Pub Date : 2024-10-14DOI: 10.1016/j.apor.2024.104220
In this paper, we simulate a solitary wave interaction with a variable slope with reflection on a vertical wall by integrating the fully nonlinear Serre–Green–Naghdi (SGN) equations. To this end, we first provide an iterative solution process for the SGN equations so that we can simulate a solitary wave propagating over variable bathymetry. For the purpose of the study, we examine two physical problems. The first is of a solitary wave interaction with a constant slope with reflection on a vertical wall. The simulated solutions are in good agreement with other numerical and experimental data, confirming the validity of the current work. The second is concerned with a perturbation of the first problem, where the constant slope of the first problem is varied; i.e., a variable slope is taken into account. We compare the simulated solutions of the two problems and observe the (physically realistic) effect of the variable slope on shoaling and reflection by the vertical wall.
{"title":"A non-local formulation for simulating the fully nonlinear Serre–Green–Naghdi equations for a solitary wave interaction with a variable slope","authors":"","doi":"10.1016/j.apor.2024.104220","DOIUrl":"10.1016/j.apor.2024.104220","url":null,"abstract":"<div><div>In this paper, we simulate a solitary wave interaction with a variable slope with reflection on a vertical wall by integrating the <em>fully</em> nonlinear Serre–Green–Naghdi (SGN) equations. To this end, we first provide an iterative solution process for the SGN equations so that we can simulate a solitary wave propagating over variable bathymetry. For the purpose of the study, we examine two physical problems. The first is of a solitary wave interaction with a <em>constant</em> slope with reflection on a vertical wall. The simulated solutions are in good agreement with other numerical and experimental data, confirming the validity of the current work. The second is concerned with a perturbation of the first problem, where the constant slope of the first problem is varied; i.e., a variable slope is taken into account. We compare the simulated solutions of the two problems and observe the (physically realistic) effect of the variable slope on shoaling and reflection by the vertical wall.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432347","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}
Pub Date : 2024-10-13DOI: 10.1016/j.apor.2024.104265
Accurate evaluation of cumulative strains in marine soils under long-term cyclic loading is essential for the design and safe operation of offshore wind turbines. This study proposes an enhanced machine learning model to predict the cumulative strain in marine soils subjected to cyclic loading. Cumulative strains of marine soils from five offshore wind farms under long-term cyclic loading were tested. Four prediction models for cumulative strains were developed and evaluated based on test results using the Back Propagation Neural Network (BP-NN), Random Forest (RF), Support Vector Regression (SVR), and eXtreme Gradient Boosting (XGBoost) models, each combined with the Particle Swarm Optimization (PSO) algorithm. The prediction model with the highest accuracy was further analyzed using the SHapley Additive exPlanations (SHAP) method. Results show that the RF and XGBoost algorithms have higher prediction accuracy, with R² values above 0.99, compared to the BP-NN and SVR models. Furthermore, dynamic triaxial test parameters significantly influence the cumulative strain predictions more than the soil properties. This study provides a more efficient method for cumulative strain assessment of marine soils under long-term cyclic loading.
{"title":"Cumulative strain intelligent evaluation of marine soil from offshore wind farms based on enhanced machine learning","authors":"","doi":"10.1016/j.apor.2024.104265","DOIUrl":"10.1016/j.apor.2024.104265","url":null,"abstract":"<div><div>Accurate evaluation of cumulative strains in marine soils under long-term cyclic loading is essential for the design and safe operation of offshore wind turbines. This study proposes an enhanced machine learning model to predict the cumulative strain in marine soils subjected to cyclic loading. Cumulative strains of marine soils from five offshore wind farms under long-term cyclic loading were tested. Four prediction models for cumulative strains were developed and evaluated based on test results using the Back Propagation Neural Network (BP-NN), Random Forest (RF), Support Vector Regression (SVR), and eXtreme Gradient Boosting (XGBoost) models, each combined with the Particle Swarm Optimization (PSO) algorithm. The prediction model with the highest accuracy was further analyzed using the SHapley Additive exPlanations (SHAP) method. Results show that the RF and XGBoost algorithms have higher prediction accuracy, with R² values above 0.99, compared to the BP-NN and SVR models. Furthermore, dynamic triaxial test parameters significantly influence the cumulative strain predictions more than the soil properties. This study provides a more efficient method for cumulative strain assessment of marine soils under long-term cyclic loading.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432348","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}
Pub Date : 2024-10-11DOI: 10.1016/j.apor.2024.104259
The use of underwater explosion bubbles for ice breaking represents an efficient technological advance that is critical for polar exploration. In this paper, we propose an effective numerical methodology for investigating this pertinent issue. By combining the advantages of peridynamics and the Eulerian finite element method, we establish a coupled model for investigating the integral ice-breaking characteristics of underwater explosion bubbles. Our model is capable of accurately simulating the formation of bifurcated ice cracks and capturing the evolution patterns of both ice cracks and crushed ice under various complex working conditions. When the extreme standoff parameter is set to zero, multiple crushed ice formations are effectively generated during contact explosion, and the changes in the height and width of this crushed ice exhibit a predominantly increasing trend over time. Furthermore, our results elucidate the destructive mechanism of the bubble jet on the ice structure. We find that when the initial bubble does not have a strong destructive effect, the jet’s impact becomes more pronounced. The conclusions from this study offer valuable technical support for real-world polar exploration problems.
{"title":"Research on ice-breaking characteristics of underwater explosion bubbles based on an effective coupled model","authors":"","doi":"10.1016/j.apor.2024.104259","DOIUrl":"10.1016/j.apor.2024.104259","url":null,"abstract":"<div><div>The use of underwater explosion bubbles for ice breaking represents an efficient technological advance that is critical for polar exploration. In this paper, we propose an effective numerical methodology for investigating this pertinent issue. By combining the advantages of peridynamics and the Eulerian finite element method, we establish a coupled model for investigating the integral ice-breaking characteristics of underwater explosion bubbles. Our model is capable of accurately simulating the formation of bifurcated ice cracks and capturing the evolution patterns of both ice cracks and crushed ice under various complex working conditions. When the extreme standoff parameter is set to zero, multiple crushed ice formations are effectively generated during contact explosion, and the changes in the height and width of this crushed ice exhibit a predominantly increasing trend over time. Furthermore, our results elucidate the destructive mechanism of the bubble jet on the ice structure. We find that when the initial bubble does not have a strong destructive effect, the jet’s impact becomes more pronounced. The conclusions from this study offer valuable technical support for real-world polar exploration problems.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424494","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}
Pub Date : 2024-10-11DOI: 10.1016/j.apor.2024.104260
Research on online parameter identification and real-time manoeuvring prediction for a class of water-jet unmanned surface vehicle (USV) is carried out in this paper. Utilizing actual sailing data from a water-jet USV, the weighted multi-innovation prediction error method integrated with dynamic window strategy is proposed to identify the manoeuvring parameters of the USV model online. Subsequently, real-time prediction of the water-jet USV's motion is achieved based on the established time-varying model. The thrust generation of water-jet propulsion system and the effect of rotational current on the USV's motion are analyzed simultaneously, and then a three-degree-of-freedom mathematical model is established for the water-jet USV equipped with two water-jet propulsion systems. Due to the weakening of the correction ability of the prediction error method in the later stage, an adaptive step factor with phase adjustment is designed to improve the response accuracy to the error innovation and maintain the algorithm's correction ability. Since the prediction error method updates the identification value using only a single innovation each time, incorporating multi-innovation theory enhances the utilization of historical data, allowing the algorithm to more accurately reflect the current state or trend. In order to fully consider the differences between data points, an adaptive weighting strategy is developed to assign weights according to the contribution of the data in the innovation window to USV modeling, so as to enhance the tracking performance of the time-varying parameters. Aiming at the outliers in the collected data, a dynamic innovation window strategy is designed, and then the data in this window is filtered by Quartile algorithm and the outliers are detected by local outlier factor, so that the window could contain more effective sailing state information. A large amount of actual test data analysis demonstrates that, the algorithm proposed in this paper could achieve more accurate online identification of water-jet USV model parameters and more precise real-time prediction of USV motion, which would provide strong support for safe navigation and efficient control of USV.
{"title":"Online parameter identification and real-time manoeuvring prediction for a water-jet USV based on weighted multi-innovation prediction error method integrated with dynamic window strategy","authors":"","doi":"10.1016/j.apor.2024.104260","DOIUrl":"10.1016/j.apor.2024.104260","url":null,"abstract":"<div><div>Research on online parameter identification and real-time manoeuvring prediction for a class of water-jet unmanned surface vehicle (USV) is carried out in this paper. Utilizing actual sailing data from a water-jet USV, the weighted multi-innovation prediction error method integrated with dynamic window strategy is proposed to identify the manoeuvring parameters of the USV model online. Subsequently, real-time prediction of the water-jet USV's motion is achieved based on the established time-varying model. The thrust generation of water-jet propulsion system and the effect of rotational current on the USV's motion are analyzed simultaneously, and then a three-degree-of-freedom mathematical model is established for the water-jet USV equipped with two water-jet propulsion systems. Due to the weakening of the correction ability of the prediction error method in the later stage, an adaptive step factor with phase adjustment is designed to improve the response accuracy to the error innovation and maintain the algorithm's correction ability. Since the prediction error method updates the identification value using only a single innovation each time, incorporating multi-innovation theory enhances the utilization of historical data, allowing the algorithm to more accurately reflect the current state or trend. In order to fully consider the differences between data points, an adaptive weighting strategy is developed to assign weights according to the contribution of the data in the innovation window to USV modeling, so as to enhance the tracking performance of the time-varying parameters. Aiming at the outliers in the collected data, a dynamic innovation window strategy is designed, and then the data in this window is filtered by Quartile algorithm and the outliers are detected by local outlier factor, so that the window could contain more effective sailing state information. A large amount of actual test data analysis demonstrates that, the algorithm proposed in this paper could achieve more accurate online identification of water-jet USV model parameters and more precise real-time prediction of USV motion, which would provide strong support for safe navigation and efficient control of USV.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424496","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}
Pub Date : 2024-10-10DOI: 10.1016/j.apor.2024.104256
This study presents the results of the numerical simulation analysis, aiming to investigate the temperature effects on the vertical ultimate bearing capacity of the three types of foundations, namely generic spudcan (SGEN), skirted and pile foundations, at different embedded depth ratios H/D (H/D = 1/3, 2/3, and 1 or H/D = 10/3, 5, and 20/3) and strength reduction coefficients su,T/su0 (su,T/su0 = 0.1, 0.5). The latent heat effects on foundation bearing capacities are studied by small strain finite element analysis (FEA). The findings from this investigation and previous research indicate that the foundations' vertical ultimate bearing capacity decreases with time, while it increases with increasing the foundation's embedment ratio. For the foundations, the strength reduction coefficient plays an important role in the vertical ultimate bearing capacity. Notably, as the strength reduction coefficient decreases from 0.5 to 0.1, the reduction rate of the vertical ultimate bearing capacity increases by ∼ 3 to 6 times accordingly. Consequently, a normalized bearing capacity coefficient model has been proposed to provide an optimization tool for engineering design in permafrost regions.
{"title":"Thermal-mechanical sequence coupling analysis on the ultimate bearing capacity of embedded foundations in polar marine permafrost","authors":"","doi":"10.1016/j.apor.2024.104256","DOIUrl":"10.1016/j.apor.2024.104256","url":null,"abstract":"<div><div>This study presents the results of the numerical simulation analysis, aiming to investigate the temperature effects on the vertical ultimate bearing capacity of the three types of foundations, namely generic spudcan (SGEN), skirted and pile foundations, at different embedded depth ratios <em>H</em>/<em>D</em> (<em>H</em>/<em>D</em> = 1/3, 2/3, and 1 or <em>H</em>/<em>D</em> = 10/3, 5, and 20/3) and strength reduction coefficients <em>s</em><sub>u,</sub><em><sub>T</sub></em>/<em>s</em><sub>u0</sub> (<em>s</em><sub>u,</sub><em><sub>T</sub></em>/<em>s</em><sub>u0</sub> = 0.1, 0.5). The latent heat effects on foundation bearing capacities are studied by small strain finite element analysis (FEA). The findings from this investigation and previous research indicate that the foundations' vertical ultimate bearing capacity decreases with time, while it increases with increasing the foundation's embedment ratio. For the foundations, the strength reduction coefficient plays an important role in the vertical ultimate bearing capacity. Notably, as the strength reduction coefficient decreases from 0.5 to 0.1, the reduction rate of the vertical ultimate bearing capacity increases by ∼ 3 to 6 times accordingly. Consequently, a normalized bearing capacity coefficient model has been proposed to provide an optimization tool for engineering design in permafrost regions.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424492","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}
Pub Date : 2024-10-09DOI: 10.1016/j.apor.2024.104264
Hundreds of millions of tons of dredged sludge are generated by waterway dredging worldwide every year. Traditional disposal of dredged sludge, such as in-situ stockpiling and offshore dumping, cannot avoid the waste of land resource and the pollution to marine environment. Sludge stabilization/solidification treatment currently used can achieve the reuse of drudged sludge but requires large investment and time. Therefore, how to turn waste into treasure in an effective, environmentally friendly and cheap way is a notable problem. In this study, the variation of strength of solidified sludge cured in air with water-cement ratio, water content and curing time by unconfined compression test was investigated, and the inner mechanism of strength influenced by water-cement ratio and water content was revealed by XRD test, which offered an optimal working condition. Also, solidified sludge with the maximum strength in the optimal working condition was immersed into seawater at different times, which showed the 7d strength after mixing completion for 8 h immersed into seawater could reach 20.60 MPa (1.37 times of the strength in air), and the prediction formulas considering all the parameters mentioned above were established. At last, a field test of solidified dredged sludge for protection of submarine pipelines was carried out in Bohai Bay, China, which demonstrated the feasibility of mixing dredged sludge with cement on board and solidifying in seawater environment. Compared to the traditional subsea pipeline protection solutions, the cost of using solidified sludge to protect subsea pipelines is 25 % and 39 % less than the cost of using sandbags and concrete mats, respectively. This study provides a more economic and environmentally friendly idea for dredged sludge treatment and subsea pipeline protection than the conventional methods, which provides a new source of green ocean building materials, reduces the pollution of the marine environment by the discharge of dredged sludge, turns waste into treasure and has wide applications in ocean engineering.
{"title":"The properties of cement stabilized dredged sludge solidifying in seawater and its application in the protection of subsea pipelines","authors":"","doi":"10.1016/j.apor.2024.104264","DOIUrl":"10.1016/j.apor.2024.104264","url":null,"abstract":"<div><div>Hundreds of millions of tons of dredged sludge are generated by waterway dredging worldwide every year. Traditional disposal of dredged sludge, such as in-situ stockpiling and offshore dumping, cannot avoid the waste of land resource and the pollution to marine environment. Sludge stabilization/solidification treatment currently used can achieve the reuse of drudged sludge but requires large investment and time. Therefore, how to turn waste into treasure in an effective, environmentally friendly and cheap way is a notable problem. In this study, the variation of strength of solidified sludge cured in air with water-cement ratio, water content and curing time by unconfined compression test was investigated, and the inner mechanism of strength influenced by water-cement ratio and water content was revealed by XRD test, which offered an optimal working condition. Also, solidified sludge with the maximum strength in the optimal working condition was immersed into seawater at different times, which showed the 7d strength after mixing completion for 8 h immersed into seawater could reach 20.60 MPa (1.37 times of the strength in air), and the prediction formulas considering all the parameters mentioned above were established. At last, a field test of solidified dredged sludge for protection of submarine pipelines was carried out in Bohai Bay, China, which demonstrated the feasibility of mixing dredged sludge with cement on board and solidifying in seawater environment. Compared to the traditional subsea pipeline protection solutions, the cost of using solidified sludge to protect subsea pipelines is 25 % and 39 % less than the cost of using sandbags and concrete mats, respectively. This study provides a more economic and environmentally friendly idea for dredged sludge treatment and subsea pipeline protection than the conventional methods, which provides a new source of green ocean building materials, reduces the pollution of the marine environment by the discharge of dredged sludge, turns waste into treasure and has wide applications in ocean engineering.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424495","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}
Pub Date : 2024-10-09DOI: 10.1016/j.apor.2024.104262
Enhancing the understanding of how fiber-reinforced polymer composites respond to high-speed impacts is crucial, particularly in comparison to Quasi-Static Punch Shear Test (QS-PST). While researchers have extensively investigated QS-PST in FRP composites through experimental and numerical approaches, there's a notable gap in studies addressing the aging effects through both experimental and numerical methods. In this study, the QS-PST was conducted on S2 glass fiber reinforced epoxy composite materials aged in an artificial seawater environment. Composite plates were fabricated using Vacuum-assisted resin transfer molding (VARTM). Test samples were subjected to aging for durations of 4, 8, and 12 months. Experimental QS-PST were performed on the samples, followed by Finite Element Analysis (FEA) using LS-DYNA and the MAT 162 material model. The mechanical properties of the composite material were incorporated into the FEA and aging effects were simulated with a maximum error of 8.08% by using the proposed material model. The results indicated that the aging process led to a reduction in the punch shear strength of the composite by up to 26.84%. These findings provide valuable insights into the degradation mechanisms of composite materials in marine environments, aiding in the development of strategies for enhanced durability and performance in such conditions.
{"title":"Quasi-static punch shear behavior of glass/epoxy composite: Experimental and numerical study in artificial seawater environment","authors":"","doi":"10.1016/j.apor.2024.104262","DOIUrl":"10.1016/j.apor.2024.104262","url":null,"abstract":"<div><div>Enhancing the understanding of how fiber-reinforced polymer composites respond to high-speed impacts is crucial, particularly in comparison to Quasi-Static Punch Shear Test (QS-PST). While researchers have extensively investigated QS-PST in FRP composites through experimental and numerical approaches, there's a notable gap in studies addressing the aging effects through both experimental and numerical methods. In this study, the QS-PST was conducted on S2 glass fiber reinforced epoxy composite materials aged in an artificial seawater environment. Composite plates were fabricated using Vacuum-assisted resin transfer molding (VARTM). Test samples were subjected to aging for durations of 4, 8, and 12 months. Experimental QS-PST were performed on the samples, followed by Finite Element Analysis (FEA) using LS-DYNA and the MAT 162 material model. The mechanical properties of the composite material were incorporated into the FEA and aging effects were simulated with a maximum error of 8.08% by using the proposed material model. The results indicated that the aging process led to a reduction in the punch shear strength of the composite by up to 26.84%. These findings provide valuable insights into the degradation mechanisms of composite materials in marine environments, aiding in the development of strategies for enhanced durability and performance in such conditions.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424497","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}
Pub Date : 2024-10-09DOI: 10.1016/j.apor.2024.104252
This paper presents a comprehensive evaluation on the applicability of similitude laws for scaled model design in underwater shaking table (UST) model tests. Scaled models of a sea-crossing bridge pier were first designed in this study, considering five similitude laws and adopting different values of key scale factors for each similitude law. Following this, an extensive numerical database of both prototype and scaled model responses was generated based on validated numerical models, considering structures under pure earthquake (E), earthquakes in still water (ES) as well as coupled earthquake and wave-current actions (EWC). The obtained numerical results were first utilized to investigate the influence of key scale factors on predicted responses. It has been found that density and acceleration distortion lead to underestimation of predicted responses, while geometry distortion results in amplifying predictions. Furthermore, the applicability of similitude laws for designing scaled models was evaluated underpinned by the numerical database. The evaluation results provided suggestions for the proper design of scaled models under different loading conditions, regarding the selection and implementation of similitude laws.
{"title":"Evaluation on the applicability of similitude laws for scaled model design in underwater shaking table tests in the elastic stage","authors":"","doi":"10.1016/j.apor.2024.104252","DOIUrl":"10.1016/j.apor.2024.104252","url":null,"abstract":"<div><div>This paper presents a comprehensive evaluation on the applicability of similitude laws for scaled model design in underwater shaking table (UST) model tests. Scaled models of a sea-crossing bridge pier were first designed in this study, considering five similitude laws and adopting different values of key scale factors for each similitude law. Following this, an extensive numerical database of both prototype and scaled model responses was generated based on validated numerical models, considering structures under pure earthquake (E), earthquakes in still water (ES) as well as coupled earthquake and wave-current actions (EWC). The obtained numerical results were first utilized to investigate the influence of key scale factors on predicted responses. It has been found that density and acceleration distortion lead to underestimation of predicted responses, while geometry distortion results in amplifying predictions. Furthermore, the applicability of similitude laws for designing scaled models was evaluated underpinned by the numerical database. The evaluation results provided suggestions for the proper design of scaled models under different loading conditions, regarding the selection and implementation of similitude laws.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423891","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}
Pub Date : 2024-10-09DOI: 10.1016/j.apor.2024.104258
Submarine pipelines are laid with elastic bending to adapt to the changes in seabed elevation, which usually results in the pipeline being in a pre-stressed state. When replacing and repairing those damaged pipelines, it is easy to encounter rebound and misalignment after pipeline cutting. Therefore, the alignment of the dislocated pipelines must be carried out before replacing and connecting the pipes. At present, some internationally advanced underwater rapid repair equipment only has the function of pipeline lifting, and cannot achieve precise alignment of dislocated pipelines on both sides. It lacks the alignment control model. This article focuses on the alignment problem of dislocated underwater pipelines during replacement and repair. Firstly, based on the Winkler elastic foundation beam and cantilever beam theory, a mechanical model for the alignment of dislocated pipelines is established. Then, an alignment control method is developed based on the mechanical model, and recommended the model's applicability conditions, design parameters, and safe usage range. Finally, the accuracy and reliability of both the alignment mechanics model and control method have been fully verified through numerical method. The established mechanical model and control method in this paper address the crucial issue of aligning misaligned underwater pipelines during repair, providing technical support for engineering applications. And they can be used to guide the design of aligning functional structure for underwater rapid maintenance equipment and also be applied in development of specific alignment schemes for pipeline misalignment scenarios.
{"title":"Research on mechanical model for aligning dislocated underwater pipelines during replacement and repair","authors":"","doi":"10.1016/j.apor.2024.104258","DOIUrl":"10.1016/j.apor.2024.104258","url":null,"abstract":"<div><div>Submarine pipelines are laid with elastic bending to adapt to the changes in seabed elevation, which usually results in the pipeline being in a pre-stressed state. When replacing and repairing those damaged pipelines, it is easy to encounter rebound and misalignment after pipeline cutting. Therefore, the alignment of the dislocated pipelines must be carried out before replacing and connecting the pipes. At present, some internationally advanced underwater rapid repair equipment only has the function of pipeline lifting, and cannot achieve precise alignment of dislocated pipelines on both sides. It lacks the alignment control model. This article focuses on the alignment problem of dislocated underwater pipelines during replacement and repair. Firstly, based on the Winkler elastic foundation beam and cantilever beam theory, a mechanical model for the alignment of dislocated pipelines is established. Then, an alignment control method is developed based on the mechanical model, and recommended the model's applicability conditions, design parameters, and safe usage range. Finally, the accuracy and reliability of both the alignment mechanics model and control method have been fully verified through numerical method. The established mechanical model and control method in this paper address the crucial issue of aligning misaligned underwater pipelines during repair, providing technical support for engineering applications. And they can be used to guide the design of aligning functional structure for underwater rapid maintenance equipment and also be applied in development of specific alignment schemes for pipeline misalignment scenarios.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424493","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}
Pub Date : 2024-10-08DOI: 10.1016/j.apor.2024.104261
An innovative approach that integrates the floating breakwater (FB) with an offshore aquaculture tank is proposed to enhance economic benefits and hydrodynamic properties. To study the hydrodynamics of the integrated structure, a time-synchronized spatial-separated strategy is proposed and applied to the computational fluid dynamics (CFD) to facilitate the complex coupling between waves, mooring force, sloshing flow with the perforated baffle, and body motion. The mooring constraint was achieved by incorporating the catenary mooring theory, as well as employing the volume-averaged porous theory to simulate the perforated baffle effect to provide a low-energy environment required by aquaculture. Corresponding experimental tests were conducted to validate the reliability of the numerical model. The motion response, transmission and reflection coefficients, and sloshing behavior are analyzed to evaluate the hydrodynamics of the integrated structure. Besides, an index referred to as area-weighted-average velocity is introduced to further quantify the kinetic energy of sloshing flow. Results reveal the proposed aquaculture tank-type floating breakwater (AFB) can serve well as tuned liquid dampers (TLDs) to reduce the roll motion, and greatly improve the wave-attenuating capacity. Furthermore, the perforated baffles effectively weaken the sloshing energy at medium and finite filling depths, which are commonly operating depths for aquaculture in a floating closed containment system (FCCS). Overall, the floating breakwater integrated with the aquaculture tank is feasible due to a series of advantages.
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