Marine Structures最新文献

Upper bound solution of the vertical bearing capacity of the pile-bucket composite foundation of offshore wind turbines 海上风力涡轮机桩桶复合地基垂直承载力的上限值解法

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-26 DOI: 10.1016/j.marstruc.2024.103728

Guangsi Chen, Hao Gu, Run Liu, Tianliang Li, Chao Liang

Pile-bucket composite foundations are regarded as a promising solution for offshore wind power infrastructure. However, accurately assessing their vertical ultimate bearing capacity remains a technical challenge. Therefore, establishing an upper bound solution of the ultimate bearing capacity of the composite foundations is of significant importance for their promotion and application. This study begins with small-scale model tests, using Abaqus for modeling based on the relevant test conditions. Next, following model validation, the vertical bearing capacity of the composite foundations under different H/D ratios and the corresponding soil failure modes are investigated. According to the upper limit method and the ultimate equilibrium theory, the kinematic velocity field is subsequently constructed to derive the upper bound solution of the vertical bearing capacity. Finally, the effectiveness and accuracy of the proposed theoretical upper bound solution are verified against the results of model tests, and this study hopes to provide a reference for the future design of vertical bearing capacity of pile-bucket composite foundations.

桩桶复合地基被认为是海上风电基础设施的一种有前途的解决方案。然而，准确评估其垂直极限承载力仍是一项技术挑战。因此，建立复合地基极限承载力的上限解决方案对其推广和应用具有重要意义。本研究首先进行小规模模型试验，根据相关试验条件使用 Abaqus 进行建模。接着，在模型验证后，研究了不同高径比下复合地基的竖向承载力以及相应的土体破坏模式。随后，根据上限法和极限平衡理论，构建运动速度场，得出竖向承载力的上限解。最后，根据模型试验结果验证了所提出的理论上限解的有效性和准确性，本研究希望能为今后桩桶复合地基的竖向承载力设计提供参考。

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引用次数: 0

Impact of hull flexibility on the global performance of a 15 MW concrete-spar floating offshore wind turbine 船体灵活性对 15 兆瓦混凝土支柱浮式海上风力涡轮机总体性能的影响

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-25 DOI: 10.1016/j.marstruc.2024.103724

Ikjae Lee , Moohyun Kim , Chungkuk Jin

In this study, we investigated the impact of the hull flexibility of 15MW spar-type FOWT (floating offshore wind turbine) on the global dynamics/performance analysis. Until recently, the rigid hull (floating foundation) model with flexible tower and RNA (rotor-nacelle assembly) has been used as industry standard procedure in the global performance analysis of FOWTs. Since the FOWT size continues to increase beyond 20MW, there has been increasing concern of the effect of hull flexibility on its global performance. The present study is intended to provide representative insights on this subject. Global performance analysis of the 15MW WindCrete spar is examined based on the conventional hull-rigid and the DMB (discrete-module-beam) models including hull flexibility. Coupled aero-hydro-servo-elastic-mooring dynamic simulations were carried out with the rigid-hull and DMB (discrete-module-beam) models under various combinations of irregular waves, sheared currents, and full-field turbulent winds. The lowest fore-aft bending-mode natural frequency is shifted toward lower frequency from 0.52 to 0.41 Hz after including hull flexibility. Platform rigid 6-DOF (degree-of-freedom) motions and mooring tensions by the DMB model are little changed but nacelle horizontal accelerations and tower-base bending moments may be appreciably increased compared to the rigid-hull model.

在本研究中，我们探讨了 15MW spar 型 FOWT（浮式海上风力涡轮机）船体柔性对全局动态/性能分析的影响。直到最近，带有柔性塔架和 RNA（转子-机舱组件）的刚性船体（浮动基础）模型一直被用作 FOWT 全局性能分析的行业标准程序。随着 FOWT 规模不断扩大，超过 20MW，人们越来越关注船体柔性对其总体性能的影响。本研究旨在就此问题提供有代表性的见解。根据传统的船体刚性模型和包括船体柔性在内的 DMB（离散模块梁）模型，对 15MW WindCrete spar 进行了全局性能分析。在不规则波浪、剪切流和全场湍流风的不同组合下，使用刚性船体和 DMB（离散模块梁）模型进行了航空-水力-伺服-弹性-锚泊耦合动态模拟。将船体柔性考虑在内后，最低的前后弯曲模式固有频率从 0.52 Hz 降至 0.41 Hz。与刚性船体模型相比，DMB 模型的平台刚性 6-DOF（自由度）运动和系泊张力变化不大，但机舱水平加速度和塔基弯矩可能会明显增加。

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引用次数: 0

Non-linear dynamic behavior of T0 and T90 mesopelagic trawls based on the Hilbert–Huang transform 基于希尔伯特-黄变换的 T0 和 T90 中上层拖网的非线性动态行为

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-23 DOI: 10.1016/j.marstruc.2024.103727

Bruno Thierry Nyatchouba Nsangue , Hao Tang , Ruben Mouangue , Wei Liu , Achille Njomoue Pandong , Liuxiong Xu , Fuxiang Hu , Leopold Tcham

Although adopting the T90 mesh orientation on the trawl net can improve the selectivity of the trawl codend, it is unknown whether the T90 mesh orientation influences the dynamic behavior of the trawl system. Therefore, this study uses non-linear dynamic analysis to examine the effect of mesh orientations, mesh size, and twine diameter on the mesopelagic trawls' fluttering motions and hydrodynamic force responses. Three trawls are designed with different mesh orientations (T0 and T90), mesh sizes (40 mm and 60 mm), and twine diameters (0.96 mm and 1.11 mm) on the codend and codend extension sections of the trawl model based on Tauti's law. These trawls are tested in a flume tank under various flow velocities and catch sizes. A time-frequency analysis method based on the Hilbert–Huang transform is utilized to analyze each trawl's dynamic responses, including motions and drag force responses. The results are compared with those obtained through Fourier analysis using power spectral density. The results highlight that the oscillation amplitude of the surge motion of the T90 trawl is higher than that of the T0 trawl. In contrast, the T90 trawl's heave motion oscillation amplitude is smaller. The dominant frequency of the periodic high-energy coherent structures of the surge and heave motions are detected at a low frequency. The surge and heave motions of the T0 trawl have a greater response to the current components with lower frequencies than that of the T90 trawl. An increase in mesh size, a decrease in twine diameter, and a change in mesh orientation decrease the drag force. The inherent characteristic oscillations of the drag force response for the three trawl models are synchronized with the low-frequency characteristic of surge and heave motions. The gravity periods of the low-frequency mode components of drag force, surge motion, and heave motion for the T90 trawl are higher than those for the T0 trawls. In other words, the T90 trawl is more stable and selective than the T0 trawl. The findings of this study offer important information for comprehending and enhancing the selectivity of trawls in marine mesopelagic fisheries, particularly for exposing the effects of mesh orientation and design parameters on trawl performances.

虽然在拖网上采用 T90 网目方向可以提高拖网鳕鱼的选择性，但 T90 网目方向是否会影响拖网系统的动态行为尚不清楚。因此，本研究采用非线性动力学分析方法，研究网目方向、网目尺寸和麻绳直径对中上层拖网的飘动运动和水动力响应的影响。根据陶氏定律，在拖网模型的鳕尾和鳕尾延伸部分设计了三种不同网目方向（T0 和 T90）、网目尺寸（40 毫米和 60 毫米）和麻绳直径（0.96 毫米和 1.11 毫米）的拖网。这些拖网在不同流速和渔获量的水槽中进行了测试。利用基于希尔伯特-黄变换的时频分析方法分析了每种拖网的动态响应，包括运动和阻力响应。分析结果与使用功率谱密度进行傅立叶分析得出的结果进行了比较。结果表明，T90 拖网的浪涌运动振幅高于 T0 拖网。相比之下，T90 拖网的起伏运动振幅较小。探测到的浪涌和翻腾运动的周期性高能相干结构的主频较低。与 T90 拖网相比，T0 拖网的涌浪和翻浪运动对频率较低的电流成分的响应更大。网目尺寸的增加、麻线直径的减小以及网目方向的改变都会降低阻力。三种拖网模型拖力响应的固有特征振荡与涌浪和波浪运动的低频特征同步。T90 拖网的阻力、涌浪运动和波浪运动的低频模式分量的重力周期高于 T0 拖网。换句话说，T90 拖网比 T0 拖网更稳定，选择性更强。这项研究结果为理解和提高拖网在海洋中上层渔业中的选择性提供了重要信息，特别是揭示了网目方向和设计参数对拖网性能的影响。

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引用次数: 0

Further development of offshore floating solar and its design requirements 海上浮动太阳能的进一步发展及其设计要求

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-23 DOI: 10.1016/j.marstruc.2024.103730

Arefeh Emami , Madjid Karimirad

Floating solar platform (FSP) installations in coastal waters provide a significant energy source for reaching the goal of global net-zero emissions by 2050. These alternative and beautiful green energy installations offer substantial renewable energy generation potential. However, developing robust design solutions is crucial for fully exploiting such potential in offshore environments. This review explores the fundamental requirements for designing FSPs in offshore settings from an engineering perspective. A primary focus is on the hydrodynamic and aerodynamic characteristics, stochastic behaviours, and nonlinear phenomena associated with these structures. Key design parameters such as geometry, modularity, connectivity, and mooring systems are subjected to comprehensive analysis. The interaction between wind, waves, and FSP dynamics is examined, with particular attention to wind-wave coupling. Additionally, complex nonlinear wave phenomena, such as slamming, overtopping, green water, sloshing, ringing, and springing, are thoroughly discussed. The review also highlights the application of previous fluid-structure interaction research in FSP design and development, addressing challenges and variations encountered in this field. Furthermore, the role of data-driven approaches, particularly machine learning, in enhancing the design and development of FSPs is illustrated. This comprehensive examination provides a more delicate understanding of the design challenges and requirements inherent in this rapidly evolving technological field.

沿海水域的浮动太阳能平台（FSP）装置为实现到 2050 年全球净零排放的目标提供了重要的能源来源。这些美观的替代性绿色能源装置具有巨大的可再生能源发电潜力。然而，要想在近海环境中充分挖掘这些潜力，开发稳健的设计方案至关重要。本综述从工程学角度探讨了在近海环境中设计可再生能源发电站的基本要求。主要重点是与这些结构相关的流体动力和空气动力特性、随机行为和非线性现象。对几何形状、模块化、连接性和系泊系统等关键设计参数进行了全面分析。研究了风、波浪和 FSP 动力学之间的相互作用，尤其关注风-波耦合。此外，还深入讨论了复杂的非线性波浪现象，如撞击、倾覆、绿水、荡漾、振铃和弹跳。该综述还重点介绍了以往流固耦合研究在 FSP 设计和开发中的应用，探讨了该领域遇到的挑战和变化。此外，还说明了数据驱动方法，特别是机器学习，在加强 FSP 设计和开发中的作用。这项全面的研究使人们对这一快速发展的技术领域所固有的设计挑战和要求有了更细致的了解。

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引用次数: 0

Dynamic analysis in polar exploration: Fluid-structure interaction modeling of projectile colliding with floating ice during water entry 极地探索中的动态分析：射弹入水时与浮冰碰撞的流体-结构相互作用建模

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-21 DOI: 10.1016/j.marstruc.2024.103729

Xinyu Hu, Yingjie Wei, Cong Wang

In polar resource exploration, the interaction between polar detectors and floating ice, as well as their water entry mechanisms, are crucial for ensuring effective detector operation and data collection. This study developed a fluid-structure interaction (FSI) model to simulate the water entry of the projectile in a multidegree motion state upon collision with the floating ice, and the numerical method was validated through experiments. This study analyzes the mechanisms of cavity evolution and the laws of cavity pinch-off. This analysis further explores the motion states and dynamic characteristics under the interaction between the projectile and the floating ice. Additionally, this study also considers the influence of structural parameters of the floating ice, including thickness (L_t), width (L_w), and collision position (S_d), on the water entry process. The study reveals that increasing the submergence depth of the floating ice enhances the stability between the floating ice and water, and can mitigate flow separation phenomena generated by passive motion under inertial effects. Variations in the floating ice thickness significantly affect the cavity evolution and the projectile's underwater motion state. Conversely, variations in the floating ice width notably affect the liquid level disturbances, the development of splash crowns, and the evolution of passive water entry cavities. In specific multidegree motion states, various collision positions do not alter the evolution form of water entry cavities, yet the variation in collision positions notably affects floating ice displacement. As the collision position shifts from the center to the side edge of the floating ice, both the hydrodynamic forces on the projectile and the stress on the floating ice gradually decrease, with the decrease in hydrodynamic forces being the most significant, reaching up to 58%. This study is important for enhancing multi-body fluid-structure interaction algorithms and advancing polar exploration engineering development.

在极地资源勘探中，极地探测器与浮冰之间的相互作用及其入水机制对于确保探测器的有效运行和数据采集至关重要。本研究建立了流固耦合（FSI）模型，模拟射弹与浮冰碰撞后的多度运动状态下的入水过程，并通过实验对数值方法进行了验证。本研究分析了空腔演化机理和空腔挤压规律。该分析进一步探讨了弹丸与浮冰相互作用下的运动状态和动态特性。此外，本研究还考虑了浮冰的结构参数，包括厚度（Lt）、宽度（Lw）和碰撞位置（Sd）对入水过程的影响。研究表明，增加浮冰的浸没深度可增强浮冰与水之间的稳定性，并可减轻惯性作用下被动运动产生的水流分离现象。浮冰厚度的变化会显著影响空腔的演变和弹丸的水下运动状态。相反，浮冰宽度的变化会明显影响液面扰动、飞溅冠的形成以及被动进水空腔的演变。在特定的多度运动状态下，不同的碰撞位置不会改变进水腔的演变形式，但碰撞位置的变化会显著影响浮冰的位移。当碰撞位置从浮冰中心向侧边移动时，弹丸所受的流体动力和浮冰所受的应力都逐渐减小，其中流体动力的减小最为显著，最大可达 58%。这项研究对于改进多体流固耦合算法、推动极地探测工程发展具有重要意义。

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引用次数: 0

Dynamic analysis of breaking wave impact on a floating offshore wind turbine via smoothed particle hydrodynamics 通过平滑粒子流体力学分析破浪对漂浮式海上风力涡轮机的动态影响

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-21 DOI: 10.1016/j.marstruc.2024.103731

Shengzhe Wang , Wei-Liang Chuang

This work leverages Lagrangian smoothed particle hydrodynamics (SPH) to explore the structural and hydrodynamic response of floating offshore wind turbines (FOWT) subject to impulsive breaking waves. The SPH formulation was first validated against breaking wave impact on a model tension leg platform (TLP) which demonstrated good consistency with experimental results. Following validation, wave focusing was utilized to generate both breaking and nonbreaking extreme waves impacting a moored semi-submersible FOWT at full scale. Impulsive forces and accelerations resulting from the plunging breaker were observed to exceed that of nonbreaking waves by up to 70 % and 230 %, respectively, and were highly sensitive to the wave impingement location relative to the FOWT. However, wave breaking did not appear to significantly influence rigid body motions and yielded lower mooring tensions than its nonbreaking counterpart due to the short duration of impact. This work ultimately demonstrates the applicability of SPH for the simulation of breaking wave interactions with floating bodies and provides further impetus towards the study of FOWTs under such conditions.

这项研究利用拉格朗日平滑粒子流体力学（SPH）来探索浮式海上风力涡轮机（FOWT）在冲击破浪作用下的结构和流体力学响应。首先根据破浪对模型张力腿平台（TLP）的影响对 SPH 公式进行了验证，结果表明与实验结果十分吻合。验证结束后，利用波聚焦生成了冲击全尺度系泊半潜式 FOWT 的破浪和非破浪极端波浪。据观察，由猛烈破浪产生的冲击力和加速度分别超过非破浪的 70% 和 230%，并且对相对于 FOWT 的波浪冲击位置高度敏感。不过，由于冲击持续时间较短，破浪似乎不会对刚体运动产生重大影响，而且与非破浪相比，破浪产生的系泊张力较低。这项工作最终证明了 SPH 在模拟破浪与浮体相互作用方面的适用性，并进一步推动了在这种条件下对 FOWT 的研究。

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引用次数: 0

Experimental and numerical investigation on the influence of bilge keel shape on roll damping 舭龙骨形状对滚动阻尼影响的实验和数值研究

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-20 DOI: 10.1016/j.marstruc.2024.103725

Hasan Islam Copuroglu , Emre Pesman , Toru Katayama

Excessive roll amplitudes due to roll motion are undesirable in marine ships. Consequently, it is imperative to conduct a detailed analysis of roll motion and the associated roll damping characteristics. This study experimentally and numerically investigates the roll damping characteristics of bilge keels with various geometric shapes on a ship model under different roll amplitudes. By comparing the non-dimensional roll damping coefficients obtained from experiments and numerical analyses, it is observed that bilge keels with geometries differing from the conventional plate shape exhibit distinct roll damping coefficients. Specifically, bilge keels with sharper tip ends demonstrate higher roll damping coefficients. Based on these findings, it is recommended that the corners and tip end of bilge keels be sharpened to enhance the roll damping coefficient.

滚动运动造成的过大滚动幅度在船舶中是不可取的。因此，必须对滚动运动和相关的滚动阻尼特性进行详细分析。本研究通过实验和数值方法研究了不同滚动振幅下具有不同几何形状的船底龙骨在船舶模型上的滚动阻尼特性。通过比较实验和数值分析获得的非尺寸滚动阻尼系数，可以观察到不同于传统板状几何形状的舱底龙骨表现出不同的滚动阻尼系数。具体来说，龙骨顶端更尖锐的龙骨表现出更高的滚动阻尼系数。基于这些发现，建议对船底龙骨的边角和顶端进行锐化处理，以提高滚动阻尼系数。

引用次数: 0

Design of a quick-connection device for installing pre-assembled offshore wind turbines 设计用于安装预组装海上风力涡轮机的快速连接装置

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-16 DOI: 10.1016/j.marstruc.2024.103720

Behfar Ataei , Zhengru Ren , Karl Henning Halse

Higher wind velocities and lower wind shear are two motivations driving the development of floating offshore wind turbines (OWTs). However, such designs suffer from high expenses and complicated installation scenarios. Installation of offshore wind turbines is challenging due to the unpredictable nature of the environment and the technical complexities, especially at offshore sites. Mating of OWT on top of the pre-installed substructure is one of the critical stages of the installation operation. Grouted, welded, and bolted connections are utilized conventionally, but all have shortcomings. Welded and grouted connections suffer from fatigue forces, while a bolted connection requires minimal installation tolerances and sensitivity to impact forces. The design of a quick connection device (QCD) is expected to reduce the installation time, expand the operational weather window, and overcome the limitations of the earlier connection devices.

The QCD described here comprises conic cross-sections, circular plates, and stiffeners connected to the floating substructure and OWT. This research uses a global model to estimate the relative velocities and displacements between the OWT and spar buoy. Furthermore, a local finite element model is developed to assess the influence of the impact forces and the design of the connection device. Implementing the hydrostatic stiffness of the floating spar within the impact simulations improved the simulation fidelity and reduced the impact damage. Different impact scenarios are performed, and the sensitivity of impact damage concerning the distribution of impact initiation points is assessed. Furthermore, an active control mechanism is used to reduce the relative motions between the installation vessel and the floating substructure. It is concluded that utilizing the anti-swing active control system minimizes the impact velocity and impact damage. This research can be extended by optimizing the design of the quick connection device.

更高的风速和更低的风切变是推动漂浮式海上风力涡轮机（OWTs）发展的两大动力。然而，这种设计存在成本高、安装复杂的问题。由于环境的不可预测性和技术的复杂性，海上风力涡轮机的安装具有挑战性，尤其是在近海地点。将海上风力涡轮机安装到预安装的下部结构顶部是安装操作的关键阶段之一。传统的连接方式有灌浆连接、焊接连接和螺栓连接，但所有连接方式都存在缺陷。焊接和灌浆连接会受到疲劳力的影响，而螺栓连接则要求最小的安装公差和对冲击力的敏感性。快速连接装置（QCD）的设计有望缩短安装时间，扩大作业气象窗口，并克服早期连接装置的局限性。此处描述的快速连接装置由圆锥截面、圆板和与浮式下部结构和 OWT 连接的加强筋组成。本研究使用全局模型来估算 OWT 和 spar 浮标之间的相对速度和位移。此外，还开发了一个局部有限元模型，以评估冲击力和连接装置设计的影响。在撞击模拟中采用浮标的静水刚度提高了模拟的逼真度并减少了撞击破坏。对不同的撞击情景进行了模拟，并评估了撞击破坏对撞击起始点分布的敏感性。此外，还采用了一种主动控制机制来减少安装船和浮动下部结构之间的相对运动。结论是，利用防摆动主动控制系统可将撞击速度和撞击损害降至最低。这项研究可通过优化快速连接装置的设计加以扩展。

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引用次数: 0

An ULS reliability-based design method for mooring lines using an efficient full long-term approach 基于 ULS 可靠性的系泊缆线设计方法，采用高效的全长期方法

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-14 DOI: 10.1016/j.marstruc.2024.103718

Marina Leivas Simão , Luis Volnei Sudati Sagrilo , Paulo Maurício Videiro , Mauro Costa de Oliveira

In the long-term scenario, the environmental actions to which floating offshore structures are subjected to, such as waves, wind and current, are non-stationary stochastic processes. However, this long-term behavior is usually modeled as a series of short-term stationary conditions. In a full long-term analysis approach, an estimate of the N-year response can be obtained through a multi-dimensional integration over expected short-term environmental conditions. An innovative and more efficient long-term integration approach based on the Importance Sampling Monte Carlo Simulation (ISMCS) method is presented, where the uniform distribution over an environmental contour is used as the sampling function. In parallel, a multi-dimensional joint environmental model that statistically describes all relevant environmental parameters is employed, contemplating linear and directional variables, and thoroughly accounting for the occurrences of wind waves and swell. The methodology is applied to two FPSOs systems installed in Brazilian ultradeep waters. Ultimately, a design-oriented procedure based on the developed methodologies is provided, using an Ultimate Limit State (ULS) reliability-based design with calibrated safety factors in an LRFD (Load and Resistance Factors Design) format. It is shown that the developed procedures can be powerful tools to account for the simultaneous occurrence of wind sea and swell waves in offshore system response evaluations required in the design and life extension analyses.

在长期情况下，海上浮动结构所受到的环境影响，如海浪、风和水流，都是非静态的随机过程。然而，这种长期行为通常被模拟为一系列短期静态条件。在完整的长期分析方法中，可以通过对预期的短期环境条件进行多维整合来获得 N 年响应的估计值。本文提出了一种基于重要度抽样蒙特卡洛模拟（ISMCS）方法的创新型、更高效的长期积分方法，即使用环境等值线上的均匀分布作为抽样函数。同时，还采用了一个多维联合环境模型，该模型可统计描述所有相关环境参数，考虑线性和方向变量，并全面考虑风浪和涌浪的发生。该方法适用于安装在巴西超深水域的两个 FPSO 系统。最后，在所开发方法的基础上提供了一个以设计为导向的程序，该程序采用基于极限状态（ULS）的可靠性设计，并以 LRFD（载荷和阻力系数设计）格式校准了安全系数。结果表明，所开发的程序是一种强大的工具，可以在设计和延寿分析所需的近海系统响应评估中考虑到同时出现的风浪和涌浪。

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引用次数: 0

A probability-based study on failure mechanism and quantitative risk analysis for buried offshore pipelines subjected to third-party impact loads, exploring the effects of spatial variability of soil strength 基于概率的研究，探讨土壤强度空间变化的影响，研究承受第三方冲击荷载的埋地海上管道的失效机理和定量风险分析

IF 4 2区工程技术 Q1 ENGINEERING, CIVIL

Marine Structures

Pub Date : 2024-11-14 DOI: 10.1016/j.marstruc.2024.103719

Fengyuan Jiang , Sheng Dong , Carlos Guedes Soares

Burial is an effective approach to offshore pipeline protection for impact loads. However, few studies address the influences of inherent soil spatial variabilities on failure behaviour of soil covers and pipelines, causing deviations. Therefore, a random field-large deformation finite element analysis framework is developed to explore the failure mechanisms of buried pipelines in spatially varying soils. The failure mode of soil cover is conformed to a local mode, where the failure path is insensitive to soil variability. The failure mechanism of pipelines depends on the competition mechanism between soil strengths and pipe-soil interactions, based on which two typical failure modes are summarized. Soil variability not only aggravates the impact damage but also stimulates the diversity of structural responses. Correlations between probabilistic damage degrees and multiple influential factors are discussed. Further, inspired by the principle of energy dissipation, an integrated quantitative risk assessment model is derived to reveal the failure risk evolution, where uncertainties from soil variabilities and structure-related factors are considered. The latter shows a significant influence, which may pose an additional failure probability of over 50 %. Different safety design approaches are compared, and spatial failure probability surfaces are configured for burial depth determination.

埋设是保护近海管道免受冲击载荷的有效方法。然而，很少有研究涉及土壤固有的空间变化对土壤覆盖层和管道破坏行为的影响，从而导致偏差。因此，本文建立了一个随机场-大变形有限元分析框架，以探讨埋地管道在空间变化土壤中的破坏机制。土壤覆盖层的破坏模式符合局部模式，破坏路径对土壤变化不敏感。管道的破坏机制取决于土壤强度之间的竞争机制和管道与土壤之间的相互作用，在此基础上总结出两种典型的破坏模式。土壤的多变性不仅会加剧冲击破坏，还会刺激结构响应的多样性。讨论了概率破坏程度与多种影响因素之间的相关性。此外，在能量耗散原理的启发下，得出了一个综合定量风险评估模型，以揭示破坏风险的演变，其中考虑了土壤变异和结构相关因素的不确定性。后者具有重大影响，可能造成超过 50% 的额外失效概率。比较了不同的安全设计方法，并为确定埋深配置了空间失效概率曲面。

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