Pub Date : 2024-06-01DOI: 10.17736/ijope.2024.ty15
Shuai Jia, Yanlin Wang, Ziguang Jia, Yetian Li, Xin Su
Aging offshore platforms pose safety risks, with cracks compromising integrity. A novel crack monitoring method using displacement, strain, and a stress intensity factor was proposed. Hybrid fiber sensing on a jacket platform model proved effective for comprehensive offshore crack monitoring. Simulation guided the design of displacement sensors and sensing tapes. Experiments validated the system’s efficacy with a greater than 0.99 linear correlation for optical fiber sensors, a less than 5% average sensitivity error, and a greater than 95% strain transfer rate for tapes. Field tests affirmed high sensitivity and accuracy—vital for offshore platform safety.
{"title":"Experimental Study of Structural Crack Monitoring for Ocean Platform Based on a Hybrid Fiber Sensing Technique","authors":"Shuai Jia, Yanlin Wang, Ziguang Jia, Yetian Li, Xin Su","doi":"10.17736/ijope.2024.ty15","DOIUrl":"https://doi.org/10.17736/ijope.2024.ty15","url":null,"abstract":"Aging offshore platforms pose safety risks, with cracks compromising integrity. A novel crack monitoring method using displacement, strain, and a stress intensity factor was proposed. Hybrid fiber sensing on a jacket platform model proved effective for comprehensive offshore crack monitoring. Simulation guided the design of displacement sensors and sensing tapes. Experiments validated the system’s efficacy with a greater than 0.99 linear correlation for optical fiber sensors, a less than 5% average sensitivity error, and a greater than 95% strain transfer rate for tapes. Field tests affirmed high sensitivity and accuracy—vital for offshore platform safety.","PeriodicalId":503139,"journal":{"name":"International Journal of Offshore and Polar Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141405712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17736/ijope.2023.mt35
Xin Li, Ning Ma, QiQi Shi, X. Gu
The Power-activation Feed-forward Neural Network (PFN) is used to achieve real-time prediction of the ship’s parametric roll motion. The theoretical rationality of real-time prediction based on the ship’s rolling motion time series data is verified. Sequence-to-Sequence models are proposed and used to compare the PFN model, Long Short-Term Memory model, and Convolutional Neural Network. Three different groups of model experiment data are used for comparison. Results show that PFN has advantages in real-time prediction of parametric roll motion due to its time-varying weight adjustment methods, with a more effective mapping mode, higher accuracy, and shorter computing time.
{"title":"Real-time Prediction of Parametric Roll Motion via Power-activation Feed-forward Neural Network with Model Experiment Data","authors":"Xin Li, Ning Ma, QiQi Shi, X. Gu","doi":"10.17736/ijope.2023.mt35","DOIUrl":"https://doi.org/10.17736/ijope.2023.mt35","url":null,"abstract":"The Power-activation Feed-forward Neural Network (PFN) is used to achieve real-time prediction of the ship’s parametric roll motion. The theoretical rationality of real-time prediction based on the ship’s rolling motion time series data is verified. Sequence-to-Sequence models are proposed and used to compare the PFN model, Long Short-Term Memory model, and Convolutional Neural Network. Three different groups of model experiment data are used for comparison. Results show that PFN has advantages in real-time prediction of parametric roll motion due to its time-varying weight adjustment methods, with a more effective mapping mode, higher accuracy, and shorter computing time.","PeriodicalId":503139,"journal":{"name":"International Journal of Offshore and Polar Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141405837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17736/ijope.2024.ts27
P. Zou, N. Ruiter, Jeremy D. Bricker, W. S. Uijttewaal
Marine biofouling is a major concern in the operational performance of submerged floating tunnels (SFTs). The objective of this research is to extend hydrodynamic conditions in experiments and numerically investigate the effects of marine fouling on the hydrodynamic behavior of SFTs, including flow characteristics and forces on the SFT subject to waves. A sensitivity analysis of roughness parameters including different roughness heights and roughness coverage ratios is carried out. Additionally, the hydrodynamic forces of a roughened SFT with a circular shape and a newly designed parametric shape are compared.
{"title":"Numerical Simulation of Hydrodynamic Forces on a Submerged Floating Tunnel with Surface Roughness Subject to Wave Loading","authors":"P. Zou, N. Ruiter, Jeremy D. Bricker, W. S. Uijttewaal","doi":"10.17736/ijope.2024.ts27","DOIUrl":"https://doi.org/10.17736/ijope.2024.ts27","url":null,"abstract":"Marine biofouling is a major concern in the operational performance of submerged floating tunnels (SFTs). The objective of this research is to extend hydrodynamic conditions in experiments and numerically investigate the effects of marine fouling on the hydrodynamic behavior of SFTs, including flow characteristics and forces on the SFT subject to waves. A sensitivity analysis of roughness parameters including different roughness heights and roughness coverage ratios is carried out. Additionally, the hydrodynamic forces of a roughened SFT with a circular shape and a newly designed parametric shape are compared.","PeriodicalId":503139,"journal":{"name":"International Journal of Offshore and Polar Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141406736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.17736/ijope.2024.sv08
Kouki Kawamura, Takanori Hino
To assess the survivability of damaged ships, a numerical method is developed to simulate the motion of a floating body with partially filled tanks. The present method couples the moving particle simulation (MPS) with the finite volume method (FVM) by using peer-to-peer file exchange to retain the advantages of each discretization technique. In this study, the motion of a floating body with partially filled tanks in incident regular waves is analyzed. The MPS is applied for the water in the tanks, and the FVM is applied for the floating body interaction with the waves. Calculated results show good agreement with the data measured, and the relationship between the hydrodynamic forces exerted by the water in the tanks and the wave is revealed.
{"title":"Development of a Coupled Method of Finite Volume and Particle Methods Based on Peer-to-Peer File Exchange","authors":"Kouki Kawamura, Takanori Hino","doi":"10.17736/ijope.2024.sv08","DOIUrl":"https://doi.org/10.17736/ijope.2024.sv08","url":null,"abstract":"To assess the survivability of damaged ships, a numerical method is developed to simulate the motion of a floating body with partially filled tanks. The present method couples the moving particle simulation (MPS) with the finite volume method (FVM) by using peer-to-peer file exchange to retain the advantages of each discretization technique. In this study, the motion of a floating body with partially filled tanks in incident regular waves is analyzed. The MPS is applied for the water in the tanks, and the FVM is applied for the floating body interaction with the waves. Calculated results show good agreement with the data measured, and the relationship between the hydrodynamic forces exerted by the water in the tanks and the wave is revealed.","PeriodicalId":503139,"journal":{"name":"International Journal of Offshore and Polar Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140279929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.17736/ijope.2024.jc922
S. Tödter, J. Neugebauer, O. el Moctar
The assessment of the structural strength of liquefied natural gas membrane tanks onboard ships requires the investigation of the sloshing-induced impact loads. Those loads are usually determined via model tests usually neglecting the influence of swell. In the present study, we experimentally investigated sloshing-induced loads resulting from ship motions in long-and short-crested pure wind seas and combinations of wind sea and swell. Impact loads and counts were correlated with wave spreading functions, tank filling levels, and tank natural sloshing frequencies. Results emphasized that short-crested seas increased impact loads for highly filled tanks. Furthermore, swell had a significant influence on sloshing-induced impact loads.
{"title":"Experimental Investigation of the Influence of Short-Crested Seas and Swell on Sloshing-Induced Impact Loads","authors":"S. Tödter, J. Neugebauer, O. el Moctar","doi":"10.17736/ijope.2024.jc922","DOIUrl":"https://doi.org/10.17736/ijope.2024.jc922","url":null,"abstract":"The assessment of the structural strength of liquefied natural gas membrane tanks onboard ships requires the investigation of the sloshing-induced impact loads. Those loads are usually determined via model tests usually neglecting the influence of swell. In the present study, we experimentally investigated sloshing-induced loads resulting from ship motions in long-and short-crested pure wind seas and combinations of wind sea and swell. Impact loads and counts were correlated with wave spreading functions, tank filling levels, and tank natural sloshing frequencies. Results emphasized that short-crested seas increased impact loads for highly filled tanks. Furthermore, swell had a significant influence on sloshing-induced impact loads.","PeriodicalId":503139,"journal":{"name":"International Journal of Offshore and Polar Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140283159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.17736/ijope.2024.ak59
Shun Xu, Weiwen Zhao, Decheng Wan, Yan Zhao
A coupled large eddy simulation and aero-hydro-moor-servo dynamics code is used to perform numerical simulations of a floating offshore wind turbine (FOWT) under yawed conditions. The atmospheric boundary layer wind field is simulated by large eddy simulation (LES) with sufficient simulation duration as the inflow wind condition. Two cases with 15° and 30° yaw angles of wind turbine are performed, and the results of aerodynamics, hydrodynamics and wake characteristics are compared and analyzed with that of non-yaw scenario. It is concluded that the rotor power of FOWT decreases with increase of yaw angle, whereas the rotor thrust of 15° yaw angle is slightly larger than that of non-yaw situation. There is no distinct difference of platform surge motion and pitch motion between the 15° yaw angle and non-yaw scenario, whereas the two motions of 30° yaw angle are significantly less than that of non-yaw scenario. The platform sway motion increases with the increase of yaw angle due to the crosswise component of rotor thrust of wind turbine. What’s more, faster wake recovery and more significant wake deflection with increase of yaw angle is observed, which is beneficial for the inflow wind condition and power generation of downstream wind turbine.
{"title":"Dynamic Responses and Wake Characteristics of a Floating Offshore Wind Turbine in Yawed Conditions","authors":"Shun Xu, Weiwen Zhao, Decheng Wan, Yan Zhao","doi":"10.17736/ijope.2024.ak59","DOIUrl":"https://doi.org/10.17736/ijope.2024.ak59","url":null,"abstract":"A coupled large eddy simulation and aero-hydro-moor-servo dynamics code is used to perform numerical simulations of a floating offshore wind turbine (FOWT) under yawed conditions. The atmospheric boundary layer wind field is simulated by large eddy simulation (LES) with sufficient simulation duration as the inflow wind condition. Two cases with 15° and 30° yaw angles of wind turbine are performed, and the results of aerodynamics, hydrodynamics and wake characteristics are compared and analyzed with that of non-yaw scenario. It is concluded that the rotor power of FOWT decreases with increase of yaw angle, whereas the rotor thrust of 15° yaw angle is slightly larger than that of non-yaw situation. There is no distinct difference of platform surge motion and pitch motion between the 15° yaw angle and non-yaw scenario, whereas the two motions of 30° yaw angle are significantly less than that of non-yaw scenario. The platform sway motion increases with the increase of yaw angle due to the crosswise component of rotor thrust of wind turbine. What’s more, faster wake recovery and more significant wake deflection with increase of yaw angle is observed, which is beneficial for the inflow wind condition and power generation of downstream wind turbine.","PeriodicalId":503139,"journal":{"name":"International Journal of Offshore and Polar Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140279823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.17736/ijope.2024.su02
Kantaro Suzuki, T. Iida, Hidetsugu Iwashita, M. Minoura
In studies evaluating ship performances running in actual seas, shaft powers, ship motions, strains, and the like are usually used. In addition to obtaining these physical quantities, determining the pressure distribution on hulls would be useful for rational ship design. However, the technique for measuring pressure distribution on a ship’s hull in the actual sea has not been established. Therefore, we propose a method to obtain pressure distribution through the convolution integral by using the pressure measured at only one point. The estimated pressure distribution is validated in comparison with measured experimental values. The estimated pressure is discussed in diffraction and free-motion tests. The effectiveness of the proposed method is further validated by integrating the estimated pressures on the hull surface. Then, the obtained forces or motions estimated from the forces are compared with directly measured values.
{"title":"Prediction of Unsteady Pressure Distribution in Irregular Waves Using Locally Measured Pressure Data and Convolution Integral","authors":"Kantaro Suzuki, T. Iida, Hidetsugu Iwashita, M. Minoura","doi":"10.17736/ijope.2024.su02","DOIUrl":"https://doi.org/10.17736/ijope.2024.su02","url":null,"abstract":"In studies evaluating ship performances running in actual seas, shaft powers, ship motions, strains, and the like are usually used. In addition to obtaining these physical quantities, determining the pressure distribution on hulls would be useful for rational ship design. However, the technique for measuring pressure distribution on a ship’s hull in the actual sea has not been established. Therefore, we propose a method to obtain pressure distribution through the convolution integral by using the pressure measured at only one point. The estimated pressure distribution is validated in comparison with measured experimental values. The estimated pressure is discussed in diffraction and free-motion tests. The effectiveness of the proposed method is further validated by integrating the estimated pressures on the hull surface. Then, the obtained forces or motions estimated from the forces are compared with directly measured values.","PeriodicalId":503139,"journal":{"name":"International Journal of Offshore and Polar Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140281208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.17736/ijope.2024.jc921
Jinichi Koue, Saori Shyu, Akihisa Abe
Offshore wind power has been currently attracting attention as part of the efforts of Sustainable Development Goals, and the cumulative installed capacity worldwide has increased more than 10-fold in the last decade. As the world’s energy sources shift from fossil to renewable energy, the increase of construction of offshore structures associated with marine development will likely generate undesirable underwater noise that is harmful to marine life living near construction sites. To reduce underwater noise and improve the marine acoustic environment, this study clarifies the generation mechanism and propagation behavior of underwater noise by pile driving and discusses how to reduce such noise.
{"title":"Experimental Investigation of Underwater Noise Generation Mechanism During Pile Driving","authors":"Jinichi Koue, Saori Shyu, Akihisa Abe","doi":"10.17736/ijope.2024.jc921","DOIUrl":"https://doi.org/10.17736/ijope.2024.jc921","url":null,"abstract":"Offshore wind power has been currently attracting attention as part of the efforts of Sustainable Development Goals, and the cumulative installed capacity worldwide has increased more than 10-fold in the last decade. As the world’s energy sources shift from fossil to renewable energy, the increase of construction of offshore structures associated with marine development will likely generate undesirable underwater noise that is harmful to marine life living near construction sites. To reduce underwater noise and improve the marine acoustic environment, this study clarifies the generation mechanism and propagation behavior of underwater noise by pile driving and discusses how to reduce such noise.","PeriodicalId":503139,"journal":{"name":"International Journal of Offshore and Polar Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140275921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.17736/ijope.2024.jc926
Nariman Afzali, Georjina Jabour, N. Stranghöner, P. Langenberg
Duplex stainless steels are highly suitable for steel structures exposed to both low temperatures and fatigue loading. It is essential to ensure the prevention of brittle fracture in low-temperature applications due to the toughness-temperature transition behavior exhibited by duplex stainless steel, which is similar to the behavior seen in carbon steel. The goal of this contribution is to introduce the development and validation of the Master Curve concept, along with demonstrating how the transition temperature correlation can be applied to duplex stainless steels through the utilization of experimental data obtained from fracture toughness and Charpy-V impact tests.
{"title":"An Investigation into the Correlation Between Fracture Toughness and Charpy Impact Test for Duplex Stainless Steels","authors":"Nariman Afzali, Georjina Jabour, N. Stranghöner, P. Langenberg","doi":"10.17736/ijope.2024.jc926","DOIUrl":"https://doi.org/10.17736/ijope.2024.jc926","url":null,"abstract":"Duplex stainless steels are highly suitable for steel structures exposed to both low temperatures and fatigue loading. It is essential to ensure the prevention of brittle fracture in low-temperature applications due to the toughness-temperature transition behavior exhibited by duplex stainless steel, which is similar to the behavior seen in carbon steel. The goal of this contribution is to introduce the development and validation of the Master Curve concept, along with demonstrating how the transition temperature correlation can be applied to duplex stainless steels through the utilization of experimental data obtained from fracture toughness and Charpy-V impact tests.","PeriodicalId":503139,"journal":{"name":"International Journal of Offshore and Polar Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140283285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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