Applied Ocean Research最新文献

Protection of custom satellite antennas for deep-sea monitoring probes: Insights from the SONDA project

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-23 DOI: 10.1016/j.apor.2025.104575

T. Matos , H. Dinis , C.L. Faria , M.S. Martins

This study presents the development and testing of satellite antennas for the SONDA probe, an innovative deep-sea monitoring system designed to be deployed by high-altitude balloons. The probe descends to the deep ocean, resurfaces, and transmits data while functioning as a drifter. The project faced unique design constraints, including the need for low-cost materials and lightweight construction for balloon deployment. These constraints ruled out traditional hermetic housings, necessitating alternative solutions for antenna protection. The work focused on custom ceramic patch antennas and their performance under various protective coatings, which affected the antennas’ resonance and gain. Thinner layers effectively protected the antennas from high-pressure conditions and water ingress, maintaining functionality. Experiments on antenna height revealed optimal positioning above the water surface to minimize wave-induced signal interference. Hyperbaric chamber tests validated the mechanical integrity and functionality of the antennas under pressures equivalent to depths of 1500 m Antenna characterization techniques were employed in an anechoic chamber to validate antenna performance with the coating and to assess their correct operation after the hyperbaric tests. Field deployments demonstrated the antennas’ capability to transmit data after diving. Challenges included communication delays, corrupted data, and mechanical vulnerabilities in materials. The findings emphasize the importance of rigorous mechanical design, material selection, and system optimization to ensure reliability in marine environments. This work advances the development of low-cost, lightweight, and modular probes for autonomous ocean monitoring, with potential applications in long-term drifter studies, real-time marine monitoring and oceanographic research.

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引用次数: 0

Lateral bearing characteristics of modified suction caisson embedded in layered soil

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-21 DOI: 10.1016/j.apor.2025.104572

Yukun Zhang , Yang Chen , Dayong Li , Xinyu Hou , Ying Lai

Model tests and numerical simulations were conducted to investigate the lateral bearing characteristics of a modified suction caisson (MSC) in layered soil. The impacts of the loading eccentricity and the soil layer distribution on the lateral bearing capacity, rotation point position variation and soil deformation behavior were studied. Results indicate The MSC lateral bearing capacity in sand-over-clay is greater than that in clay-over-sand. In both sand-over-clay and clay-over-sand, the MSC bearing capacities were all found to increase with increasing the sand layer thickness. During lateral loading, the MSC rotation point continuously move downward and finally reaches the stable position in the limit state. The final embedded depths of the rotation position under various soil types are as follows: clay-over-sand is the deepest, sand is next, sand-over-clay is the next, and clay is the shallowest. In addition, the three-dimensional soil deformation zones around the MSC were obtained. The three-dimensional elliptic shaped soil deformation strain wedge boundary surface at the front side of the MSC along the loading direction extends linearly from MSC internal compartment outer wall (with the embedded depth where the rotation point is located) diagonally upward to the topsoil surface. The boundary of the deformed topsoil surface at the front side of the MSC along the loading direction can be fitted as an elliptic function. Based on the test and numerical results, solutions calculating the lateral bearing capacity of the MSC in layered soil were proposed using the limit equilibrium method and earth pressure theory. Results show that the proposed solution can well predict the lateral bearing capacities for the MSC and the TSC in sand, clay and layered soil.

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引用次数: 0

Analysis of vibration characteristics of deep-sea mining risers under emergency disconnection state

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-20 DOI: 10.1016/j.apor.2025.104548

Jiaqi Han , Zhen Wang

The extreme marine environment poses a significant threat to deep-sea mining operations. For the sake of security, the jack-up diving platform and riser system are still deployed in the sea, and the emergency evacuation of personnel and mining vessels is one of the common coping strategies. To address the issue of mineral particles naturally settling and stratifying under the influence of gravity in the riser during emergency state, which leads to the nonuniform distribution of the tension of the riser, a simplified mathematical model for the transverse vibration of the segmented riser is established and solved by the new method based on perturbation. The analytical expression of the natural frequencies and the corresponding mode functions of the transverse vibration of the riser under the emergency state is theoretically given. The change in the vibration characteristics of the risers in emergency and operation states is compared and analyzed. The influence of the concentration of mineral particles in the riser in operation state and the concentration of mineral particles in the riser under emergency disconnection state and the density of mined mineral particles on the vibration characteristics of the riser is analyzed. The results indicate that the natural frequencies of segmented risers increase under emergency conditions, with variations within 10% of the operational frequencies. The first-order frequency exhibits the most significant change. The upper segment riser vibrates more violently than the bottom segment riser, and every ventral point in each order of mode moves to the negative x-axis direction compared with the operation state. When the concentration of mineral particles in the riser under operation state increases, the natural frequency of each order decreases. When the concentration of mineral particles in the bottom mineral segment riser of the emergency state increases, the first order and the second order natural frequencies will increase, the third order and the sixth order natural frequencies will first decrease and then increase, and the fourth order and the fifth order natural frequencies will first increase and then decrease. When the mineral density increases, the natural frequency of each order will decrease. Each ventral point in each mode moves regularly with the change of mineral particle density and concentration.

极端的海洋环境对深海采矿作业构成重大威胁。为了安全起见，自升式潜水平台和立管系统仍然部署在海中，人员和采矿船的紧急撤离是常见的应对策略之一。针对紧急状态下立管在重力作用下矿物颗粒自然沉降分层，导致立管张力分布不均匀的问题，建立了分段立管横向振动简化数学模型，并采用基于扰动的新方法进行求解。从理论上给出了紧急状态下立管横向振动的固有频率和相应模态函数的解析表达式。对比分析了紧急状态和运行状态下立管振动特性的变化。分析了运行状态下立管矿粒浓度、紧急断开状态下立管矿粒浓度以及矿粒密度对立管振动特性的影响。结果表明，在紧急状态下，分段立管的固有频率会增加，变化幅度在工作频率的 10%以内。一阶频率的变化最为显著。与运行状态相比，上分段立管的振动比下分段立管更剧烈，各阶模态的每个腹点都向负 x 轴方向移动。当运行状态下的立管中矿物颗粒浓度增加时，各阶固有频率降低。当应急状态下底部矿段立管中的矿物颗粒浓度增加时，第一阶和第二阶固有频率将增加，第三阶和第六阶固有频率将先降低后增加，第四阶和第五阶固有频率将先增加后降低。当矿物质密度增加时，各阶固有频率会降低。每个模式中的每个腹点都会随着矿物颗粒密度和浓度的变化而有规律地移动。

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引用次数: 0

Severe slugging mitigation by utilizing the active use of choke control valve

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-19 DOI: 10.1016/j.apor.2025.104547

V Banjara , C Avila , D Murugavel , E Pereyra

One of the common flow assurance issues in offshore production facilities is riser-based severe slugging. Severe slugging is a cyclic process that occurs in the late life of reservoirs when there is not enough energy available in the system to push the liquid out of the riser. A novel technique is proposed in this study to mitigate this issue. Unlike the conventional choking techniques, where additional backpressure is applied on the riser to mitigate severe slugging, the proposed technique involves utilizing the active use of either the choke control valve located downstream of the riser in a pipeline-riser system or the separator gas control valve. This new technique can be utilized in brownfields where pipeline pressure measurement installed for feedback control loops is not feasible. The main advantage of the new technique is that it can use the available measurements and equipment (gas control valve and pressure sensors) available in a regular topside facility. In this study, an algorithm is developed that can determine the required valve operation sequence (amplitude and frequency) of the choke control valve based on the natural slugging frequency. The objective is the mitigation of the severe slugging, which minimizes imposing the additional backpressure on the pipeline-riser system. Proof of concept of the proposed technique demonstrated on a large-scale facility using the transient simulations. The results of the transient simulations using OLGA show that the active use of the choke control valve does affect the severe slugging characteristics. The results show that the valve sequence can either mitigate severe slugging or make it worse depending on the selection of the valve operation sequence. Therefore, determining the correct valve sequence is very critical. To investigate further, another case study has been presented, where the results from the algorithm developed in-house for the choke control valve operation sequence were tested using OLGA simulations. These simulation results show that the proposed technique is successful in providing a unique combination of choke control valve opening frequency and amplitude, which will mitigate the severe slugging without increasing the additional backpressure on the system.

海上生产设施中常见的流量保证问题之一是立管严重堵塞。严重堵塞是一个循环过程，发生在储油层的后期，当系统中没有足够的能量将液体推出隔水管时就会出现。本研究提出了一种新技术来缓解这一问题。传统的扼流技术是在隔水管上施加额外的背压，以缓解严重的堵塞现象，而本研究提出的技术则不同，它是利用管道-隔水管系统中位于隔水管下游的扼流控制阀或分离器气体控制阀的积极作用。这种新技术可用于无法安装用于反馈控制回路的管道压力测量装置的棕色区域。新技术的主要优势在于，它可以利用常规顶层设施中的现有测量和设备（气体控制阀和压力传感器）。本研究开发了一种算法，可根据自然抽吸频率确定所需的扼流控制阀操作顺序（振幅和频率）。其目的是缓解严重的堵塞，从而最大限度地减少对管道-上升器系统施加额外的背压。利用瞬态模拟在大型设施上演示了所提技术的概念验证。使用 OLGA 进行的瞬态模拟结果表明，主动使用扼流控制阀确实会影响严重堵塞特性。结果表明，根据阀门操作顺序的选择，阀门顺序既可以减轻严重堵塞现象，也可以使其恶化。因此，确定正确的阀门顺序非常关键。为了进一步研究，还提出了另一个案例研究，使用 OLGA 仿真测试了内部开发的扼流控制阀操作顺序算法的结果。这些模拟结果表明，所提出的技术能够成功提供独特的扼流控制阀开启频率和振幅组合，从而在不增加系统额外背压的情况下缓解严重堵塞。

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引用次数: 0

Assessment of navigable water depth reliability in the Port of Singapore on the basis of AIS

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-19 DOI: 10.1016/j.apor.2025.104574

Zeming Li , Qizhi Zhuang , Hengyong Chu , Shanlin Gao , Liang Cheng , Jian Cheng , Zhixin Duan , Qingren Xue , Yunchang Yao , Deliang Chen , Yaping Qi , Manchun Li

Vessel groundings can be harmful to people and the environment. Draught in Automatic Identification System (AIS) data can help vessels avoid grounding incidents. However, AIS data often contain redundancies and errors. Vessel draught is not effectively utilized. This study aims to design a reliability assessment method based on the characteristics of AIS data to calculate reliable navigable water depth. The Port of Singapore is selected as the study area to generate navigable water depth. The proposed method calculates navigable water depth in grids and assesses its reliability. The assessment considers factors, such as the dispersion of a vessel’s draught, completeness of trajectories, type of vessels, and Vessel voyage data. A navigable water depth product can be obtained through data cleaning and reliability assessment. Results demonstrate the effectiveness of the proposed method in calculating navigable water depth and assessing reliability. Specifically, the method performs well in areas whose water depth is <25 m, including wharves, inner harbor channels, and anchorages. The data are compared with other depth prediction methods, and the error between it and the charts is relatively small. The obtained navigable water depth is generally less than the chart depth and meets the requirements for safe navigation while optimizing the utilization of water depth in the port. The methodology has also been applied in other areas. Overall, utilizing AIS data to calculate and assess the reliability of navigable water depth provides valuable information for enhancing navigational safety and optimizing port water depth utilization. It also makes draught in AIS effective.

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引用次数: 0

Influence of variation in dynamic parameters of the flexible hydrofoil on energy harvesting performance

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-19 DOI: 10.1016/j.apor.2025.104577

Yuzhi Yao, Chaoyong Zong, Jiaming Jia, Jianan Xu

The flexible hydrofoil represents a promising tidal energy harvesting device, known for its environmentally friendly attributes. Understanding the intricacies of its energy harvesting mechanism and analyzing the impacts of key parameters are essential prerequisites for achieving refined design and optimization. In pursuit of this objective, this paper conducts a comprehensive numerical analysis. A numerical model is developed, focusing on a flexible tail hydrofoil that operates under the fully-passive model and incorporates the crucial aspect of fluid-structure interaction (FSI). With the established model, such as heave damping, pitch damping, heave elasticity coefficient, and pitch elasticity coefficient, various dynamic parameters are delved into the influence on energy harvesting performance. The FSI phenomenon occurring between the hydrofoil and the fluid flow are analyzed. Due to the influence of the tail flexibility of the oscillating foil, the trailing edge vortex is generated and the intensity increases. This phenomenon affects the generation and development of the leading-edge vortex, the magnitude of the lift and the synchronization of motion. Through this optimization process, the oscillating hydrofoil attained an average efficiency of 37.8 % and an average energy harvesting power coefficient of 1.56.

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引用次数: 0

Centrifuge shaking table tests on the seismic performance of revetment breakwater on reclaimed coral sand 珊瑚砂填海护岸防波堤抗震性能离心振动台试验

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-18 DOI: 10.1016/j.apor.2025.104571

Yunyi Li, Bin Hu-Yan, Yulong Liao, Jian-Min Zhang, Rui Wang

Revetment breakwaters on reclaimed coral sand have demonstrated vulnerability to seismic damage during strong earthquakes, wherein soil liquefaction has been identified as a substantial contributor. Based on the results of three centrifuge shaking table tests, this study investigates the characteristic seismic response of revetment breakwater on reclaimed coral sand and the influence of soil liquefaction. The basic mechanical properties of reclaimed coral sand were measured using undrained triaxial and hollow cylinder torsional shear tests. The centrifuge test results indicate that liquefaction of coral sand can result in significant displacement and even failure of revetment breakwaters, encompassing: (a) tilting, horizontal displacement, and settlement of the crest wall; (b) seismic subsidence in the foundation and backfill. The liquefaction consequence of the reclaimed coral sand increased with a decrease in soil density and rise in sea water level (SWL). Post-earthquake rapid reinforcement measure via sandbags is found to be effective in limiting excess pore pressure buildup in foundation soil and structure deformation under a second shaking event. Based on the test results, the effectiveness of current simplified design procedures in evaluating the stability and deformation of breakwaters in coral sand is assessed. When substantial excess pore pressure generation and liquefaction occur within the backfill and foundation coral sand, the pseudo-static and simplified dynamic methods are inadequate in assessing the stability and deformation of the breakwater.

在强烈地震中，填海珊瑚沙上的护岸防波堤很容易受到地震破坏，而土壤液化被认为是造成地震破坏的主要因素。根据三次离心振动台试验的结果，本研究调查了珊瑚砂填海护岸防波堤的地震响应特征以及土壤液化的影响。通过不排水三轴试验和空心圆筒扭剪试验测量了填海珊瑚砂的基本力学性能。离心机试验结果表明，珊瑚砂的液化会导致护岸防波堤发生显著位移，甚至失效，包括：（a）顶墙倾斜、水平位移和沉降；（b）地基和回填土的地震沉降。随着土壤密度的降低和海水水位（SWL）的上升，填海珊瑚砂的液化后果也随之增加。通过沙袋采取的震后快速加固措施可有效限制地基土壤中过量孔隙压力的积聚以及第二次地震时的结构变形。根据测试结果，评估了当前简化设计程序在评估珊瑚砂防波堤稳定性和变形方面的有效性。当回填土和地基珊瑚砂中产生大量过剩孔隙压力和液化时，伪静力法和简化动力法不足以评估防波堤的稳定性和变形。

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引用次数: 0

Residual stress in thick titanium-alloy butt-welded plates and effect of hydrogen on fatigue crack propagation

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-17 DOI: 10.1016/j.apor.2025.104543

Jinhui Jiang , Lingyun Wang , Zhaoyi Shi , Liangbi Li

Pressure-resistant titanium-alloy shells are typically fabricated using welding assemblies, making them vulnerable to hydrogen-induced cracking. Consequently, it is of enormous importance to study the crack initiation and fatigue crack propagation of titanium-alloy thick-plate butt welding under the combined action of hydrogen and welding residual stress. In this study, the X-ray non-destructive testing method was used to examine the sheet metal, and the residual stress was numerically calculated. Subsequently, the hydrogen concentration in different regions of a TC4 titanium-alloy butt-welded plate was measured using the thermal conductivity method. Finally, a VUMAT subroutine was developed to simulate the crack initiation and propagation. This enabled us to study the crack initiation and fatigue crack propagation of a TC4 titanium-alloy butt-welded plate under the coupling of hydrogen and residual stress.

引用次数: 0

DSM-Net: A multi-scale detection network of sonar images for deep-sea mining vehicle

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-17 DOI: 10.1016/j.apor.2025.104551

Xinran Liu , Jianmin Yang , Wenhao Xu , Qihang Chen , Haining Lu , Yu Chai , Changyu Lu , Yulong Xue

Deep-sea mining vehicles (DSMVs) play a crucial role in deep-sea mining operations, requiring high-precision, real-time detection of seabed rocks and terrain of varying scales to ensure safe navigation and operation. However, the complexity of multi-scale seabed terrains, along with the low resolution and high noise levels in sonar images, makes accurate real-time detection a challenge. To address these issues, DSM-Net, a multi-scale terrain detection network specifically designed for deep-sea mining, is proposed. DSM-Net integrates several innovative modules: the Tri-Scale Attention Module (TSA) extracts multi-scale features and reduces noise interference, the Partial-Dynamic Module (PDM) improves inference speed, and the ASFF* detection head incorporates an additional small-target detection layer. Furthermore, an adaptive weighting function, Adaptive Difficulty Loss (ADL), is introduced to handle the imbalance in the number of targets across different scales in actual seabed environments. DSM-Net was evaluated on the DSMSD dataset, showing a 2.16 % improvement in [email protected]:0.95 and an 18.75 % reduction in inference time compared to the YOLOv8 baseline, striking an effective balance between detection speed and accuracy. In sea trials, DSM-Net contributed to path planning and obstacle avoidance, proving its practical engineering value.

深海采矿车（DSMV）在深海采矿作业中发挥着至关重要的作用，需要对不同尺度的海底岩石和地形进行高精度的实时探测，以确保导航和作业安全。然而，多尺度海底地形的复杂性，以及声纳图像的低分辨率和高噪声水平，使得精确的实时探测成为一项挑战。为解决这些问题，我们提出了专为深海采矿设计的多尺度地形探测网络 DSM-Net。DSM-Net 集成了多个创新模块：三尺度关注模块 (TSA) 可提取多尺度特征并减少噪声干扰；部分动态模块 (PDM) 可提高推理速度；ASFF* 检测头集成了额外的小目标检测层。此外，还引入了自适应加权函数--自适应难度损失（ADL），以处理实际海底环境中不同尺度目标数量不平衡的问题。DSM-Net 在 DSMSD 数据集上进行了评估，与 YOLOv8 基线相比，[email protected]:0.95提高了 2.16%，推理时间缩短了 18.75%，在探测速度和准确性之间取得了有效平衡。在海上试验中，DSM-Net 为路径规划和避障做出了贡献，证明了其实际工程价值。

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引用次数: 0

ANN and blockchain-orchestrated decentralized data-driven analytical framework for ship fuel oil consumption

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-04-17 DOI: 10.1016/j.apor.2025.104553

Mihir Parekh , Nilesh Kumar Jadav , Sudeep Tanwar , Giovanni Pau , Fayez Alqahtani , Amr Tolba

In maritime operations, advanced technologies have paved the way for predictive analytics to optimize energy consumption. In this research, we introduce an AI and blockchain-assisted intelligent and secure framework for predicting energy consumption in ships to enhance efficiency and sustainability. In this context, we used a standard energy consumption dataset comprising CO

_{2}

emissions and energy consumption features; therefore, we first employed a regression model that predicted CO

_{2}

emissions in ships. Based on the prediction, we create the target labels in the dataset, i.e., ship with poor engine (1) and ship with good engine (0). Subsequently, we applied decentralized training on the dataset using federated learning (FL) for the binary classification problem. We utilized an artificial neural network (ANN) in FL that efficiently categorized the ships based on their energy consumption features. Furthermore, we considered a tampered-proof technology, i.e., blockchain technology, that confronts data tampering attacks on FL-trained weights. In that context, we developed a smart contract that ensures valid FL-trained weights get shared with FL clients and the global model. To guarantee the outperformance of the proposed framework, we assess it by considering different evaluation metrics, such as FL client’s training accuracy (98.74%), training loss (0.094), validation curve, regression error rate (

\approx

24.15–32.12), and blockchain’s transaction and execution cost (

\approx

50000–260000). The synergy of AI and blockchain highlights their combined impact on revolutionizing energy consumption prediction in the maritime industry. The proposed framework not only refines predictive accuracy but also ensures the confidentiality and integrity of the predicted data.

在海事运营中，先进技术为优化能源消耗的预测分析铺平了道路。在本研究中，我们介绍了一种人工智能和区块链辅助的智能安全框架，用于预测船舶能耗，以提高效率和可持续性。在此背景下，我们使用了一个由二氧化碳排放量和能源消耗特征组成的标准能源消耗数据集；因此，我们首先采用了一个回归模型来预测船舶的二氧化碳排放量。根据预测结果，我们在数据集中创建了目标标签，即发动机不良的船舶（1）和发动机良好的船舶（0）。随后，我们使用联合学习（FL）对数据集进行分散训练，以解决二元分类问题。我们在 FL 中使用了人工神经网络 (ANN)，可根据船舶的能耗特征对其进行有效分类。此外，我们还考虑了一种防篡改技术，即区块链技术，该技术可应对对 FL 训练的权重的数据篡改攻击。在此背景下，我们开发了一种智能合约，确保有效的 FL 训练权重能够与 FL 客户和全局模型共享。为了保证所提框架的卓越性能，我们通过考虑不同的评估指标对其进行了评估，例如 FL 客户端的训练准确率（98.74%）、训练损失（0.094）、验证曲线、回归错误率（≈ 24.15-32.12）以及区块链的交易和执行成本（≈ 50000-260000）。人工智能和区块链的协同作用凸显了它们对海运业能耗预测革命的共同影响。所提出的框架不仅提高了预测的准确性，还确保了预测数据的保密性和完整性。

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引用次数: 0