This study aims to investigate the reshaping mechanisms of a reshaping berm breakwater by assessing the results of a 2D numerical model developed in OpenFoam®. The flow inside and outside the porous breakwater is numerically simulated. The initial and reshaped form of the breakwater is modelled using the Darcy-Forchheimer equation and k-ε closure models. The numerical model is calibrated with and validated against the experimental data of wave-induced pressure and water level fluctuations inside and outside the porous breakwater. Both initial and reshaped berm breakwater are assessed for calibration and validation processes. The result demonstrates that the minimum run-down level on the breakwater slope is a critical area in armor instability due to the outward driving forces; these forces are because of synchronizing excess pressure gradient and outward flow critically. Moreover, a parallel downward flow occurs during waves running down and can push the displaced armor down the slope. After reshaping, the breakwater profile has a milder slope than the initial profile and the outward forces due to excess pressure gradient is reduced to less than one-half of its initial amount due to the change in breaker type. As a result, the reshaped profile is modified to harmonize with new environmental conditions in the reshaping berm breakwater.
{"title":"Mechanism of wave-induced flow in reshaping breakwaters","authors":"Abbasali Rahmani, M. N. Moghim, M. Chamani","doi":"10.1680/jmaen.2021.013","DOIUrl":"https://doi.org/10.1680/jmaen.2021.013","url":null,"abstract":"This study aims to investigate the reshaping mechanisms of a reshaping berm breakwater by assessing the results of a 2D numerical model developed in OpenFoam®. The flow inside and outside the porous breakwater is numerically simulated. The initial and reshaped form of the breakwater is modelled using the Darcy-Forchheimer equation and k-ε closure models. The numerical model is calibrated with and validated against the experimental data of wave-induced pressure and water level fluctuations inside and outside the porous breakwater. Both initial and reshaped berm breakwater are assessed for calibration and validation processes. The result demonstrates that the minimum run-down level on the breakwater slope is a critical area in armor instability due to the outward driving forces; these forces are because of synchronizing excess pressure gradient and outward flow critically. Moreover, a parallel downward flow occurs during waves running down and can push the displaced armor down the slope. After reshaping, the breakwater profile has a milder slope than the initial profile and the outward forces due to excess pressure gradient is reduced to less than one-half of its initial amount due to the change in breaker type. As a result, the reshaped profile is modified to harmonize with new environmental conditions in the reshaping berm breakwater.","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"57 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91225869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The evaluation of wave runup on beaches is of significant importance since it is used in different coastal engineering and management applications, including the assessment of beach morphology, the determination of erosion and flooding risk, and the design and maintenance of coastal structures. The main aim of this paper is to present a new method of wave runup prediction which is intended to be applicable to the various types of natural beaches. A single formulation was established for beaches, which were categorized as dissipative, reflective and intermediate. This comprehensive parametric runup model, which included both wave setup and swash excursion, was specifically developed to represent the wide-ranging conditions experienced in the swash zone in terms of beach conditions. The runup model included a means to account for obliquely incident waves, varying foreshore sediment characteristics, the infiltration/exfiltration processes during swash events and used fitting parameters to account for other site-specific conditions. The novel runup model produced comparable results to other parametric models, and showed good correlation with laboratory data and limited field data. However, while the model was deemed suitable to be adopted at varying coastal sites, field data is required for implementation in order to yield meaningful output.
{"title":"A novel approach for predicting wave runup on natural beaches","authors":"D. Villarroel-Lamb","doi":"10.1680/jmaen.2021.022","DOIUrl":"https://doi.org/10.1680/jmaen.2021.022","url":null,"abstract":"The evaluation of wave runup on beaches is of significant importance since it is used in different coastal engineering and management applications, including the assessment of beach morphology, the determination of erosion and flooding risk, and the design and maintenance of coastal structures. The main aim of this paper is to present a new method of wave runup prediction which is intended to be applicable to the various types of natural beaches. A single formulation was established for beaches, which were categorized as dissipative, reflective and intermediate. This comprehensive parametric runup model, which included both wave setup and swash excursion, was specifically developed to represent the wide-ranging conditions experienced in the swash zone in terms of beach conditions. The runup model included a means to account for obliquely incident waves, varying foreshore sediment characteristics, the infiltration/exfiltration processes during swash events and used fitting parameters to account for other site-specific conditions. The novel runup model produced comparable results to other parametric models, and showed good correlation with laboratory data and limited field data. However, while the model was deemed suitable to be adopted at varying coastal sites, field data is required for implementation in order to yield meaningful output.","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"224 2 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86192319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the motivation to overcome the shortcomings of the traditional approaches, in this paper, we have proposed to utilize an exponentiated Weibull distribution for fitting the significant wave height data in order to more accurately calculate the sea state parameter distribution tails and to extrapolate well. Our proposal has been applied in predicting the probability distribution tails of a measured ocean wave dataset, and its accuracy has been clearly demonstrated. This proposal has subsequently been utilized in combination with Monte Carlo sampling to form a new environmental contour method for deriving a 50-year contour line based on the aforementioned measured ocean wave dataset. The derived environmental contour line has been compared with that predicted by using a traditional contour line approach, and the engineering significances of using a more reliable environmental contour line such as the one derived using our proposed new method for predicting the long-term design force values for an ocean sustainable energy system have been highlighted. In conclusion, our proposed new environmental contour method is recommended to be utilized for predicting the extreme dynamic response values for the safe and successful design of ocean sustainable energy systems.
{"title":"A new prediction method for reliability analysis of ocean sustainable energy systems","authors":"Yingguang Wang","doi":"10.1680/jmaen.2022.003","DOIUrl":"https://doi.org/10.1680/jmaen.2022.003","url":null,"abstract":"With the motivation to overcome the shortcomings of the traditional approaches, in this paper, we have proposed to utilize an exponentiated Weibull distribution for fitting the significant wave height data in order to more accurately calculate the sea state parameter distribution tails and to extrapolate well. Our proposal has been applied in predicting the probability distribution tails of a measured ocean wave dataset, and its accuracy has been clearly demonstrated. This proposal has subsequently been utilized in combination with Monte Carlo sampling to form a new environmental contour method for deriving a 50-year contour line based on the aforementioned measured ocean wave dataset. The derived environmental contour line has been compared with that predicted by using a traditional contour line approach, and the engineering significances of using a more reliable environmental contour line such as the one derived using our proposed new method for predicting the long-term design force values for an ocean sustainable energy system have been highlighted. In conclusion, our proposed new environmental contour method is recommended to be utilized for predicting the extreme dynamic response values for the safe and successful design of ocean sustainable energy systems.","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"42 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79904613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There is unequivocal evidence that global sea levels are rising. It is therefore inevitable there will be socio economic impacts as a result of this. To aid mitigation, and the implementation of adaptation measures, it is vital the magnitude of the potential impact is quantified. Current approaches in the UK make simplifying assumptions regarding the relationship between present day and future economic damages relating to coastal flood risk. The analysis undertaken here supports improved sea level rise impact studies by providing national-scale estimates of changes in wave overtopping rates and flood defence overflow rates, as a result of different amounts of sea level rise. The analysis involves the application of components of an existing risk-based coastal flood risk analysis method. A subset of almost 600 flood defence assets around the country have been analysed for sea level rise rates up to 1m. The resulting analysis shows that, on average, the wave overtopping rate increases by up to 150 times above present day rates for lower return periods and by up to 5 times for higher return periods. This differential arises as a result of non-linearities in overtopping rates with increasing extreme sea levels.
{"title":"Impacts of Sea Level Rise on wave overtopping rates around the coast of England","authors":"D. Hames, Isabel Vidal, B. Gouldby","doi":"10.1680/jmaen.2021.020","DOIUrl":"https://doi.org/10.1680/jmaen.2021.020","url":null,"abstract":"There is unequivocal evidence that global sea levels are rising. It is therefore inevitable there will be socio economic impacts as a result of this. To aid mitigation, and the implementation of adaptation measures, it is vital the magnitude of the potential impact is quantified. Current approaches in the UK make simplifying assumptions regarding the relationship between present day and future economic damages relating to coastal flood risk. The analysis undertaken here supports improved sea level rise impact studies by providing national-scale estimates of changes in wave overtopping rates and flood defence overflow rates, as a result of different amounts of sea level rise. The analysis involves the application of components of an existing risk-based coastal flood risk analysis method. A subset of almost 600 flood defence assets around the country have been analysed for sea level rise rates up to 1m. The resulting analysis shows that, on average, the wave overtopping rate increases by up to 150 times above present day rates for lower return periods and by up to 5 times for higher return periods. This differential arises as a result of non-linearities in overtopping rates with increasing extreme sea levels.","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"23 2 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77862525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In numerical modelling of scour around riverine and coastal structures using a hydro-morphodynamic model, a discrete sand sliding procedure needs to be implemented to avoid the occurrence of unrealistic bed profiles. In this study, two commonly employed sand sliding techniques, namely, the artificial transport rate method (ATRM) and the geometry-based method (GBM), are implemented in OpenFOAM and their performances are evaluated for five three-dimensional test cases. The test cases are classified into cases with and without sediment transport induced by a flow field. In the first three test cases, in the absence of a flow field, sand heap avalanches for different geometries and bed boundary grid structures are modelled to compare the methods in terms of simulation time and mass continuity. In test cases 4 and 5, in the presence of a flow field, the sensitivity of the sand sliding methods coupled with a hydro-morphodynamic model to different bed mesh structures is evaluated in modelling scour. The results of the analysis demonstrate that modelling of the sand sliding procedure using ATRM requires higher computational time, while its results are highly independent of the bed mesh structure with lower mass continuity error, <0.2% in all test cases, in comparison with GBM.
{"title":"Numerical investigation of sand sliding methods for hydro-morphodynamic modelling","authors":"Amir Bordbar, Soroosh Sharifi, Hassan Hemida","doi":"10.1680/jmaen.2021.016","DOIUrl":"https://doi.org/10.1680/jmaen.2021.016","url":null,"abstract":"In numerical modelling of scour around riverine and coastal structures using a hydro-morphodynamic model, a discrete sand sliding procedure needs to be implemented to avoid the occurrence of unrealistic bed profiles. In this study, two commonly employed sand sliding techniques, namely, the artificial transport rate method (ATRM) and the geometry-based method (GBM), are implemented in OpenFOAM and their performances are evaluated for five three-dimensional test cases. The test cases are classified into cases with and without sediment transport induced by a flow field. In the first three test cases, in the absence of a flow field, sand heap avalanches for different geometries and bed boundary grid structures are modelled to compare the methods in terms of simulation time and mass continuity. In test cases 4 and 5, in the presence of a flow field, the sensitivity of the sand sliding methods coupled with a hydro-morphodynamic model to different bed mesh structures is evaluated in modelling scour. The results of the analysis demonstrate that modelling of the sand sliding procedure using ATRM requires higher computational time, while its results are highly independent of the bed mesh structure with lower mass continuity error, <0.2% in all test cases, in comparison with GBM.","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138515801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the dynamic performance of a work ship with a mooring line failure was studied. A fully coupled dynamic analysis program ANSYS/AQWA was applied to simulate ship motions and mooring line dynamics. The first- and second-order wave excitation forces were calculated using the three-dimensional diffraction/radiation theory, and the behaviors of the mooring lines were analyzed using a nonlinear finite element method. Under the combined environmental loads of waves and wind, one mooring line was intentionally disconnected at a certain moment. Then, the dynamic response after the mooring line breaks, the energy distribution characteristics in the motion response spectrum and the mean tension variation of the remaining mooring lines were discussed. The results showed that a sudden failure of the mooring line significantly affected the performance of the ship. To ensure the structural integrity of the ship system and the safety of personnel on deck, the influence of a mooring line failure on the ship should be investigated in advance.
{"title":"The effects of one mooring line failure on the behavior of a work ship","authors":"H. Wu, Zhiyang Zhang","doi":"10.1680/jmaen.2021.011","DOIUrl":"https://doi.org/10.1680/jmaen.2021.011","url":null,"abstract":"In this paper, the dynamic performance of a work ship with a mooring line failure was studied. A fully coupled dynamic analysis program ANSYS/AQWA was applied to simulate ship motions and mooring line dynamics. The first- and second-order wave excitation forces were calculated using the three-dimensional diffraction/radiation theory, and the behaviors of the mooring lines were analyzed using a nonlinear finite element method. Under the combined environmental loads of waves and wind, one mooring line was intentionally disconnected at a certain moment. Then, the dynamic response after the mooring line breaks, the energy distribution characteristics in the motion response spectrum and the mean tension variation of the remaining mooring lines were discussed. The results showed that a sudden failure of the mooring line significantly affected the performance of the ship. To ensure the structural integrity of the ship system and the safety of personnel on deck, the influence of a mooring line failure on the ship should be investigated in advance.","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"28 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74495577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In container terminals equipped with shuttle vehicles, apron buffer zones are necessary for linking up the operations of quay cranes and shuttle vehicles. An integrated quay crane - shuttle vehicle scheduling problem with limited apron buffer capacity is investigated in this paper. This problem is subject to the practical constraints on nonzero traveling time, precedence relationships between container handling jobs, quay crane non-interference, safety margin, blocking, and apron buffer capacity constraint. The objective of this investigation is to minimize the makespan of vessel handling by simultaneous optimization of bay-to-quay crane assignment, the sequences of bays handled by quay cranes, the sequences of jobs handled by quay cranes, job-to-shuttle vehicle assignment and the sequences of jobs handled by shuttle vehicles. To achieve this, a mixed-integer linear programming model is first formulated to solve the scheduling problem. Second, the relationships of decision variables and model constraints are discussed to generate two sub-models: assignment-based and sequence-based. The assignment-based sub-model is developed from the proposed model by pre-determining the assignment of bay-to-quay cranes and job-to-shuttle vehicles, and the other is developed from the proposed model by pre-determining the sequences of jobs handled by each QC and each SV. Third, the hybrid genetic algorithms with the two sub-models are proposed. Fourth, numerical experiments show that the algorithms are competitive, compared to on-the-shelf solvers. Finally, practical implications of this investigation for apron buffer zone design are discussed.
{"title":"An integrated quay crane - shuttle vehicle scheduling problem with apron buffer capacity constraints","authors":"Yucan Yin, Y. Ge, Xin Wen, M. Zhong","doi":"10.1680/jmaen.2021.007","DOIUrl":"https://doi.org/10.1680/jmaen.2021.007","url":null,"abstract":"In container terminals equipped with shuttle vehicles, apron buffer zones are necessary for linking up the operations of quay cranes and shuttle vehicles. An integrated quay crane - shuttle vehicle scheduling problem with limited apron buffer capacity is investigated in this paper. This problem is subject to the practical constraints on nonzero traveling time, precedence relationships between container handling jobs, quay crane non-interference, safety margin, blocking, and apron buffer capacity constraint. The objective of this investigation is to minimize the makespan of vessel handling by simultaneous optimization of bay-to-quay crane assignment, the sequences of bays handled by quay cranes, the sequences of jobs handled by quay cranes, job-to-shuttle vehicle assignment and the sequences of jobs handled by shuttle vehicles. To achieve this, a mixed-integer linear programming model is first formulated to solve the scheduling problem. Second, the relationships of decision variables and model constraints are discussed to generate two sub-models: assignment-based and sequence-based. The assignment-based sub-model is developed from the proposed model by pre-determining the assignment of bay-to-quay cranes and job-to-shuttle vehicles, and the other is developed from the proposed model by pre-determining the sequences of jobs handled by each QC and each SV. Third, the hybrid genetic algorithms with the two sub-models are proposed. Fourth, numerical experiments show that the algorithms are competitive, compared to on-the-shelf solvers. Finally, practical implications of this investigation for apron buffer zone design are discussed.","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"9 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87001307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2022-06-01DOI: 10.1680/jmaen.2022.175.2.32
T. Fazeres-Ferradosa, T. Bruce, Facheng Wang
{"title":"Editorial: Connecting the land to the sea","authors":"T. Fazeres-Ferradosa, T. Bruce, Facheng Wang","doi":"10.1680/jmaen.2022.175.2.32","DOIUrl":"https://doi.org/10.1680/jmaen.2022.175.2.32","url":null,"abstract":"","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"8 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81911271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Much guidance has been published on the subject of structural modelling of bridge decks. However, limited guidance is available on the subject of structural modelling of suspended deck jetty structures. This paper reviews a number of common deck modelling methods to provide guidance specific to jetty deck analysis. It also investigates how orthotropic decks and typical jetty deck construction techniques can be accommodated within the modelling process. It is found that, as for bridge decks, the introduction of more powerful desktop computers and finite element software has largely removed the historically reported disadvantages of the finite element method. It also finds that the finite element method more accurately simulated the shear transfer in the slabs and axial forces in the crossbeams, and more accurately modelled the position of the combined section's neutral axis. Thus the finite element method provides a closer representation of the actual structure, leading to a better understanding of the structural behaviour. The finite element method also provides more accurate analyses when considering orthotropic decks and/or construction sequences.
{"title":"Analysis of a Suspended Deck Jetty using Grillage and Finite Element Analysis Methods","authors":"Ben R. Bullock","doi":"10.1680/jmaen.2021.015","DOIUrl":"https://doi.org/10.1680/jmaen.2021.015","url":null,"abstract":"Much guidance has been published on the subject of structural modelling of bridge decks. However, limited guidance is available on the subject of structural modelling of suspended deck jetty structures. This paper reviews a number of common deck modelling methods to provide guidance specific to jetty deck analysis. It also investigates how orthotropic decks and typical jetty deck construction techniques can be accommodated within the modelling process. It is found that, as for bridge decks, the introduction of more powerful desktop computers and finite element software has largely removed the historically reported disadvantages of the finite element method. It also finds that the finite element method more accurately simulated the shear transfer in the slabs and axial forces in the crossbeams, and more accurately modelled the position of the combined section's neutral axis. Thus the finite element method provides a closer representation of the actual structure, leading to a better understanding of the structural behaviour. The finite element method also provides more accurate analyses when considering orthotropic decks and/or construction sequences.","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"10 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89123553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the motivation to overcome the shortcomings of the Rosenblatt Inverse-First-Order Reliability environmental contour method, in this study, the use of bivariate kernel density estimation with smoothed cross-validation bandwidth selection method is proposed for generating more accurate environmental contour lines. The environmental contour lines at a chosen offshore site obtained by using the proposed new method were compared with those obtained by using the Rosenblatt Inverse-First-Order Reliability environmental contour method, and the accuracy and effectiveness of the proposed new method have been fully and clearly substantiated. Next, the 50-year extreme structural dynamic responses of a monopile-supported 5MW offshore wind turbine installed at this chosen offshore site based on the proposed new method and the Rosenblatt Inverse-First-Order Reliability environmental contour approach were calculated. Analyzing the calculating results, it can be found that the 50-year extreme fore-aft shear force value based on the 50-year extreme sea state obtained using the proposed new method is 78.9% larger than the corresponding value obtained based on the Rosenblatt Inverse-First-Order Reliability contour method. The calculation results in this paper were further systematically analyzed and compared, and the necessity and importance of using more realistic environmental contour lines (such as those generated using the proposed new method) have been finally highlighted.
{"title":"A new method for structural safety and reliability analysis of offshore wind turbines","authors":"Yingguang Wang","doi":"10.1680/jmaen.2021.019","DOIUrl":"https://doi.org/10.1680/jmaen.2021.019","url":null,"abstract":"With the motivation to overcome the shortcomings of the Rosenblatt Inverse-First-Order Reliability environmental contour method, in this study, the use of bivariate kernel density estimation with smoothed cross-validation bandwidth selection method is proposed for generating more accurate environmental contour lines. The environmental contour lines at a chosen offshore site obtained by using the proposed new method were compared with those obtained by using the Rosenblatt Inverse-First-Order Reliability environmental contour method, and the accuracy and effectiveness of the proposed new method have been fully and clearly substantiated. Next, the 50-year extreme structural dynamic responses of a monopile-supported 5MW offshore wind turbine installed at this chosen offshore site based on the proposed new method and the Rosenblatt Inverse-First-Order Reliability environmental contour approach were calculated. Analyzing the calculating results, it can be found that the 50-year extreme fore-aft shear force value based on the 50-year extreme sea state obtained using the proposed new method is 78.9% larger than the corresponding value obtained based on the Rosenblatt Inverse-First-Order Reliability contour method. The calculation results in this paper were further systematically analyzed and compared, and the necessity and importance of using more realistic environmental contour lines (such as those generated using the proposed new method) have been finally highlighted.","PeriodicalId":54575,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Maritime Engineering","volume":"99 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2021-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81415798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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