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Experiment and modeling of submarine emergency rising motion using free-running model
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2024.100641
Jooho Lee, Seonhong Kim, Jihwan Shin, Jaemoon Yoon, Jinheong Ahn, Minjae Kim
Development of submarine and its safe operational envelope requires an understanding of motion characteristics including emergency rising motion. In this study, the emergency rising motion is investigated using submarine free-running model equipped with ballast systems. The emergency rising test was conducted according to the initial vehicle speed, yaw rate, depth, ballast water discharge ratio and time interval between bow and stern ballast systems. Experimental results reveal that the maximum pitch angle before surface is affected by initial velocity and the operation conditions of ballast systems. In addition, excessive roll occurs after the surface when the submarine passes through the water surface at a negative pitch angle. Furthermore, the system parameters that comprise the emergency rising model are estimated using the collected test data. The identified model is verified by comparing emergency rising simulation with the free-running model test results.
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引用次数: 0
A comprehensive review of foundation designs for fixed offshore wind turbines 固定式海上风力发电机基础设计综述
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2025.100643
Yun-jae Kim , Jin Seok Lim , Hae Jong Kim , Sung-Woong Choi
In the present study, technical challenges and their corresponding solutions for each type of foundation—gravity-based, monopile, jacket, tripod, and suction bucket—used in wind turbines were addressed with consideration to different water depths. Along with presenting challenges and their solutions for each foundation, the present study proposed optimizing solutions and methods for addressing these challenges, including numerical approaches and empirical methods derived from field testing. These include enhancing structural stability, improving installation efficiency, and utilizing advanced structural analysis techniques to predict and mitigate environmental impacts. Finally, research cases demonstrating improvements in foundations through shape modifications are summarized. This paper focuses on addressing and proposing an optimal design approach to achieve cost reduction, improved stiffness, and weight minimization. Notably, hybrid foundations incorporating friction wheels achieved a 300% increase in ultimate bearing capacity, while optimization techniques accounting for environmental loads resulted in approximately a 38.24% reduction in foundation weight.
本文针对风力发电机组中使用的重力式基础、单桩式基础、夹套式基础、三脚架式基础、吸力桶式基础等不同类型的基础,针对不同的水深,分析了其技术难点及解决方案。除了提出每个基础面临的挑战及其解决方案外,本研究还提出了应对这些挑战的优化解决方案和方法,包括数值方法和来自现场测试的经验方法。这些措施包括增强结构稳定性,提高安装效率,以及利用先进的结构分析技术来预测和减轻环境影响。最后,总结了通过形状修改改善地基的研究案例。本文的重点是解决和提出一个优化的设计方法,以实现成本降低,提高刚度和重量最小化。值得注意的是,结合摩擦轮的混合地基的极限承载能力提高了300%,而考虑环境载荷的优化技术则使地基重量减少了38.24%。
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引用次数: 0
Adaptive neural network fault-tolerant sliding mode control for ship berthing with actuator faults and input saturation
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2025.100644
Son Tung Vu , Thai Duong Nguyen , Hai Van Dang , Van Suong Nguyen
This paper develops a robust controller for automatic ship berthing subjected to actuator faults, input saturation, modeling uncertainties, and external disturbances. First, sliding mode control (SMC) is used as a core controller to provide robust features for the ship berthing system. Second, fault-tolerant control (FTC) is combined with the controller to face the actuator faults. Third, the radial basis function (RBF) neural network is employed to approximate the modeling uncertainties while the effect of external disturbances is compensated by an adaptive control technique. In addition, an anti-saturation auxiliary system is conducted to deal with the input saturation for physical limitations of the actuators. Finally, numerical simulation and comparison of the results with the other control approaches are carried out to highlight the advantages of the proposed controller.
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引用次数: 0
Effect of notch shape on the fracture toughness behavior
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2025.100646
Jiseung Lee , Wonjun Jo , Junseok Seo , Gyubaek An
This study evaluates the effect of notch shape on the fracture toughness of a 500 MPa base material designed for liquefied carbon dioxide storage tanks. This study specifically focuses on assessing the crack tip opening displacement (CTOD) values for different notch shapes, including fatigue pre-cracks (R = 0.025 mm) and electrical discharge machining (EDM) notches (R = 0.07 mm and R = 0.15 mm). CTOD tests were conducted over a temperature range of −55 °C to −140 °C. The results revealed that as the notch radius increased, the degree of stress concentration decreased, leading to an increase in fracture toughness. In temperature-dependent tests, CTOD values consistently decreased as the temperature decreased, with EDM notches exhibiting a lower rate of fracture toughness reduction compared to fatigue pre-cracks, which is attributed to differences in the degree of stress concentration. Scanning electron microscopy analysis of the fracture surfaces revealed the reason for significant differences in CTOD values and fracture behaviors between fatigue pre-crack and EDM notches, particularly at −140 °C, a temperature below the ductile to brittle transition temperature. This study suggests that EDM notches, especially with radii of 0.07 mm and 0.15 mm, can effectively replace fatigue pre-cracks in CTOD evaluations, particularly at temperatures above the transition temperature, offering a more efficient method for assessing fracture toughness in cryogenic environments.
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引用次数: 0
Horizontal plane course-stability and manoeuvres of a twin-screw surface combatant depending on appendage dimensions 依赖附件尺寸的双螺旋水面战斗舰的水平面航向稳定性和机动
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2025.100655
Dong-Jin Kim, Haeseong Ahn, Dong Jin Yeo
In this study, powering and manoeuvring performance of a twin-screw surface combatant, ONR tumblehome (ONRT), are estimated through towing tank captive model tests, and influences of appendage dimensions on its course-stabilities and manoeuvres are investigated by system-based simulation techniques. At first, resistance and propulsion tests are carried out at Froude numbers up to 0.4 in the towing tank of Korea Research Institute of Ships and Ocean Engineering (KRISO) so that its full-scale powering performance can be considered in the present simulation model. In particular, the residuary resistance is significantly affected by patterns of hull generated waves. Secondly, horizontal planar motion mechanism (HPMM) tests are performed to derive hydrodynamic coefficients in surge, sway, and yaw directions. By using 3-DoF modular-type models, turn and zig-zag manoeuvres are simulated, and simulations are validated with existing benchmark free-run model tests. Sway-yaw coupled linear whole ship models are also established in order to assess a straight-line stability of a rudder-fixed ONRT whole ship. Linear hydrodynamic coefficients are decomposed into hull and appendage components so that influences of appendage dimensions on ship manoeuvres can be analyzed in more detail. When the rudder area is enlarged or reduced, the coefficient and the location of a centerline skeg are redesigned under the constraint straight-line stabilities are identical. For one original ONRT and two modified ships, turn and zig-zag manoeuvres are simulated by linear whole ship models. Even though straight-line stabilities are identical, the turning diameter is decreased while zig-zag overshoot angles are increased with increasing rudder area. To ensure sufficient manoeuvrabilities of such a twin-screw ship, careful attentions should be paid to design of a centerline skeg and rudders.
本文通过拖曳坦克自备模型试验,对双螺杆水面作战舰艇“滚落之家”(ONR tumblehome, ONRT)的动力性能和机动性能进行了评估,并采用系统仿真技术研究了附件尺寸对其航向稳定性和机动性能的影响。首先,在韩国船舶海洋工程研究院(KRISO)的拖曳舱中,在弗劳德数高达0.4的情况下进行阻力和推进试验,以便在本仿真模型中考虑其全尺寸动力性能。特别是,船体产生的波浪模式对剩余阻力有显著影响。其次,进行了水平平面运动机构(HPMM)试验,得到了浪涌、摇摆和偏航方向的水动力系数。采用三自由度模块化模型,仿真了转向和之字形机动,并与已有的基准自由运行模型试验进行了验证。为了评估定舵ONRT整船的直线稳定性,建立了横摆耦合线性全船模型。将线性水动力系数分解为船体和附属物两部分,以便更详细地分析附属物尺寸对船舶操纵性能的影响。当舵面积增大或减小时,在直线稳定性相同的约束条件下,重新设计了系数和中心线偏差的位置。针对一艘原舰和两艘改进型舰,采用线性全船模型对转弯和之字形操纵进行了仿真。尽管直线稳定性相同,但随着舵面积的增加,转弯直径减小,而之字形超调角增大。为了保证这种双螺杆船有足够的操纵性,在设计中线舵和舵时应特别注意。
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引用次数: 0
Machine learning-based optimal value calculation for welding variables in AR training 基于机器学习的AR训练中焊接变量最优值计算
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2025.100652
Chang Sub Song , Jong-Ho Nam
Currently, the shipbuilding industry is experiencing a surge in orders due to the rising demand for eco-friendly ships, necessitating the optimal use of available resources for production. However, the production workforce has not fully recovered to the level required to meet these increased orders following large-scale industry restructuring. In particular, there is a shortage of highly skilled welders, and concerns are growing about the transfer of expertise due to an aging workforce and a lack of younger workers. Shipbuilders worldwide face similar challenges and are exploring various methods to transfer the tacit knowledge of skilled welders to less experienced workers, which has introduced unforeseen challenges. In this study, we develop a machine learning algorithm that suggests the optimal values of key welding variables for an AR-based welding training system designed to assist less skilled workers. We collected welding data from highly skilled workers using the FCAW (Flux-Cored Arc Welding) technique, which is commonly employed in the shipbuilding process. The welding variables that represent tacit knowledge were identified and trained using the Extra Trees Regressor model. Subsequently, a welding AR training system was implemented, allowing the trained model to guide users on the optimal values for welding variables. Finally, the effectiveness of this system in training welders was verified at a shipyard technical training center.
目前,由于对环保船舶的需求不断增加,造船业的订单量急剧增加,因此必须充分利用现有资源进行生产。然而,在大规模行业重组之后,生产劳动力还没有完全恢复到满足这些增加的订单所需的水平。特别是,高技能焊工短缺,而且由于劳动力老龄化和年轻工人缺乏,人们越来越担心专业知识的转移。世界各地的造船商都面临着类似的挑战,他们正在探索各种方法,将熟练焊工的隐性知识传授给经验不足的工人,这带来了意想不到的挑战。在本研究中,我们开发了一种机器学习算法,该算法为基于ar的焊接培训系统提供关键焊接变量的最佳值,旨在帮助技能较低的工人。我们收集了使用FCAW(药芯弧焊)技术的高技能工人的焊接数据,这种技术通常用于造船过程。使用额外树回归模型对代表隐性知识的焊接变量进行识别和训练。随后,实现了焊接AR训练系统,训练后的模型可以指导用户选择焊接变量的最优值。最后,以某船厂技术培训中心为例,验证了该系统在焊工培训中的有效性。
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引用次数: 0
Performance analysis of Flettner rotor considering Marine wind profile and ship installation using CFD 考虑海上风廓线和船舶安装的Flettner转子性能CFD分析
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2025.100653
SeongMo Yeon, Chang Seop Kwon, Yoo-Chul Kim, Kwang Soo Kim, Yeon Gyu Kim, Yun Ho Kim, Hee Jin Kang
The study investigated a Flettner rotor performance on a hull, analyzing design modifications and wind profiles for a small catamaran which designed by KRISO for the K-Energy Observer platform was analyzed. The rotor mounted on the hull showed a nearly 48% performance degradation in lift coefficient compared to the standalone rotor due to the disturbed flow by the hull at spin ratios 3–4. Two design factors were examined to improve performance: foundation shape and bottom configuration of the rotor. A square foundation shape showed relatively better improvement but it was not significant. On the other hand, it was found that the rotating end plate significantly improved thrust, achieving up to 80% of the standalone rotor’s performance. Comparing uniform and Norwegian Petroleum Directorate (NPD) wind profiles, the NPD profile showed a 12% improvement due to stronger winds at the rotor’s upper section. The study also compared performance under different wind directions and it showed a 20% increase at 30° and 18% at 60° for the original configuration. In contrast, the rotating end plate configuration showed a 6% decrease at 30° but a 10% increase at 60°. However, overall performance improvement was observed in the rotating end plate configuration with increases of 12%, 34%, and 44% for 30°, 60° and 90° compared to the original configuration. Additionally, under a 5° inclined hull condition, performance decreased by 21% for the original configuration but only 13% for the rotating end plate configuration, which highlighted the design’s effectiveness in mitigating performance loss.
该研究调查了安装在船体上的 Flettner 转子的性能,分析了 KRISO 为 K-Energy Observer 平台设计的小型双体船的设计修改和风廓线。与独立转子相比,安装在船体上的转子升力系数降低了近 48%,原因是在旋转比为 3-4 时,船体会扰动气流。为提高性能,研究了两个设计因素:基础形状和转子底部配置。方形地基形状的改善效果相对较好,但并不显著。另一方面,研究发现旋转端板显著提高了推力,可达到独立转子性能的 80%。在比较了均匀风和挪威石油局(NPD)风廓线后发现,由于转子上部的风力较强,NPD 风廓线的性能提高了 12%。研究还比较了不同风向下的性能,结果表明,原始配置在 30° 风向下的性能提高了 20%,在 60° 风向下提高了 18%。相比之下,旋转端板配置在 30° 时性能降低了 6%,但在 60° 时提高了 10%。不过,与原始配置相比,旋转端板配置在 30°、60° 和 90°时的总体性能分别提高了 12%、34% 和 44%。此外,在倾斜 5° 的船体条件下,原始配置的性能降低了 21%,而旋转端板配置的性能仅降低了 13%,这凸显了该设计在减少性能损失方面的有效性。
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引用次数: 0
The extended modified Logvinovich model: Application to the water entry of two-dimensional wedges
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2024.100631
Yang Zhang , Se-Myong Chang , Deuk-Joon Yum
A planing craft is one of the most commonly used types for small high-performance vessels since it helps to mitigate the severe viscous friction between the ship hull and water. Therefore, it is essential to develop methods for quickly and accurately estimating the running attitude during the early design phase and in actual operational conditions. We propose the Extended Modified Logvinovich Model (EMLM) for water entry to address the flow separation problem when a wedge-shaped hull enters the free surface during motion. Utilizing a two-dimensional approximation, we analyzed the fundamental potential flow through mathematical techniques for unsteady flow. As a verification, we calculated the dynamic vertical force coefficient compared with CFD(computational fluid dynamics) based on BEM(boundary element method) and an analytic similarity solution, where the results demonstrated good agreement with experimental data for validation.
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引用次数: 0
YOLO-ESFM: A multi-scale YOLO algorithm for sea surface object detection YOLO- esfm:海面目标检测的多尺度YOLO算法
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2025.100651
Maochun Wei , Keyu Chen , Fei Yan , Jikang Ma , Kaiming Liu , En Cheng
Environmental perception and object detection are pivotal research topics in the marine domain. The sea surface presents unique challenges, including harsh weather conditions, wave interference, and multi-scale targets, often resulting in suboptimal detection results. To address these issues, we present an innovative solution: the integration of the Efficient Scale Fusion Module (ESFM) into the advanced YOLO architecture, resulting in the enhanced model, YOLO-ESFM. The ESFM serves as both the backbone and detection head of the network, significantly improving performance compared to the baseline models in YOLOv5s, YOLOv7-tiny, and YOLOv7. Furthermore, to tackle the limitations of the CIOU in YOLOv7, we introduce an improved method, ZIOU, which has been rigorously evaluated and proven effective on the Sea Surface Target Dataset. Comparative studies demonstrate that YOLO-ESFM not only maintains efficiency in terms of parameters and FLOPs but also surpasses YOLOv7 in detection accuracy on both the Sea Surface Target Dataset and the PASCAL VOC 07+12 Dataset.
环境感知和目标检测是海洋领域的关键研究课题。海面面临着独特的挑战,包括恶劣的天气条件、波浪干扰和多尺度目标,通常会导致不理想的探测结果。为了解决这些问题,我们提出了一种创新的解决方案:将高效规模融合模块(ESFM)集成到先进的YOLO架构中,从而产生增强模型YOLO-ESFM。ESFM同时充当网络的骨干和检测头,与YOLOv5s、YOLOv7-tiny和YOLOv7中的基线模型相比,显著提高了性能。此外,为了解决YOLOv7中CIOU的局限性,我们引入了一种改进的方法ZIOU,该方法已经在海面目标数据集上进行了严格的评估并证明了它的有效性。对比研究表明,yoloo - esfm不仅在参数和FLOPs方面保持了效率,而且在海面目标数据集和PASCAL VOC 07+12数据集上的检测精度都超过了YOLOv7。
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引用次数: 0
Analysis of object detection accuracy based on the density of 3D point clouds for deep learning-based shipyard datasets 基于深度学习船厂数据集三维点云密度的目标检测精度分析
IF 2.3 3区 工程技术 Q2 ENGINEERING, MARINE Pub Date : 2025-01-01 DOI: 10.1016/j.ijnaoe.2025.100648
Ki-Seok Jung , Dong-Kun Lee
3D point clouds are a crucial data format for accurately capturing geometric information in large-scale industrial environments such as shipyards. Deep learning-based object detection technology using 3D point clouds enables automated production management and process optimization. However, the large volume characteristic of 3D point clouds remains a challenge due to the resources and time required for data processing and dataset construction. The large volume of 3D point clouds leads to excessive computational costs, storage demands, and time consumption during dataset construction and training. Therefore, it is necessary to appropriately reduce the dataset size for efficient utilization while ensuring object detection performance. This necessitates a study on dataset downsampling strategies that maintain optimal density and detection accuracy. In this study, an experimental dataset similar to the S3DIS (Stanford Large-Scale 3D Indoor Spaces) dataset was constructed. The density of the 3D point clouds was adjusted in five levels by reducing points per unit area by 20% increments. These datasets were applied to a deep learning architecture to analyze object detection accuracy. Subsequently, the findings were applied to a shipyard dataset to streamline large volume point clouds and evaluate detection performance, thereby assessing their practical applicability. The results demonstrated that reducing the experimental dataset density to approximately 20% still maintained object detection accuracy of around 95% IoU for key objects. This indicates that lightweight datasets can reduce processing resources and costs while preserving detection performance. Additionally, applying the approach to real shipyard datasets revealed that object detection was feasible with reduced data (approximately 4.6% of the raw data). This study provides a practical framework for constructing efficient deep learning models for object detection by downsampling datasets in large-scale industrial environments like shipyards. It is expected to contribute to the establishment of automated data management systems for production management and process efficiency enhancement. Further analysis is required to evaluate performance at extreme low densities (below 20%). Moreover, while this study employed simple downsampling techniques, future work should explore the performance of various downsampling methods to optimize detection accuracy.
三维点云是在造船厂等大型工业环境中准确捕获几何信息的关键数据格式。使用3D点云的基于深度学习的目标检测技术可实现自动化生产管理和流程优化。然而,由于数据处理和数据集构建所需的资源和时间,三维点云的大体积特征仍然是一个挑战。大量的三维点云导致数据集构建和训练过程中计算成本、存储需求和时间消耗过大。因此,在保证目标检测性能的同时,适当减小数据集的大小是很有必要的。这就需要研究保持最佳密度和检测精度的数据集降采样策略。本研究构建了一个类似于S3DIS (Stanford Large-Scale 3D Indoor Spaces)数据集的实验数据集。通过将单位面积上的点减少20%的增量,对三维点云的密度进行了五个级别的调整。这些数据集被应用于一个深度学习架构来分析目标检测的准确性。随后,将研究结果应用于造船厂数据集,以简化大体积点云并评估检测性能,从而评估其实际适用性。结果表明,将实验数据集密度降低到20%左右,对于关键目标仍然保持95% IoU左右的目标检测精度。这表明轻量级数据集可以在保持检测性能的同时减少处理资源和成本。此外,将该方法应用于真实造船厂数据集表明,减少数据(约为原始数据的4.6%)的目标检测是可行的。该研究为构建高效的深度学习模型提供了一个实用框架,该模型通过对造船厂等大型工业环境中的数据集进行下采样来进行目标检测。预期它将有助于建立自动化数据管理系统,以促进生产管理和提高过程效率。需要进一步分析以评估极低密度(低于20%)下的性能。此外,虽然本研究采用了简单的下采样技术,但未来的工作应该探索各种下采样方法的性能,以优化检测精度。
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引用次数: 0
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International Journal of Naval Architecture and Ocean Engineering
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