Journal of Ocean Engineering and Science最新文献

英文中文

Experimental study on the influence of cutting parameters on cutting characteristics of deep-sea seafloor massive sulfide 切削参数对深海海底块状硫化物切削特性影响的实验研究

IF 11.8 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-11-09 DOI: 10.1016/j.joes.2024.10.001

Bei Zhang , Haining Lu , Zhongqin Lin , Shihang Liu , Liwen Deng

The research of seafloor massive sulfide cutting characteristics is in the initial stage, and experimental methods are rarely used to conduct research. In addition, the mechanism of cutting parameters influencing cutting characteristics is not clear. In order to clarify the influence mechanism, the influences of cutting depth and cutting velocity on cutting characteristics are studied experimentally. It is found that with the increase of cutting depth, the load fluctuation is more severe, the breaking yield is increased, the size of the chip is increased, the powdered percentage is decreased, and the externally expanded breaking zone of rock is wider. However, the cutting depth has little effect on the cutting angle, and the breaking angle is between 48° and 61° With the increase in cutting velocity, the number of load fluctuations per unit of time increases significantly, and the size of the chip decreases. However, the breaking yield, powdered percentage, breaking angle and external expansion area remain basically unchanged. The research is of guiding significance to the optimization of the mining head structure and the selection of cutting parameters.

海底块状硫化物切削特性的研究尚处于起步阶段，很少采用实验方法进行研究。此外，切削参数影响切削特性的机理尚不清楚。为了阐明其影响机理，实验研究了切削深度和切削速度对切削特性的影响。研究发现，随着切削深度的增加，载荷波动更剧烈，破碎屈服增大，切屑尺寸增大，粉末状比例减小，岩石外部扩展破碎区变宽。而切削深度对切削角影响不大，断裂角在48°~ 61°之间，随着切削速度的增加，单位时间内载荷波动次数显著增加，切屑尺寸减小。破碎率、粉末率、破碎角、外膨胀面积基本不变。研究结果对矿头结构的优化和切削参数的选择具有指导意义。

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引用次数: 0

ADRC-Based cooperative control for unmanned towing operation by multiple DP tugboats: A comparative study of two cooperative controllers 基于adrc的多艘DP拖船无人拖航协同控制：两种协同控制器的比较研究

IF 11.8 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-10-18 DOI: 10.1016/j.joes.2024.09.004

Xu Jiang , Lei Wang , Yiting Wang

This paper addresses the challenge of coordinated manipulation of an unactuated floating object by multiple tugboats to execute both positioning and towing operation within complex marine environments. We proposes a multi-layer cooperative control algorithm for the multi-tugboat system, including tugboat control level and cooperative control level. At the individual tugboat control level, the dynamic positioning system (DPS) has been enhanced to match the operational behavior of the tugboat, enabling it to handle cable tension and environmental disturbances during transit. The controller incorporates a simple yet effective linear active disturbance rejection control method (ADRC) to counter external disturbances and ensure accurate trajectory tracking without relying on preset models. Moving to the multi-tugboat collaboration level, two distinct control strategies are proposed for towing operations: formation-based (FB) and force-allocation-based (FAB). The FB strategy involves multiple tugboats forming a coordinated formation, with control focused on the formation center to indirectly manipulate the object. On the other hand, the FAB strategy utilizes model predictive control (MPC) for the object to allocate the necessary towing force for each cable, thereby determining the required actions for each tugboat based on the cable model and the needed towing force. Simulation results demonstrate that both control strategies can effectively maneuver the floating object with high accuracy to perform positioning and towing tasks. Nevertheless, due to the variations in their fundamental mechanisms, there are significant discrepancies in towline tension, tugboat utilization, and energy consumption.

本文解决了多艘拖船在复杂海洋环境中协调操纵非驱动漂浮物以执行定位和拖曳操作的挑战。针对多拖船系统，提出了一种多层协同控制算法，包括拖船控制层和协同控制层。在单个拖船控制层面，动态定位系统（DPS）得到了增强，以匹配拖船的操作行为，使其能够处理运输过程中的电缆张力和环境干扰。该控制器采用一种简单而有效的线性自抗扰控制方法（ADRC）来对抗外部干扰，并确保精确的轨迹跟踪，而不依赖于预设模型。在多拖船协作层面，提出了两种不同的拖曳控制策略：基于编队（FB）和基于力分配（FAB）。FB策略涉及多个拖船组成一个协调的编队，控制集中在编队中心，间接操纵目标。另一方面，FAB策略利用对象的模型预测控制（MPC）来分配每条电缆所需的拖曳力，从而根据电缆模型和所需的拖曳力确定每艘拖船所需的动作。仿真结果表明，这两种控制策略都能有效、高精度地操纵漂浮物完成定位和拖曳任务。然而，由于其基本机制的差异，在拖缆张力、拖船利用率和能源消耗方面存在显著差异。

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引用次数: 0

Developing a virtual physical system for vortex-induced vibration studies of a bluff body 研究钝体涡激振动的虚拟物理系统

IF 11.8 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-10-17 DOI: 10.1016/j.joes.2024.09.003

Haojie Ren , Shixiao Fu , Mengmeng Zhang , Yuwang Xu , Hao Ren

A virtual physical system (VPS) for VIV studies of a bluff body is developed to replace the actual physical systems. It can arbitrarily and accurately control and edit the physical parameters, including mass, damping ratio and spring stiffness, specifically for the mass-spring-damper system. The recursive Duhamel integral method (DIM) with unconditional stability was used for the VPS control system, addressing real-time noise filtering problem and simplifying the system as a single input and single output (SISO) one. Delay compensation and inertial force elimination methods were investigated and proposed to overcome the crucial unwanted damping effects. An experimental facility for VIV model tests by VPS was manufactured, and the bluff body model with a measurement system was specially designed to accurately sense the hydrodynamic force during VPS operation. Systematic verification experiments for parameter editing and control of an actual physical target system were conducted, showing that the VPS can reproduce the equivalent spring-damper-mass system in high fidelity with an accuracy error of less than 5 %. VIV model tests for a bluff body at Reynolds numbers (Re= UD/υ, where U is the flow velocity, D represents the diameter of cylinder model, and υ is the kinematic viscosity coefficient) of 5.7E4 and 2.3E5 were performed using the VPS experimental facility, presenting well-Repeated VIV responses at low Re and unexpected VIV response with a large amplitude of 2.4 D at high Re, which can cause severe fatigue damage for relevant structures. The present VPS will provide promising and powerful experimental tools for VIV studies of a bluff body to reveal the related sensitive parameter effects.

为了取代实际的物理系统，开发了一个用于钝体VIV研究的虚拟物理系统（VPS）。它可以任意精确地控制和编辑质量、阻尼比和弹簧刚度等物理参数，特别是针对质量-弹簧-阻尼器系统。将具有无条件稳定性的递归Duhamel积分法（DIM）用于VPS控制系统，解决了实时噪声滤波问题，并将系统简化为单输入单输出（SISO）系统。研究并提出了延迟补偿和惯性力消除方法来克服关键的有害阻尼效应。制作了一套用于VPS进行涡动模型测试的实验装置，并专门设计了带测量系统的钝体模型，以准确地感知VPS运行时的水动力。对实际物理目标系统进行了参数编辑和控制的系统验证实验，结果表明，VPS可以高保真地再现等效弹簧-阻尼器-质量系统，精度误差小于5%。在VPS实验设备上，对雷诺数（Re= UD/υ，其中U为流速，D为圆柱模型直径，υ为运动黏度系数）为5.7E4和2.3E5的钝体进行了涡激振动模型试验，在低Re下表现出良好的重复涡激振动响应，在高Re下表现出幅度达2.4 D的意外涡激振动响应，对相关结构造成严重的疲劳损伤。该VPS将为钝体的涡激振动研究提供强有力的实验工具，以揭示相关的敏感参数效应。

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引用次数: 0

A guidance of solid element application in predicting the ultimate strength of flat plates in compression 实体元在平板极限抗压强度预测中的应用指南

IF 11.8 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-10-15 DOI: 10.1016/j.joes.2024.09.002

Zhuo Wang , Xiangshao Kong , Weiguo Wu , Shen Li , Do Kyun Kim

With the increasing demand in ocean engineering field for the ultimate limit state (ULS) analysis of thick plates, the solid (3D) element has been more frequently used in the ULS analysis. Compared to 2D element, 3D element can better consider the transverse shearing effect during the analysis which usually occurs on thick plates, due to its reliable reflection of geometrical characteristics and kinematic equations of the structures. Besides, 3D element can also facilitate the introduction of influencing factors into the ULS analysis, such as the erosions, cracks and residual stress. This may improve the simulation precision of ULS analysis of thick plate models. Until now, there is a lack of 3D element modelling technique in the ULS analysis of flat/stiffened plates. The present study aims to provide helpful information on 3D elements in the ULS analysis of flat plates under axial compression load. A total of 350 plate scenarios were adopted in the parametric study to consider the effects of 3D element shape (α_yz). It is found that the element shape significantly influences the ULS analysis of flat plates, where planar-like 3D element is not recommended. An empirical formula for determining the optimal 3D element shape of the finite element (FE) model is proposed based on the parametric results. A guidance for implementing the 3D elements is then documented, which may help engineers further understand the ultimate strength characteristic of very thick flat plates.

随着海洋工程领域对厚板极限状态分析的需求日益增加，固体（三维）单元在厚板极限状态分析中得到了越来越多的应用。与二维单元相比，三维单元能够可靠地反映结构的几何特性和运动方程，能够更好地考虑厚板结构在分析过程中经常出现的横向剪切效应。此外，三维单元还可以方便地将侵蚀、裂纹、残余应力等影响因素引入到ULS分析中。这可以提高厚板模型ULS分析的模拟精度。到目前为止，在平面/加筋板的ULS分析中缺乏三维单元建模技术。本研究旨在提供三维单元在轴向压缩载荷下的平板ULS分析中的有用信息。为了考虑三维单元形状（αyz）的影响，在参数化研究中共采用了350种平板场景。发现单元形状对平板的ULS分析有显著影响，不推荐使用平面三维单元。基于参数化计算结果，提出了确定有限元模型三维最优单元形状的经验公式。然后编制了实施3D元件的指南，这可能有助于工程师进一步了解非常厚的平板的极限强度特性。

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引用次数: 0

Numerical simulations of a ship sailing across pack ice area in forward motion under different drafts 船舶在不同气流下向前穿越浮冰区域的数值模拟

IF 11.8 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-09-21 DOI: 10.1016/j.joes.2024.09.001

Ming Zou , Xiang-Jie Tang , Lu Zou , Zao-Jian Zou , Chang-Zhe Chen , Xin-Shu Zhang

Different from the existing CFD-DEM models in which the ship remains stationary, a CFD-DEM model with the ship in forward motion is proposed in this paper to simulate the process of a ship sailing across pack ice area at a forward speed under different drafts. A high-precision method for generating pack ice area on the undisturbed free surface that can be used in conjunction with the proposed model is introduced. Taking an ice-strengthened Panamax bulker as study object, the available model test results are used to verify the reliability of the proposed model, which shows that the model can effectively evaluate the resistance performance and simulate the ship-ice-water interaction. Based on the verified model, the ice resistances on different parts of the hull are first investigated, which reveals that the ice resistance of the bow is most significant, while those of the midship and stern are negligible. Then, the speed dependence of ice resistance under different drafts is studied. It shows a strong nonlinearity under shallow draft, while the nonlinearity gradually weakens as the draft increases. Finally, the proportions of ice resistance and open-water resistance in the total resistance under different drafts and ship speeds are discussed.

不同于现有船舶静止的CFD-DEM模型，本文提出了船舶前进运动的CFD-DEM模型，模拟船舶在不同吃水情况下以前进速度穿越浮冰区的过程。介绍了一种可与所提出的模型结合使用的高精度无扰动自由表面浮冰面积生成方法。以一艘冰强化巴拿马型散货船为研究对象，利用已有的模型试验结果验证了所建模型的可靠性，结果表明所建模型能够有效地评估船舶的阻力性能，并能模拟船舶-冰-水相互作用。在验证模型的基础上，首先对船体不同部位的冰阻进行了研究，结果表明船首部位的冰阻最为显著，而船中部和船尾部位的冰阻可以忽略不计。然后，研究了不同气流下冰阻对速度的依赖关系。浅吃水下非线性较强，随着吃水的增加非线性逐渐减弱。最后讨论了在不同吃水和航速条件下，冰阻和开阔水域阻力占总阻力的比例。

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引用次数: 0

Influence of sample intervals in real-sea trails on the nonparametric model of 3-DoF ship motion predictions 真实海迹样本间隔对三自由度船舶运动预测非参数模型的影响

IF 11.8 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-09-17 DOI: 10.1016/j.joes.2024.08.002

Jiankun Lou , Hongdong Wang , Wenliang Yuan , Hong Yi

The accuracy of ship manoeuvrability models based on real sea trail data heavily relies on data quality, as noise and measurement errors pose significant challenges in data processing and model training. This study employs a deep learning approach for the nonparametric modelling of 3-DoF ship manoeuvrability predictions, utilizing data from zigzag tests conducted at sea. It examines how the limitations of measurement equipment affect data analysis, emphasizing the impact of different sample intervals on model accuracy. Our study further explores the efficacy of deep neural networks in capturing low-frequency components more effectively than high-frequency ones, discussing the data sampling process and frequency analysis in the response domain for training set construction. Simulation results indicate that both excessively small and large sample intervals can significantly compromise predictions of motion, location, and heading angles. Moreover, to enhance the evaluation of the deep learning-based nonparametric model, incorporating a test case with a minimal rudder angle is crucial for assessing the prediction precision. Generally, a sample interval ranging from 0.4 s to 0.6 s is identified as optimal for data down sampling in real sea trails, balancing accuracy and computational efficiency.

基于真实海迹数据的船舶操纵性模型的准确性很大程度上依赖于数据质量，噪声和测量误差给数据处理和模型训练带来了重大挑战。本研究采用深度学习方法对3-DoF船舶机动性预测进行非参数建模，利用海上进行的之字形试验数据。它考察了测量设备的局限性如何影响数据分析，强调了不同样本间隔对模型精度的影响。我们的研究进一步探讨了深度神经网络在捕获低频成分方面比高频成分更有效的功效，讨论了用于训练集构建的响应域的数据采样过程和频率分析。仿真结果表明，过小和过大的样本间隔都会显著影响运动、位置和航向角的预测。此外，为了提高对基于深度学习的非参数模型的评估，结合最小舵角的测试用例对评估预测精度至关重要。一般来说，0.4 s到0.6 s的采样间隔被认为是真实海径数据下行采样的最佳选择，可以平衡精度和计算效率。

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引用次数: 0

Numerical and experimental studies on propulsion performance of a novel tandem paddles propulsor 新型串联式桨叶推进器推进性能的数值与实验研究

IF 13 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-09-07 DOI: 10.1016/j.joes.2024.08.001

Longqing Xin, Peng Liu, Huajun Li, Siqi Wang, Yuhua Lyu, Yaqian Li, Guodong Feng

Normally, small unmanned vessels used to clean floating litter on water adopt a paddle wheel as a propulsor to satisfy its shallow-draft requirements; however, this type of propulsor has bulky structures and inefficient propulsion. In this study, a novel tandem paddles propulsor (TPP) was developed, and its propulsion performance was analyzed and compared with that of a paddle wheel propulsor (PWP). Using the RNG k-ε turbulence model and sliding grid technique, the hydrodynamic performance of the PWP was simulated in computational fluid dynamics (CFD) software to verify the reliability of the numerical method. Subsequently, the propulsion performances of the two types of propulsors were simulated with different immersion depths and advanced coefficients, and the differences in their mechanical characteristics and flow field evolution were discussed and compared. The results indicate that the proposed TPP generates 2.75 times more thrust and 1.99 times greater efficiency than the PWP, exhibiting superior propulsion capability in shallow-draft vessels.

一般情况下，用于清理水上浮物的小型无人船采用桨轮作为推进器，以满足其浅吃水要求；然而，这种推进器结构笨重，推进效率低。研制了一种新型串联桨叶推进器（TPP），对其推进性能进行了分析，并与桨轮推进器（PWP）进行了比较。利用RNG k-ε湍流模型和滑动网格技术，在计算流体动力学（CFD）软件中对压水机的水动力性能进行了模拟，验证了数值方法的可靠性。随后，对两种推进器在不同浸没深度和推进系数下的推进性能进行了仿真，讨论并比较了两种推进器在力学特性和流场演化方面的差异。结果表明，与PWP相比，TPP的推力和效率分别提高了2.75倍和1.99倍，在浅吃水船舶中表现出优越的推进能力。

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引用次数: 0

Run length encoding based weld seam detection from point clouds of ship stiffened panel 基于行程长度编码的船舶加筋板点云焊缝检测

IF 13 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-08-02 DOI: 10.1016/j.joes.2024.07.002

Jun Li , Zhen Chen , Chongben Ni , Puhao Lei

A vision-based weld seam detector is crucial for intelligent welding in ship stiffened panel as it influences the working efficiency of welding robots. This paper introduces an innovative Run Length Encoding (RLE) based Line Segment Detector (RSD) that is capable of extracting line segments from point clouds. The RLE is firstly employed to compress point cloud data by encoding them into runs. Then, the directional feature of significant line segments is determined according to the analysis of level line angles, facilitating a global line segment detection mechanism. This enables RSD to capture more complete line segments compared to region-based detection methods. Notably, this method obviates the need for manual parameter adjustments and does not require any prior information. The effectiveness and superiority of RSD are confirmed by testing various workpieces in a laboratory setting and comparing its performance with other detectors.

基于视觉的焊缝检测仪对船舶加筋板的智能焊接至关重要，它直接影响到焊接机器人的工作效率。本文介绍了一种新颖的基于运行长度编码（RLE）的线段检测器（RSD），该检测器能够从点云中提取线段。首先利用RLE对点云数据进行压缩，将点云数据进行编码。然后，根据水平线角的分析，确定重要线段的方向特征，实现全局线段检测机制；与基于区域的检测方法相比，这使得RSD能够捕获更完整的线段。值得注意的是，这种方法不需要手动调整参数，也不需要任何先验信息。通过在实验室环境中测试各种工件，并将其性能与其他探测器进行比较，证实了RSD的有效性和优越性。

引用次数: 0

On thermoelastic problem based on four theories with the efficiency of the magnetic field and gravity 基于磁场和重力效率四种理论的热弹性问题

IF 13 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-08-01 DOI: 10.1016/j.joes.2022.02.007

The fundamental objective of this paper is to study the effectiveness of magnetic field and gravity on an isotropic homogeneous thermoelastic structure based on four theories of generalized thermoelasticity. In another meaning, the models of coupled dynamic theory (CDT), Lord-Shulman (LS), Green-Lindsay (GL) as well as Green-Naghdi (GN II) will be taken in the consideration. Then, applying the harmonic method (normal mode technique), the solution of the governing equations and the expressions for the components of the displacement, temperature and (Mechanical and Maxwell's) stresses is taken into account and calculated numerically. The impacts of the gravity and magnetic field are illustrated graphically which are pronounced on the different physical quantities. Finally, the results of some research that others have previously obtained may be found some or all of them as special cases from this study.

本文的基本目标是基于四种广义热弹性理论，研究磁场和重力对各向同性均质热弹性结构的影响。换言之，本文将考虑耦合动力学理论（CDT）、Lord-Shulman（LS）、Green-Lindsay（GL）和 Green-Naghdi （GN II）模型。然后，应用谐波法（法向模态技术），考虑并数值计算了位移、温度和（机械应力和麦克斯韦）应力分量的控制方程和表达式的解法。重力场和磁场对不同物理量的影响以图表说明。最后，从本研究中可以找到一些或全部作为特例的其他研究成果。

引用次数: 0

Explicit solutions to the time-fractional generalized dissipative Kawahara equation 时间分数广义耗散Kawahara方程的显式解

IF 13 1区工程技术 Q1 ENGINEERING, MARINE

Journal of Ocean Engineering and Science

Pub Date : 2024-08-01 DOI: 10.1016/j.joes.2022.02.013

In this paper, the generalized dissipative Kawahara equation in the sense of conformable fractional derivative is presented and solved by applying the tanh-coth-expansion and sine-cosine function techniques. The quadratic-case and cubic-case are investigated for the proposed model. Expected solutions are obtained with highlighting to the effect of the presence of the alternative fractional-derivative and the effect of the added dissipation term to the generalized Kawahara equation. Some graphical analysis is presented to support the findings of the paper. Finally, we believe that the obtained results in this work will be important and valuable in nonlinear sciences and ocean engineering.

本文提出了符合分式导数意义上的广义耗散川原方程，并应用 tanh-coth-expansion 和正弦余弦函数技术进行了求解。对所提出模型的二次方和三次方情况进行了研究。得到的预期解突出了替代分式-衍生物存在的影响和广义川原方程添加耗散项的影响。本文还给出了一些图形分析，以支持本文的研究结果。最后，我们相信这项工作所取得的成果将对非线性科学和海洋工程具有重要价值。

引用次数: 0

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