源十分丰富。随着钻探技术的进步,加上易开采油气资源变少,北极地区的油气开采已经是势在必行。半潜式海洋平台拥有较强的抵抗极端环境的能力,在冰区不同的冰况下亦可操作。由于冰与不同结构物作用的复杂性,长期以来尚未形成关于半潜式海洋平台在海冰作用下的设计准则。本文通过对典型半潜式平台与海冰相互作用机理与冰载荷模型分析,提出了该类结构在海冰作用下的主要失效模式及评价方法。最后,以我国首座北极海域传统半潜式钻井平台为例,对其抗冰性能进行了评价,明确了半潜式平台在抗冰设计及安全保障中需要考虑的关键失效模式。     

自升式平台的结构强度分析

自升式钻井平台是指具有活动桩腿,并可将平台主体上升到海面以上一定高度进行作业的平台,它在海洋石油开发中被广泛采用.本文采用Zenscad海工结构分析软件,对一个典型的自升式钻井平台进行了结构静力分析,并分别针对预压载工况、正常作业工况以及极端工况,对平台主体和桩腿的强度进行了校核.荷载主要是考虑了结构自重、功能荷载以及环境荷载.有限元建模主要采用了梁单元和板壳单元,其中梁单元用于模拟桩腿、强横梁、底肋板、纵桁、舱壁垂直和水平扶强材等强力构件,板壳单元用于模拟主甲板、底板、船体外围板以及舱壁板等结构.基于上述分析,结果给出了构件的应力水平、最大节点位移以及桩基支反力.本文对自升式平台的结构设计和在位分析具有一定的参考价值.     

冰区海洋平台结构整体抗力及极值响应的概率统计特性

冰荷载是冰区海洋平台设计的控制荷载,极值冰力直接危害着平台结构整体的安全。文章以渤海辽东湾导管架海洋平台为例,考虑了海洋平台结构抗冰设计的各种不确定性;基于Pushover方法,得到了海洋平台结构的简化力学模型,分析了极值冰荷载下海洋平台结构整体抗力以及极值响应;并且采用K-S检验法,对结构整体抗力及极值冰力响应的概率统计特性进行了分析。结果表明,简化的海洋平台分析模型合理,并且结构抗力参数服从正态分布;而极值冰力下,结构顶点最大位移服从对数正态分布。以上结论可为研究冰区海洋平台整体安全可靠性分析提供参考。     

渤海单立柱桶型基础平台冰振分析

桶形基础平台是一种新型的海洋结构,由于目前对该结构的研究集中在桶基失效及承载力方面,其抗冰振性能还很模糊。文章基于对渤海单立柱式桶基平台的多年现场监测,发现其冰振加速度响应显著,明显高于导管架平台结构。利用谱分析方法对一实际桶基平台进行了冰振疲劳寿命分析,计算结果表明,关键点疲劳寿命符合规范要求。最后,提出此类结构冰振抑制策略,为其结构抗冰设计提供依据。     

负压桶型风电基础的抗冰性能

针对负压桶型风电基础的抗冰性能还不明确等问题,以渤海某桶型风电基础为例,采用ANSYS数值模拟的方法,分析该类风电基础在典型冰况下的抗冰效果。结果表明,负压桶型风电基础在极值静冰力及动冰力的作用下均具有良好的抗冰性能。     

我国海上导管架平台抗冰锥体的设计实践

冰激振动是渤海重冰区导管架平台的主要危害.渤海重冰区导管架平台在腿柱上安装了抗冰锥体,基本解决了平台冰激振动问题.主要阐述了抗冰锥体的基本抗冰原理和设计方法,分析了渤海典型导管架平台抗冰锥体的设计实践,对渤海重冰区导管架平台和抗冰锥体的设计提出了建议.     

锥体海洋平台结构冰荷载的离散单元分析

在冰区油气开发中,锥体结构可以有效降低冰力,避免强烈的冰激振动,是目前渤海油气平台的主要结构形式。为研究海冰与锥体结构的相互作用过程,文章建立了适用于模拟海冰破碎特性的离散单元模型。该模型将海冰离散为若干个具有粘接-破碎功能的颗粒单元,并通过海冰弯曲试验确定了单元间的粘接强度;然后对海冰与锥体结构的作用过程进行了数值计算,获得了相应的动冰荷载及冰振响应;在此基础上讨论了不同锥角影响下冰荷载及结构振动响应的变化规律。结果表明,水平方向冰荷载及结构冰振响应随锥角的增加明显增加,而竖直方向冰荷载则显著降低。该离散单元模型还可进一步应用于不同类型抗冰结构的冰荷载分析,有助于解决冰区结构物的抗冰结构设计和冰致疲劳分析。     

Research on short-term dynamic ice cases for dynamic analysis of ice-resistant jacket platform in the Bohai Gulf

Jacket platforms in the Bohai Gulf are often victims of random ice-induced vibrations. Their design originally did not account for dynamic ice loading on the jacket structures and significant ice-induced vibrations have been observed during winters. So it is urgent to find out as to how to consider the dynamic ice loading in the design stage of an ice-resistant jacket platform in the Bohai Gulf. In this paper, based on the state-of-art developments of dynamic ice load and ice–structure interaction, the authors proposed two different approaches to determine the short-term dynamic ice cases for dynamic analysis of ice-resistant jacket platform in the Bohai Gulf, named as the failure probability-based approach and the expected loss-based approach. Considering the variation of the ice environments and the variability of ice-resistant structure's properties, the random ice spectrum and the pseudo-excitation method (PEM) are employed to improve the efficiency of the procedure. Through finite element method (FEM) modeling of the real ice-resistant jacket platforms in the Bohai Gulf, such as MSW, MUQ and NW, the characteristics of the two proposed approaches have been investigated and compared. This paper provides an open and universal framework to assist designers and owners for determining the short-term dynamic ice cases in the Bohai Gulf, in which more information can be considered in the procedure to update and modify the results if available.     

抗冰海洋平台的全寿命优化设计I-理论与模型

文章基于投资—效益准则,建立了抗冰平台全寿命总费用最小的优化设计模型;考虑了多种类型的性能要求(结构、设备、人员),并建立了相关判据;提出了包括结构的初始费用、维修费用和期望损失费用的冰区海洋平台全寿命总费用评估模型;提出了平台结构主要功能的确定及描述方法、相应的功能失效损失值估计模型。     

海上自升式平台动力分析方法研究(英文)

A jack-up platform,with its particular structure,showed obvious dynamic characteristics under complex environmental loads in extreme conditions.In this paper,taking a simplified 3-D finite element dynamic model in extreme storm conditions as research object,a transient dynamic analysis method was proposed,which was under both regular and irregular wave loads.The steps of dynamic analysis under extreme conditions were illustrated with an applied case,and the dynamic amplification factor(DAF) was calculated for each response parameter of base shear,overturning moment and hull sway.Finally,the structural response results of dynamic and static were compared and analyzed.The results indicated that the static strength analysis of the Jack-up Platforms was not enough under the dynamic loads including wave and current,further dynamic response analysis considering both computational efficiency and accuracy was necessary.     

浮式抗冰平台设计理念及水动力特性研究

钻探极地地区近海石油和天然气资源对移动式离岸钻井平台的水动力性能、抗冰性能和作业性能有着极大的要求。本文主要介绍了浮式抗冰平台的设计方案,并结合当今最新一款半潜式抗冰平台的设计理念,分别从频域和时域分析的角度与传统的半潜式平台作对比,分析得出其具有优越的水动力性能,垂荡、横摇、纵摇运动响应都优于传统的半潜平台,为下一步抗冰性能分析及其关键技术的研究做基础,同时也给半潜式平台带来新的设计理念,为浮式抗冰平台的设计建造提供合理思路。     

Estimation of fatigue damage and extreme response for a jack-up platform

Results from four different methods for stochastic dynamic response analysis of a proposed jack-up platform are compared. This structure exhibits both significant dynamic amplification and non-linear transfer of sea elevation into load effects. Both estimation of extreme response and fatigue damage are considered. The most complex procedure based on time-domain simulation and step-by-step integration is employed as a benchmark for assessment of three simplified methods. The simplifications consist of various types of linearization in conjunction with transfer function approximations. Applicability of the methods to structures with increasingly non-linear behaviour and dynamic amplification is briefly discussed.     

波斯湾中受随机波作用的某新建离岸导管架平台时域动力分析研究（英文）

API RP2 A WSD is a design code in practice for design of jacket platforms in the Persian Gulf but is based on the Gulf of Mexico environmental condition. So for the sake of using this code for the Persian Gulf, it is better to perform a calibration based on this specific region. Analysis and design of jacket platforms based on API code are performed in a static manner and dynamic analysis is not recommended for such structures. Regarding the fact that the real behavior of the offshore jacket platforms is a dynamic behavior, so in this research, dynamic analysis for an offshore jacket platform in the Persian Gulf under extreme environmental condition is performed using random time domain method. Therefore, a new constructed offshore jacket platform in the Persian Gulf is selected and analyzed. Fifteen, 1-h storm, simulations for the water surface elevation is produced to capture the statistical properties of extreme sea condition. Time series of base shear and overturning moment are derived from both dynamic and static responses. By calculating the maximum dynamic amplification factor(DAF) from each simulation and fitting the collected data to Weibull distribution, the most probable maximum extreme(MPME) value for the DAF is achieved. Results show that a realistic value for DAF for this specific platform is 1.06, which is a notable value and is recommended to take into practice in design of fixed jacket platform in the Persian Gulf.     

自升式平台风载荷的空气动力学干扰研究

风载荷是白升式平台的主要控制载荷,现行规范在计算风载荷时主要采用面积投影法,不考虑空气动力学干扰的影响,结果偏于保守。以自主研发的122m（400ft）自升式平台为例,通过风洞实验得到其各风向角下的干扰因子伊。在此基础上,采用求解RANS方程的方法,结合k—ε湍流模型对风载荷的空气动力学干扰现象进行数值模拟,所得伊值与实验结果吻合良好,揭示了这种干扰现象对自升式平台风载荷的影响。