Pub Date : 2022-11-28DOI: 10.5750/ijme.v164ia2.730
S. Turnock, Son Hoang, Steven J. Ossont, J. Downes, Joseph Lam, Ben Pritchard
It is expected that a key part of a future with increasing use of maritime autonomous systems, will require collaborative and integrated approaches to working. How such approaches can be developed and tested was the focus of the Integrated Mission Management System 2019 (IMMS2019) project. The immediate objective was to experimentally demonstrate the ability of a single mission management system to control a fleet of heterogeneous, multi-domain autonomous platforms whereby their collaborative mission could be planned, verified, and delivered. To challenge the various spatial-temporal-energetic-communication-environmental constraints when operating such a fleet, real-world demonstration trials were carried out in Plymouth sound deployed from the Thales Maritime Autonomy Centre at Turnchapel Wharf. The trials were focussed on providing essential information into how such collaborations can be best executed, alongside invaluable lessons as to how existing platforms need to enhance their interoperability and in particular, robustness of communications and mission plans.
{"title":"AN EXPERIMENTAL APPROACH TO THE CHALLENGES OF MISSION PLANNING FOR COLLABORATIVE MARITIME AUTONOMY","authors":"S. Turnock, Son Hoang, Steven J. Ossont, J. Downes, Joseph Lam, Ben Pritchard","doi":"10.5750/ijme.v164ia2.730","DOIUrl":"https://doi.org/10.5750/ijme.v164ia2.730","url":null,"abstract":"It is expected that a key part of a future with increasing use of maritime autonomous systems, will require collaborative and integrated approaches to working. How such approaches can be developed and tested was the focus of the Integrated Mission Management System 2019 (IMMS2019) project. The immediate objective was to experimentally demonstrate the ability of a single mission management system to control a fleet of heterogeneous, multi-domain autonomous platforms whereby their collaborative mission could be planned, verified, and delivered. To challenge the various spatial-temporal-energetic-communication-environmental constraints when operating such a fleet, real-world demonstration trials were carried out in Plymouth sound deployed from the Thales Maritime Autonomy Centre at Turnchapel Wharf. The trials were focussed on providing essential information into how such collaborations can be best executed, alongside invaluable lessons as to how existing platforms need to enhance their interoperability and in particular, robustness of communications and mission plans.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48859442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2022-11-28DOI: 10.5750/ijme.v164ia2.1157
Shen Li, Do Kyun Kim, J. Ringsberg, B. Liu, S. Benson
The engineering modelling of ship hull girder strength usually consists of global and local levels. The Smith-type progressive collapse method is a typical example of this kind, in which the global model requires input from the local model with the underpinning local structural behaviour, i.e., load-shortening curve (LSC). However, the modelling is prone to uncertainty due to the statistical variability of the basic variables (aleatoric uncertainty) and the inadequacy of engineering models in both global and local levels (epistemic uncertainty). The former can be well tackled by a probabilistic sampling, whereas dealing with the latter for ship hull girder strength lacks an established approach. There can be different sources of epistemic uncertainty. In the modelling of ship hull girder strength, this may be partially manifested as that caused by different choices of local engineering models for predicting the LSC. In the light of this, a probabilistic method is applied in this research to investigate and quantify the uncertainty related to the local models. The adopted approach is a hybrid method incorporating the Smith-type progressive collapse method with Monte-Carlo Simulation and an adaptable LSC algorithm. Case studies on four merchant ships show that the ultimate strength in sagging is subjected to the most significant computational uncertainty as compared with those in hogging and horizontal bending. In a bi-axial load case, the computational uncertainty estimated for vertical bending will be counteracted as the horizontal bending increases. Nevertheless, this change is not directly proportional to the bi-axial load component ratio and appreciably varies between different ship types. The insights and data provided by this study may eventually resolve the epistemic uncertainty in the modelling of ship hull girder strength. It would also be useful to improve the ultimate limit state-based reliability analysis with regards to the strength model uncertainty evaluation.
{"title":"Uncertainty Of Ship Hull Girder Ultimate Strength in Longitudinal Bending","authors":"Shen Li, Do Kyun Kim, J. Ringsberg, B. Liu, S. Benson","doi":"10.5750/ijme.v164ia2.1157","DOIUrl":"https://doi.org/10.5750/ijme.v164ia2.1157","url":null,"abstract":"The engineering modelling of ship hull girder strength usually consists of global and local levels. The Smith-type progressive collapse method is a typical example of this kind, in which the global model requires input from the local model with the underpinning local structural behaviour, i.e., load-shortening curve (LSC). However, the modelling is prone to uncertainty due to the statistical variability of the basic variables (aleatoric uncertainty) and the inadequacy of engineering models in both global and local levels (epistemic uncertainty). The former can be well tackled by a probabilistic sampling, whereas dealing with the latter for ship hull girder strength lacks an established approach. There can be different sources of epistemic uncertainty. In the modelling of ship hull girder strength, this may be partially manifested as that caused by different choices of local engineering models for predicting the LSC. In the light of this, a probabilistic method is applied in this research to investigate and quantify the uncertainty related to the local models. The adopted approach is a hybrid method incorporating the Smith-type progressive collapse method with Monte-Carlo Simulation and an adaptable LSC algorithm. Case studies on four merchant ships show that the ultimate strength in sagging is subjected to the most significant computational uncertainty as compared with those in hogging and horizontal bending. In a bi-axial load case, the computational uncertainty estimated for vertical bending will be counteracted as the horizontal bending increases. Nevertheless, this change is not directly proportional to the bi-axial load component ratio and appreciably varies between different ship types. The insights and data provided by this study may eventually resolve the epistemic uncertainty in the modelling of ship hull girder strength. It would also be useful to improve the ultimate limit state-based reliability analysis with regards to the strength model uncertainty evaluation.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44480718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2022-11-28DOI: 10.5750/ijme.v164ia2.778
M. Mollaoğlu, H. Demirel, A. Balin
Industry 4.0 technology has affected almost every sector in the world. Maritime sector is one of them that were affected by this technology. In this study, components of the maritime sector were prioritized to find out which of them should comply with this transformation primarily. Many different criteria were taken into consideration for the solution of such problems. Therefore, multi-criteria decision-making (MCDM) methods required to solve this problem. Fuzzy AHP (Analytic Hierarchy Process) and VIKOR (VlseKriterijumska Optimizacijia I Kompromisno Resenje) hybrid method was employed for revealing the prioritization ranking for maritime sector components. A group of experts assessed and compared 22 criteria and scored them for each alternative. Proposed methodology was employed through the experts’ assessments. Results were displayed and suggestions were given for the further studies
工业4.0技术几乎影响了世界上的每一个领域。海事部门是受到这项技术影响的部门之一。在这项研究中，海事部门的组成部分被列为优先事项，以确定其中哪些部门应主要遵守这一转变。为了解决这些问题，考虑了许多不同的标准。因此，需要多准则决策（MCDM）方法来解决这一问题。采用模糊层次分析法（AHP）和VIKOR（VlseKriterijumska Optimizacijia I Kombrissino Resenje）混合方法揭示了海事部门组成部分的优先级排序。一组专家对22项标准进行了评估和比较，并对每一项备选标准进行了评分。通过专家评估采用了拟议的方法。展示了结果，并为进一步研究提出了建议
{"title":"EVALUATION OF THE EFFECTS OF INDUSTRY 4.0 ON THE MARITIME SECTOR WITH FUZZY AHP – VIKOR HYBRID METHOD","authors":"M. Mollaoğlu, H. Demirel, A. Balin","doi":"10.5750/ijme.v164ia2.778","DOIUrl":"https://doi.org/10.5750/ijme.v164ia2.778","url":null,"abstract":"Industry 4.0 technology has affected almost every sector in the world. Maritime sector is one of them that were affected by this technology. In this study, components of the maritime sector were prioritized to find out which of them should comply with this transformation primarily. Many different criteria were taken into consideration for the solution of such problems. Therefore, multi-criteria decision-making (MCDM) methods required to solve this problem. Fuzzy AHP (Analytic Hierarchy Process) and VIKOR (VlseKriterijumska Optimizacijia I Kompromisno Resenje) hybrid method was employed for revealing the prioritization ranking for maritime sector components. A group of experts assessed and compared 22 criteria and scored them for each alternative. Proposed methodology was employed through the experts’ assessments. Results were displayed and suggestions were given for the further studies","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46301864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2022-11-28DOI: 10.5750/ijme.v164ia2.1178
Jean-Baptiste R. G. Souppez, Juli Laci
Glass fibre reinforced polymer composites are the most common materials employed for the manufacturing of small crafts. Their hull construction and scantlings are governed by the ISO 12215-5. The latest version of the standard introduced a new methodology to assess the ultimate strength of composites laminates. The regression equations based on the fibre weight fraction of the former version have been replaced by a more detailed ply-by-ply analysis. However, no validation data is available to ascertain the relevance of the default ultimate strengths provided by the ISO 12215-5:2019. This paper employs destructive testing to experimentally characterize the ultimate flexural, tensile and compressive strength of a quasi-isotropic glass-epoxy laminate. Experiments were undertaken in accordance with the ISO 178 for flexural properties, the ISO 527-4 for tensile properties, and the ISO 14126 for compressive properties. Two manufacturing techniques are investigated, namely hand lamination and vacuum bagging. The former represents a cheaper and therefore more common manufacturing option, while the latter is representative of an advanced manufacturing process. The key results show that the ISO 12215-5:2019 default ultimate strengths for the quasi-isotropic composite laminate tested are (i) conservative for the ultimate flexural strength, (ii) appropriate for the ultimate tensile strength, and (iii) optimistic for the ultimate compressive strength, especially for vacuum bagged samples, with the main cause identified as the value of the ultimate compressive breaking strain for chopped strand mat. These findings provide validation data for the ISO12215-5:2019. They may inform designers, compliance assessors and policy makers in the selection of relevant factors of safety for composite structures, and it is anticipated the results may contribute to future improvements in small craft regulations.
{"title":"EXPERIMENTAL CHARACTERIZATION OF THE STRENGTH OF HAND-LAMINATED AND VACUUM BAGGED QUASI-ISOTROPIC GLASS-EPOXY COMPOSITES AGAISNT THE ISO 12215-5","authors":"Jean-Baptiste R. G. Souppez, Juli Laci","doi":"10.5750/ijme.v164ia2.1178","DOIUrl":"https://doi.org/10.5750/ijme.v164ia2.1178","url":null,"abstract":"Glass fibre reinforced polymer composites are the most common materials employed for the manufacturing of small crafts. Their hull construction and scantlings are governed by the ISO 12215-5. The latest version of the standard introduced a new methodology to assess the ultimate strength of composites laminates. The regression equations based on the fibre weight fraction of the former version have been replaced by a more detailed ply-by-ply analysis. However, no validation data is available to ascertain the relevance of the default ultimate strengths provided by the ISO 12215-5:2019. This paper employs destructive testing to experimentally characterize the ultimate flexural, tensile and compressive strength of a quasi-isotropic glass-epoxy laminate. Experiments were undertaken in accordance with the ISO 178 for flexural properties, the ISO 527-4 for tensile properties, and the ISO 14126 for compressive properties. Two manufacturing techniques are investigated, namely hand lamination and vacuum bagging. The former represents a cheaper and therefore more common manufacturing option, while the latter is representative of an advanced manufacturing process. The key results show that the ISO 12215-5:2019 default ultimate strengths for the quasi-isotropic composite laminate tested are (i) conservative for the ultimate flexural strength, (ii) appropriate for the ultimate tensile strength, and (iii) optimistic for the ultimate compressive strength, especially for vacuum bagged samples, with the main cause identified as the value of the ultimate compressive breaking strain for chopped strand mat. These findings provide validation data for the ISO12215-5:2019. They may inform designers, compliance assessors and policy makers in the selection of relevant factors of safety for composite structures, and it is anticipated the results may contribute to future improvements in small craft regulations.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44785665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The objective of this research is to analyse smart technologies implemented in marinas and their impact upon the safety and service quality improvement, sustainability, and environmental protection, as well as energy consumption and operations optimization. KPI and a definition of smart marina concept have been derived based on the smart port concept. The analysis has been conducted on a sample of 78 marinas. Ultimately, the scientific analysis has been performed in order to determine the advantages and disadvantages of introducing smart technologies in marina management. The results indicate that the marinas are undergoing a revolution in terms of facilitating booking management process and achieving greater safety and service quality, but still need to improve in the field of monitoring and controlling nautical tourism impact upon the environment.
{"title":"Smart Technology Applied in The Management of Yachting Marinas","authors":"Ana B. Radulovic","doi":"10.5750/ijme.v164i1.816","DOIUrl":"https://doi.org/10.5750/ijme.v164i1.816","url":null,"abstract":"The objective of this research is to analyse smart technologies implemented in marinas and their impact upon the safety and service quality improvement, sustainability, and environmental protection, as well as energy consumption and operations optimization. KPI and a definition of smart marina concept have been derived based on the smart port concept. The analysis has been conducted on a sample of 78 marinas. Ultimately, the scientific analysis has been performed in order to determine the advantages and disadvantages of introducing smart technologies in marina management. The results indicate that the marinas are undergoing a revolution in terms of facilitating booking management process and achieving greater safety and service quality, but still need to improve in the field of monitoring and controlling nautical tourism impact upon the environment.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48325356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper contains a literature review of technologies employed in the scientific literature to provide data on ice severity to augment situational awareness of human operators (aboard a ship or in a remote control center) and eventually autonomous navigation algorithms. As ships navigate in ice, masters use a wide source of information to assess the ice conditions along their planned route. This information is used to make ongoing assessments of the ice severity and to decide how to optimize the route to avoid damage to the ship, besetting, etc. Typically, this assessment is made by the officers in charge of the ship based on observations, experience, and metocean publications such as weather forecasts and ice charts. Significant levels of experience needed to safely assess and navigate in complex or severe ice conditions. A fundamental challenge in allowing autonomy or decision-support for navigation of ice-covered waters is providing accurate and relevant ice severity data that feeds decision-making.
{"title":"Ice Sensing Technologies with Applications in Augmented Situational Awareness","authors":"M. Garvin","doi":"10.5750/ijme.v164i1.18","DOIUrl":"https://doi.org/10.5750/ijme.v164i1.18","url":null,"abstract":"This paper contains a literature review of technologies employed in the scientific literature to provide data on ice severity to augment situational awareness of human operators (aboard a ship or in a remote control center) and eventually autonomous navigation algorithms. As ships navigate in ice, masters use a wide source of information to assess the ice conditions along their planned route. This information is used to make ongoing assessments of the ice severity and to decide how to optimize the route to avoid damage to the ship, besetting, etc. Typically, this assessment is made by the officers in charge of the ship based on observations, experience, and metocean publications such as weather forecasts and ice charts. Significant levels of experience needed to safely assess and navigate in complex or severe ice conditions. A fundamental challenge in allowing autonomy or decision-support for navigation of ice-covered waters is providing accurate and relevant ice severity data that feeds decision-making.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44013092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the numerical study on the hydrodynamic coefficients of the submarine hull form “DARPA SUBOFF” when deeply submerged and near the free surface when travelling straight ahead and at a range of drift angles. The Computational Fluid Dynamics (CFD)-based numerical model was validated with experimental data existing in the public domain for the SUBOFF, travelling over a range of drift angles when deeply submerged at a constant speed and in a straight line near the free surface over a range of speeds. The free surface effect on the hydrodynamic behaviour of the SUBOFF was then investigated throughout a range of speeds, drift angles and submergence depths. Results show that the effects of the free surface diminish rapidly with submergence and the near free surface hydrodynamic behaviour of the SUBOFF is highly Froude number dependent.
{"title":"Free Surface Effect on the Hydrodynamics of an Underwater Vehicle Hullform, the Darpa Suboff","authors":"X. Ling, Z. Leong, C. Chin, M. Woodward","doi":"10.5750/ijme.v164i1.732","DOIUrl":"https://doi.org/10.5750/ijme.v164i1.732","url":null,"abstract":"This paper presents the numerical study on the hydrodynamic coefficients of the submarine hull form “DARPA SUBOFF” when deeply submerged and near the free surface when travelling straight ahead and at a range of drift angles. The Computational Fluid Dynamics (CFD)-based numerical model was validated with experimental data existing in the public domain for the SUBOFF, travelling over a range of drift angles when deeply submerged at a constant speed and in a straight line near the free surface over a range of speeds. The free surface effect on the hydrodynamic behaviour of the SUBOFF was then investigated throughout a range of speeds, drift angles and submergence depths. Results show that the effects of the free surface diminish rapidly with submergence and the near free surface hydrodynamic behaviour of the SUBOFF is highly Froude number dependent.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49151487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maintenance and repair of ship systems and prediction of fault probability have become an important issue for dynamic ship systems recently. Increasing the usability of systems by detecting the fault analysis is one of the current work areas. In recent years, the rapid development of information technologies and the machine learning approaches developing accordingly have made it possible to integrate machine learning techniques into ship systems. The use of machine learning in the studies has enabled this method to be tested in the areas of maintenance, repair, and fault analysis. To be able to predict the fault that may occur in the ship machinery systems and prevent the fault accordingly, can increase the lifespan of ship machinery's. In this study, the data obtained from an LM-2500 type ship engine were analyzed by regression and Artificial Neural Networks (ANN) algorithms to predict the fault of ship machinery. The results were compared for linear regression, decision tree regression, k nearest neighbours’ regression, random forest regression, bayesian ridge regression, extra tree regression, linear SVR regression and ANN algorithms. As a result of the analysis, it was revealed that the ANN method gave better results in machine fault prediction compared to the regression methods.
{"title":"Fault Analysis of Ship Machinery Using Machine Learning Techniques","authors":"Funda Kaya İnceişçi, A. Ak","doi":"10.5750/ijme.v164i1.769","DOIUrl":"https://doi.org/10.5750/ijme.v164i1.769","url":null,"abstract":"Maintenance and repair of ship systems and prediction of fault probability have become an important issue for dynamic ship systems recently. Increasing the usability of systems by detecting the fault analysis is one of the current work areas. In recent years, the rapid development of information technologies and the machine learning approaches developing accordingly have made it possible to integrate machine learning techniques into ship systems. The use of machine learning in the studies has enabled this method to be tested in the areas of maintenance, repair, and fault analysis. To be able to predict the fault that may occur in the ship machinery systems and prevent the fault accordingly, can increase the lifespan of ship machinery's. In this study, the data obtained from an LM-2500 type ship engine were analyzed by regression and Artificial Neural Networks (ANN) algorithms to predict the fault of ship machinery. The results were compared for linear regression, decision tree regression, k nearest neighbours’ regression, random forest regression, bayesian ridge regression, extra tree regression, linear SVR regression and ANN algorithms. As a result of the analysis, it was revealed that the ANN method gave better results in machine fault prediction compared to the regression methods. ","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43978662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mathieu Courdier, Z. Leong, J. Duffy, J. Binns, A. Conway
Underwater Vehicles (UV) are required to travel on the surface for periods of time to complete mission requirements. However, knowledge on the drag of a surfaced UV is scarce in the public domain and the knowledge on the behaviour of surface craft is generally not applicable due to substantial differences in hull form. This paper presents a numerical study on the drag coefficient of a surfaced and fully appended BB2 UV in calm water. The results were firstly validated with the available experimental drag data for a range of speeds. Secondly, the free surface elevation along the length of the UV photographed during physical model scale experiments is compared to the free surface elevation predicted by CFD. This research has shown that a multiphase CFD model can accurately predict the drag due to the forward motion of a surfaced UV in calm water.
{"title":"Numerical Validation of the Hydrodynamic Drag of a Surfaced and Fully Appended Underwater Vehicle","authors":"Mathieu Courdier, Z. Leong, J. Duffy, J. Binns, A. Conway","doi":"10.5750/ijme.v164i1.24","DOIUrl":"https://doi.org/10.5750/ijme.v164i1.24","url":null,"abstract":"Underwater Vehicles (UV) are required to travel on the surface for periods of time to complete mission requirements. However, knowledge on the drag of a surfaced UV is scarce in the public domain and the knowledge on the behaviour of surface craft is generally not applicable due to substantial differences in hull form. This paper presents a numerical study on the drag coefficient of a surfaced and fully appended BB2 UV in calm water. The results were firstly validated with the available experimental drag data for a range of speeds. Secondly, the free surface elevation along the length of the UV photographed during physical model scale experiments is compared to the free surface elevation predicted by CFD. This research has shown that a multiphase CFD model can accurately predict the drag due to the forward motion of a surfaced UV in calm water.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41547841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Warren, J. Ali-Lavroff, J. McVicar, T. Magoga, B. Shabani, D. Holloway, G. Thomas
The estimation of fatigue life in the design process is particularly important for weight-optimised ships such as high-speed aluminium craft, but to date no research has been published on the fatigue accumulation on large wave-piercing catamarans, focusing on long-term operations. This paper assesses the applicability of classification society rules for high-speed catamarans with respect to fatigue design. This was achieved by comparing the long-term distributions of stress, measured on a 111m long wave-piercing catamaran ferry whilst operating in the Canary Islands and during the delivery voyage, with load spectra estimated using a method accepted by the classification society, DNV. The paper also proposes an improved distribution fitment method for fatigue analysis. A detailed method to convert measured stress histories in the time domain into an appropriate stress-spectrum and fitment of Weibull parameters is presented. Results show that the simplified method accepted by the classification society is highly conservative regarding fatigue estimation compared to fatigue results based on measured data. The proposed combined Weibull fitment method substantially improves the accuracy of simplified fatigue analysis methods.
{"title":"Fatigue Estimation on a High-Speed Wave Piercing Catamaran During Normal Operations","authors":"M. Warren, J. Ali-Lavroff, J. McVicar, T. Magoga, B. Shabani, D. Holloway, G. Thomas","doi":"10.5750/ijme.v164i1.736","DOIUrl":"https://doi.org/10.5750/ijme.v164i1.736","url":null,"abstract":"The estimation of fatigue life in the design process is particularly important for weight-optimised ships such as high-speed aluminium craft, but to date no research has been published on the fatigue accumulation on large wave-piercing catamarans, focusing on long-term operations. This paper assesses the applicability of classification society rules for high-speed catamarans with respect to fatigue design. This was achieved by comparing the long-term distributions of stress, measured on a 111m long wave-piercing catamaran ferry whilst operating in the Canary Islands and during the delivery voyage, with load spectra estimated using a method accepted by the classification society, DNV. The paper also proposes an improved distribution fitment method for fatigue analysis. A detailed method to convert measured stress histories in the time domain into an appropriate stress-spectrum and fitment of Weibull parameters is presented. Results show that the simplified method accepted by the classification society is highly conservative regarding fatigue estimation compared to fatigue results based on measured data. The proposed combined Weibull fitment method substantially improves the accuracy of simplified fatigue analysis methods.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42671418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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