Marine Structures最新文献_第4页

Structural strength and fatigue analyses of large-scale underwater compressed hydrogen energy storage accumulator 大型水下压缩氢储能蓄能器的结构强度和疲劳分析

IF 4 2区工程技术

Marine Structures Pub Date : 2024-08-30 DOI: 10.1016/j.marstruc.2024.103684

Hu Wang , Zhiwen Wang , David S-K. Ting , Rupp Carriveau , Tonio Sant , Wei Xiong

{"title":"Structural strength and fatigue analyses of large-scale underwater compressed hydrogen energy storage accumulator","authors":"Hu Wang , Zhiwen Wang , David S-K. Ting , Rupp Carriveau , Tonio Sant , Wei Xiong","doi":"10.1016/j.marstruc.2024.103684","DOIUrl":"10.1016/j.marstruc.2024.103684","url":null,"abstract":"<div><p>Underwater compressed hydrogen energy storage (UWCHES) is a potential solution for offshore energy storage. By taking advantage of the hydrostatic pressure of deep seawater, the compressed hydrogen can be isobarically stored in underwater artificial energy storage accumulators. The accumulator should withstand high pressure and large buoyancy and possess reliable anchoring to the seabed. In this study, the structural strength analysis and fatigue life of the large-scale accumulator is conducted employing the finite element method (FEM). The dimensionless stress prediction model and dimensionless fatigue life prediction model are developed through dimensional analysis and multivariate regression analysis. The performance of the accumulator with operating water depth of 100∼300 m, gas storage volume of 1081∼10128 m³, and concrete wall thickness of 0.1∼0.63 m is investigated. The results show that with an operating water depth of 100 m, gas storage capacity of 10,128 m<sup>3</sup>, and concrete wall thickness of 0.63 m, the maximum compressive stress is 1.43 MPa (yield strength is 60 MPa) and the maximum tensile stress of the accumulator is 2.55 MPa (yield strength is 6 MPa). The design fatigue life is 10<sup>6</sup> cycles which is larger than the expected service life of 10<sup>4</sup> cycles. Therefore, the accumulator structure meets the static strength and fatigue life. As the operating water depth increases with a consistent gas storage capacity, a transition in the stress state shifts from primarily tensile stress to predominantly compressive stress. The accuracy of the dimensionless stress prediction model and the dimensionless fatigue life prediction model were verified, with maximum deviations of 10.3 % and 13.7 %, respectively. Furthermore, the anchoring factor of safety of 1.12 is achieved.</p></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"98 ","pages":"Article 103684"},"PeriodicalIF":4.0,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Predicting heave and pitch motions of an FPSO using meta-learning 利用元学习预测浮式生产储油轮的倾斜和俯仰运动

IF 4 2区工程技术

Marine Structures Pub Date : 2024-08-29 DOI: 10.1016/j.marstruc.2024.103681

Yue Liu , Xiantao Zhang , Qing Dong , Xiaoxian Guo , Xinliang Tian , Gang Chen

{"title":"Predicting heave and pitch motions of an FPSO using meta-learning","authors":"Yue Liu , Xiantao Zhang , Qing Dong , Xiaoxian Guo , Xinliang Tian , Gang Chen","doi":"10.1016/j.marstruc.2024.103681","DOIUrl":"10.1016/j.marstruc.2024.103681","url":null,"abstract":"<div><p>Real-time motion prediction is helpful in guaranteeing the operation stability of a Floating Production Storage Offloading (FPSO) unit. Recurrent neural networks (RNNs) are becoming feasible alternatives to numerical simulations for motion prediction as artificial intelligence develops rapidly. In this study, model-agnostic meta-learning (MAML) is combined with RNNs to deterministically predict the heave and pitch motions of a ship-shaped FPSO. This approach is motivated by the fact that MAML improves training efficiency without losing accuracy. The data came from a scaled model test conducted at Shanghai Jiao Tong University’s deepwater wave basin. Before introducing MAML, we verified that long short-term memory (LSTM) and gated recurrent unit (GRU) could accurately predict the heave and pitch of about 7.68 s into the future. With fewer learnable parameters than LSTM, GRU demonstrates slightly better accuracy. Therefore, this study focuses particularly on the combination of GRU and MAML. The parameters of MAML, including order of derivative, step size, number of adaption gradient updates, and batch size of the tasks, are evaluated systemically in terms of accuracy and training efficiency. With the assistance of MAML, GRU’s training efficiency for heave and pitch has significantly improved, increasing by approximately 65% and 55%, respectively. Meanwhile, the prediction error for both has decreased by about 10%. Notably, MAML’s performance is minimally affected by variations in incoming wave direction and sea state, as well as the randomness and temporal variability of the motion. MAML is a powerful tool that enables RNNs to achieve real-time prediction of FPSO motion.</p></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"98 ","pages":"Article 103681"},"PeriodicalIF":4.0,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Insights into the scale effects on ship motions and wave loads considering hydroelasticity 考虑到水弹性，洞察船舶运动和波浪载荷的尺度效应

IF 4 2区工程技术

Marine Structures Pub Date : 2024-08-26 DOI: 10.1016/j.marstruc.2024.103683

Jialong Jiao , Zhenwei Chen , Bowen Ma , Xing Chang

引用次数: 0

Comparative study of numerical modelling and experimental investigation for vessel-docking operations 船舶靠岸作业的数值模拟与实验研究比较

IF 4 2区工程技术

Marine Structures Pub Date : 2024-08-24 DOI: 10.1016/j.marstruc.2024.103680

Xueliang Wen , Jianan Zhang , Muk Chen Ong , Aleksander Kniat

{"title":"Comparative study of numerical modelling and experimental investigation for vessel-docking operations","authors":"Xueliang Wen , Jianan Zhang , Muk Chen Ong , Aleksander Kniat","doi":"10.1016/j.marstruc.2024.103680","DOIUrl":"10.1016/j.marstruc.2024.103680","url":null,"abstract":"<div><p>A comparative study between numerical modelling and experimental investigation is performed to validate the developed numerical method for simulating floating dock operations with a vessel on board. Both model-scale and full-scale experimental tests are performed on floating docks with a vessel on board, and the draughts using draught meters, floating positions and bending of the floating dock are measured. The present numerical method is proposed based on a quasi-static assumption during vessel-docking operations. A static analysis model is built to determine the static response of a floating dock under a specific ballast water distribution based on a hydrostatic force model and a Newton-Raphson method. A bending model is proposed to calculate the deflection of the floating dock along the longitudinal direction. Results of the mode-scale tests show that the draught measurements and the floating positions of the dock and vessel predicted using the present numerical method agree well with the corresponding experimental results. It proves the accuracy of the present numerical method for simulating vessel-docking operations. Moreover, a well-designed ballast plan enables successful de-ballasting operations on the model-scale dock, even in the event of one to three pump failures. The comparison of the deflection changes of the floating dock in the field test measurements further proves the accuracy of the present bending model. Therefore, the validated numerical model tested on both model-scale and full-scale docks provides a reliable foundation for creating digital twin of floating docks in shipyards.</p></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"98 ","pages":"Article 103680"},"PeriodicalIF":4.0,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0951833924001084/pdfft?md5=1934aef515a42ef48875539f46e886af&pid=1-s2.0-S0951833924001084-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142049047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Using the polynomial chaos expansion and bias-variance tradeoff to analyse the statistical characteristics of a trimaran cross-deck structure 利用多项式混沌扩展和偏差-方差权衡分析三体船跨甲板结构的统计特性

IF 4 2区工程技术

Marine Structures Pub Date : 2024-08-24 DOI: 10.1016/j.marstruc.2024.103682

Jun Wang , Jian Wang , Xiaofeng Liang , Yafeng Liu , Xiashuang Wang , Hong Yi

{"title":"Using the polynomial chaos expansion and bias-variance tradeoff to analyse the statistical characteristics of a trimaran cross-deck structure","authors":"Jun Wang , Jian Wang , Xiaofeng Liang , Yafeng Liu , Xiashuang Wang , Hong Yi","doi":"10.1016/j.marstruc.2024.103682","DOIUrl":"10.1016/j.marstruc.2024.103682","url":null,"abstract":"<div><p>The tendency to design high-performance ships demonstrates the importance of the trimaran and the cross-deck is of particular interest due to its exclusive structures and wave loads. Limited by the high cost of structural numerical simulation, relevant studies emphasize the effectiveness of a specific design scheme. This paper introduces the polynomial chaos expansion (PCE) and the bias-variance tradeoff to explore the statistical characteristics of the cross-deck's strength. The geometric model of a high-speed trimaran is built and the load case is designed. Samples are obtained using the Latin hypercube sampling technique and the corresponding stress response of the cross-deck is extracted by the finite element method. To overcome the limitation of sample size, the PCE is applied as a surrogate model to compute the statistical indicators of the stresses and the bias-variance tradeoff is introduced to select the hyperparameter of the PCE. The results show that the stresses at the cross-deck's corner are much higher and more sensitive to the plate thickness than those at other locations. Furthermore, the PCE is also compared with the Monte Carlo simulation to demonstrate its advantages, and it is shown that the PCE performs better under the limitation of sample size considering accuracy and convergence. The feasibility and efficiency of the PCE and bias-variance tradeoff in the statistical analysis of trimaran cross-deck structure is proved. The insights and recommendations summarized will be a useful aid for the design and optimization of the trimaran.</p></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"98 ","pages":"Article 103682"},"PeriodicalIF":4.0,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142049046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanical properties of glass/epoxy composites under artificial seawater environment: Numerical simulation and experimental validation 人工海水环境下玻璃/环氧树脂复合材料的机械性能：数值模拟和实验验证

IF 4 2区工程技术

Marine Structures Pub Date : 2024-07-26 DOI: 10.1016/j.marstruc.2024.103679

Ersan Kirar , Murat Kisa , Mustafa Ozen , Gokhan Demircan , Cenap Guven

{"title":"Mechanical properties of glass/epoxy composites under artificial seawater environment: Numerical simulation and experimental validation","authors":"Ersan Kirar , Murat Kisa , Mustafa Ozen , Gokhan Demircan , Cenap Guven","doi":"10.1016/j.marstruc.2024.103679","DOIUrl":"10.1016/j.marstruc.2024.103679","url":null,"abstract":"<div><p>In ocean engineering applications, glass fiber reinforced composite materials undergo degradation over time due to various aging processes. Accurately assessing the mechanical properties of these materials as they experience aging conditions in marine environment becomes a crucial factor. Although various approaches, such as experimental, theoretical, or finite element methods (FEM), have been employed to investigate the impact of aging processes on composite materials, limited attention has been given to examining the damage of composite plates under the exposure of artificial seawater environments using the MAT162 material model. The objective of this study is to outline a methodology for identifying a group of MAT162 parameters in LS-DYNA through a unit single element analysis. S2 glass/epoxy composites were produced by vacuum assisted resin infusion method. Aging was carried out in artificial seawater environment for 4, 8 and 12 months. Tensile, through thickness tensile, compression, through thickness compression tests were performed and then the finite element modeling was conducted. Maximum strength (X<sub>1T</sub>, X<sub>1C</sub>, X<sub>3T</sub> and S<sub>FC</sub>), element eroding axial strain (E_LIMT), modulus of elasticity (E<sub>1</sub> = E<sub>2</sub>, E<sub>3</sub>), scale factor for residual compressive strength (SFFC), coefficient for strain softening property (AM) parameters were analyzed. It was determined that the proposed model for aging was in good agreement with the experimental study.</p></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"98 ","pages":"Article 103679"},"PeriodicalIF":4.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141954444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Collar plate effect on local joint flexibility of tubular K-joints under IPB moments: Parametric study and predictive equations 领板对 IPB 力矩下管状 K 型关节局部柔韧性的影响：参数研究和预测方程

IF 4 2区工程技术

Marine Structures Pub Date : 2024-07-25 DOI: 10.1016/j.marstruc.2024.103676

Hossein Nassiraei, Hamid Reza Chavoshi

{"title":"Collar plate effect on local joint flexibility of tubular K-joints under IPB moments: Parametric study and predictive equations","authors":"Hossein Nassiraei, Hamid Reza Chavoshi","doi":"10.1016/j.marstruc.2024.103676","DOIUrl":"10.1016/j.marstruc.2024.103676","url":null,"abstract":"<div><p>This study delves into the Local Joint Flexibility (LJF) of tubular K-joints reinforced with the collar plates under in-plane bending moments (IPBMs). 348 reinforced K-joints were simulated to analyze the impacts of the loading conditions (balanced and unbalanced moments), collar plate size (like the length and thickness) alongside the joints’ parameters (<em>θ</em>, <em>γ</em>, <em>β</em>, <em>ξ</em>) on the <em>f</em><sub>LJF</sub> and its proportionality (<em>ψ</em>). The research outcomes demonstrate that factors such as <em>η</em>, <em>λ</em>, and <em>β</em> play a significant role in determining <em>ψ</em>, whereas the influence of <em>ξ</em>, and <em>γ</em> on <em>ψ</em> appears to be negligible. Also, in the reinforced joints, the <em>f</em><sub>LJF</sub> is decreased by 77.4 % compared to the equivalent un-reinforced joint. While the role of the collar plate on the <em>f</em><sub>LJF</sub> is remarkable, the matter had not been investigated on K-joints. Therefore, following the detailed parametric study, two novel equations are proposed to safety estimate the <em>f</em><sub>LJF</sub> for such scenarios.</p></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"98 ","pages":"Article 103676"},"PeriodicalIF":4.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141952275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hydroelastic modelling of a deformable wave energy converter including power take-off 可变形波浪能转换器（包括功率输出）的水弹性建模

IF 4 2区工程技术

Marine Structures Pub Date : 2024-07-23 DOI: 10.1016/j.marstruc.2024.103678

Chao Wang , Yujia Wei , Wenchuang Chen , Luofeng Huang

{"title":"Hydroelastic modelling of a deformable wave energy converter including power take-off","authors":"Chao Wang , Yujia Wei , Wenchuang Chen , Luofeng Huang","doi":"10.1016/j.marstruc.2024.103678","DOIUrl":"10.1016/j.marstruc.2024.103678","url":null,"abstract":"<div><p>Given the advantages of flexible wave energy converters (FlexWECs), such as deformation-led energy harnessing and structural loading compliance, there has been a significant interest in FlexWECs in both academia and industries. To simulate the FlexWEC interaction with ocean surface waves, a 3D computational fluid-structure interaction approach is developed in this study. The fluid and solid governing equations are discretized using finite difference and finite element methods, respectively. An immersed boundary method is used to couple the two independent grid systems. A novel numerical technique is introduced to model the dielectric elastomer generator (DEG) as the power take-off (PTO). The wave energy capture performance is analysed for different PTO configurations and at various wave conditions. Based on the obtained results, the PTO damping coefficient and the relative wavelength range that maximizes the capture width ratio (CWR) are determined. The wavefield results also reveal the presence of wave-height enhancement and attenuation points around a single FlexWEC, providing potential site selection references when deploying multiple FlexWECs in an array.</p></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"98 ","pages":"Article 103678"},"PeriodicalIF":4.0,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0951833924001060/pdfft?md5=50725b11ac87534da0f77335bbc638d6&pid=1-s2.0-S0951833924001060-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141959497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A modified p-y curve model for offshore piles near sandy slopes considering the soil-pile-slope deformation mechanism 考虑土壤-桩-斜坡变形机理的砂质斜坡附近近海桩的修正 p-y 曲线模型

IF 4 2区工程技术

Marine Structures Pub Date : 2024-07-16 DOI: 10.1016/j.marstruc.2024.103675

Pan Liu, Chong Jiang

{"title":"A modified p-y curve model for offshore piles near sandy slopes considering the soil-pile-slope deformation mechanism","authors":"Pan Liu, Chong Jiang","doi":"10.1016/j.marstruc.2024.103675","DOIUrl":"10.1016/j.marstruc.2024.103675","url":null,"abstract":"<div><p>To extend the hyperbolic p-y curve model for level ground to the design of offshore piles near sandy slopes, three modifications must be incorporated: the curve framework, the ultimate soil resistance, and the initial stiffness. A new curve framework is developed, in which the displacement that determines the soil resistance is changed to the sum of the soil compression instead of the pile deflection, by considering the soil-pile-slope deformation mechanism. The ultimate soil resistance, affected by the slope angle and near-slope distance, is derived using the failure wedge (FW) model. A modified initial stiffness is obtained by considering the reduction in effective overburden pressure. The accuracy of the modified model is verified through centrifuge tests and model tests. Finally, the effects of the slope angle, near-slope distance, and soil-pile-slope deformation mechanism on the pile response and the modified model are discussed. The modified model provides practicing engineers with a simple yet comprehensive theoretical approach, without the need for additional pile tests or numerical analysis.</p></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"98 ","pages":"Article 103675"},"PeriodicalIF":4.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An analytical solution for vertical seismic response of an end-bearing pile in saturated soil considering pile-soil and free and scattered field water-soil interaction 饱和土中端承桩垂直地震响应的解析解，考虑桩-土以及自由和散射场水-土相互作用

IF 4 2区工程技术

Marine Structures Pub Date : 2024-07-16 DOI: 10.1016/j.marstruc.2024.103677

Piguang Wang , Baoxin Wang , Zhenhua Dong , Xinglei Cheng , Xiuli Du

{"title":"An analytical solution for vertical seismic response of an end-bearing pile in saturated soil considering pile-soil and free and scattered field water-soil interaction","authors":"Piguang Wang , Baoxin Wang , Zhenhua Dong , Xinglei Cheng , Xiuli Du","doi":"10.1016/j.marstruc.2024.103677","DOIUrl":"10.1016/j.marstruc.2024.103677","url":null,"abstract":"<div><p>A mathematical model is proposed to investigate the dynamic behavior of an end-bearing pile under vertical seismic loading in a water-pile-saturated soil system. The model is based on the Euler-Bernoulli beam theory and takes into account the stress balance between pile sections, representing the pile as a one-dimensional rod. The overall response of site is divided into two components: the free-field response and the scattered-field response. The pile and soil are considered as linearly viscoelastic materials with hysteresis-based damping, while water is modeled as a linear acoustic medium. By accounting for boundary conditions involving force equilibrium and displacement continuity at the pile-soil and water-soil interfaces, an analytical solution for the system response is derived. Analytical expressions of pore water pressure and displacements are obtained, on the basis of considering water-soil interaction in both fields. A parameterization study is then conducted to evaluate the impact of key parameters on the vibration characteristics of piles in a water-pile-saturated soil system.</p></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"98 ","pages":"Article 103677"},"PeriodicalIF":4.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0