Pub Date : 2022-11-29DOI: 10.1080/09377255.2022.2149090
Z. Kok, J. Duffy, S. Chai, Yuting Jin
ABSTRACT An extensive Computational Fluid Dynamics (CFD) based study has been undertaken to develop a set of empirical formulae for squat prediction suitable for modern container ships in laterally-unrestricted shallow water. Previous work has quantified the effect of various ship principal particulars on midship sinkage and trim. The current study expands on the previous work to provide further quantifications for ship speed and water depth. Multiple linear regression analysis is then performed on the dataset to produce empirical equations for sinkage and trim. Predictions using the new set of formulae correlate well with the original dataset as well as new datasets which are within the limits of applicability. Predictions using the new formulae tend to be more accurate than existing empirical methods for the cases tested. Hence, the new set of formulae is a useful tool to provide reliable, rapid squat assessment and is suitable for implementation into real-time ship-handling simulator mathematical models.
{"title":"CFD-based empirical formulae for squat prediction of modern container ships","authors":"Z. Kok, J. Duffy, S. Chai, Yuting Jin","doi":"10.1080/09377255.2022.2149090","DOIUrl":"https://doi.org/10.1080/09377255.2022.2149090","url":null,"abstract":"ABSTRACT An extensive Computational Fluid Dynamics (CFD) based study has been undertaken to develop a set of empirical formulae for squat prediction suitable for modern container ships in laterally-unrestricted shallow water. Previous work has quantified the effect of various ship principal particulars on midship sinkage and trim. The current study expands on the previous work to provide further quantifications for ship speed and water depth. Multiple linear regression analysis is then performed on the dataset to produce empirical equations for sinkage and trim. Predictions using the new set of formulae correlate well with the original dataset as well as new datasets which are within the limits of applicability. Predictions using the new formulae tend to be more accurate than existing empirical methods for the cases tested. Hence, the new set of formulae is a useful tool to provide reliable, rapid squat assessment and is suitable for implementation into real-time ship-handling simulator mathematical models.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41787176","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 : 2022-11-23DOI: 10.1080/09377255.2022.2149094
R. Suzuki, Y. Tsukada, M. Ueno
ABSTRACT We investigated the effects of the steady wave force variations generated by oblique motions upon ship manoeuvre estimations, using a numerical simulation that incorporated only steady wave forces into a three-degrees-of-freedom conventional modular mathematical model in calm water. The investigation was conducted for a very large crude carrier undergoing course-keeping manoeuvres in regular short waves. The steady wave forces in the simulation were provided via two methods, depending on the experimental data and the presence or absence of a ship drift angle. The simulation was validated via a free-running model test; this involved various rudder effectiveness conditions for the ship model and full-scale ships, both with and without engine limits. Through this validation, we showed that the steady wave force variations generated by oblique motions are non-negligible when accurately estimating the manoeuvres of full-scale ships in short waves, although they are negligible for ship models.
{"title":"Effects of steady wave forces on course-keeping manoeuvres of full- and model-scale ships moving obliquely in short waves","authors":"R. Suzuki, Y. Tsukada, M. Ueno","doi":"10.1080/09377255.2022.2149094","DOIUrl":"https://doi.org/10.1080/09377255.2022.2149094","url":null,"abstract":"ABSTRACT We investigated the effects of the steady wave force variations generated by oblique motions upon ship manoeuvre estimations, using a numerical simulation that incorporated only steady wave forces into a three-degrees-of-freedom conventional modular mathematical model in calm water. The investigation was conducted for a very large crude carrier undergoing course-keeping manoeuvres in regular short waves. The steady wave forces in the simulation were provided via two methods, depending on the experimental data and the presence or absence of a ship drift angle. The simulation was validated via a free-running model test; this involved various rudder effectiveness conditions for the ship model and full-scale ships, both with and without engine limits. Through this validation, we showed that the steady wave force variations generated by oblique motions are non-negligible when accurately estimating the manoeuvres of full-scale ships in short waves, although they are negligible for ship models.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42064808","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 : 2022-10-28DOI: 10.1080/09377255.2022.2115241
D. Fuentes, A. Cura Hochbaum, R. Schulze
ABSTRACT The increasing interest in using flexible materials to design marine propellers, considering deformations due to flow loads. A numerical procedure for analysing two-way fluid-structure interactions, based on the commercial STAR-CCM+ multiphysics software, is described and applied to predict the hydroelastic response of the flexible marine propeller P1790 to hydrodynamic forces in open water conditions. The influence of the deformation on the performance of the flexible propeller was analysed by comparison with its rigid counterpart. The procedure has been validated by means of experiments performed in the cavitation tunnel K27 of the Technical University Berlin with both, the flexible and the rigid propeller. The predicted performance coefficients and the axial deformation of the blades agree well with measured values. This suggests the feasibility of using the passive bending and twisting behaviour of a flexible propeller to adapt the pressure distribution on the blade to improve the propeller performance over a range of advance ratios.
{"title":"Numerical and experimental fluid–structure interaction analysis of a flexible propeller","authors":"D. Fuentes, A. Cura Hochbaum, R. Schulze","doi":"10.1080/09377255.2022.2115241","DOIUrl":"https://doi.org/10.1080/09377255.2022.2115241","url":null,"abstract":"ABSTRACT The increasing interest in using flexible materials to design marine propellers, considering deformations due to flow loads. A numerical procedure for analysing two-way fluid-structure interactions, based on the commercial STAR-CCM+ multiphysics software, is described and applied to predict the hydroelastic response of the flexible marine propeller P1790 to hydrodynamic forces in open water conditions. The influence of the deformation on the performance of the flexible propeller was analysed by comparison with its rigid counterpart. The procedure has been validated by means of experiments performed in the cavitation tunnel K27 of the Technical University Berlin with both, the flexible and the rigid propeller. The predicted performance coefficients and the axial deformation of the blades agree well with measured values. This suggests the feasibility of using the passive bending and twisting behaviour of a flexible propeller to adapt the pressure distribution on the blade to improve the propeller performance over a range of advance ratios.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47782011","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 : 2022-09-21DOI: 10.1080/09377255.2022.2117496
G. Kapsenberg, N. Carette
ABSTRACT This article presents practical methods to design an Anti-Roll tank (ART) for a ship and to predict the performance of the system ship + ART in a sea state. The methods presented are extensions of existing mathematical models. The prediction of the moment exerted by the tanks has been improved and new models for the lateral force have been derived. Instead of using only the roll angle, a combination of the roll angle and the local lateral acceleration is used as excitation of the motion of the tank. The main advantage of this combined parameter is that it accounts for the distance of the tank bottom to the roll axis and the effect of sway. Experimental and CFD methods have been reviewed and results are shown. Limits of the use of the U and FS-type of ART are separately discussed and quantified. The procedure is demonstrated by a design example.
{"title":"A consistent method to design and evaluate the performance of Anti-Roll Tanks for ships","authors":"G. Kapsenberg, N. Carette","doi":"10.1080/09377255.2022.2117496","DOIUrl":"https://doi.org/10.1080/09377255.2022.2117496","url":null,"abstract":"ABSTRACT This article presents practical methods to design an Anti-Roll tank (ART) for a ship and to predict the performance of the system ship + ART in a sea state. The methods presented are extensions of existing mathematical models. The prediction of the moment exerted by the tanks has been improved and new models for the lateral force have been derived. Instead of using only the roll angle, a combination of the roll angle and the local lateral acceleration is used as excitation of the motion of the tank. The main advantage of this combined parameter is that it accounts for the distance of the tank bottom to the roll axis and the effect of sway. Experimental and CFD methods have been reviewed and results are shown. Limits of the use of the U and FS-type of ART are separately discussed and quantified. The procedure is demonstrated by a design example.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49314127","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 : 2022-08-22DOI: 10.1080/09377255.2022.2109327
G. Nikolaidis, N. Themelis
ABSTRACT The quantification of the effect of ship design measures on its energy efficiency during real operation and using data-driven models is presented. Data collected from automated logging and meteorological service provider, received before and after the ship retrofit are utilized. Initially, a data preparation analysis is carried out and the input variables for the prediction of the main engine’s fuel oil consumption are selected. Afterwards, artificial neural networks (ANNs) design techniques are investigated utilizing modern machine learning methods. The generalization competence of a model is assessed based on its efficiency to cope with data that were not used in its training. Furthermore, the accuracy achieved by models incorporating different input parameters is examined. Then, the assessment of fuel consumption savings due to the design measures is performed using the ANN models which have been trained on separate data before and after the adoption of measures.
{"title":"Examining the performance of retrofit measures in real ship operation using data-driven models","authors":"G. Nikolaidis, N. Themelis","doi":"10.1080/09377255.2022.2109327","DOIUrl":"https://doi.org/10.1080/09377255.2022.2109327","url":null,"abstract":"ABSTRACT The quantification of the effect of ship design measures on its energy efficiency during real operation and using data-driven models is presented. Data collected from automated logging and meteorological service provider, received before and after the ship retrofit are utilized. Initially, a data preparation analysis is carried out and the input variables for the prediction of the main engine’s fuel oil consumption are selected. Afterwards, artificial neural networks (ANNs) design techniques are investigated utilizing modern machine learning methods. The generalization competence of a model is assessed based on its efficiency to cope with data that were not used in its training. Furthermore, the accuracy achieved by models incorporating different input parameters is examined. Then, the assessment of fuel consumption savings due to the design measures is performed using the ANN models which have been trained on separate data before and after the adoption of measures.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46499728","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 : 2022-08-01DOI: 10.1080/09377255.2022.2106218
R. Hamann, P. Sames
ABSTRACT Historical information is the key input for risk analysis with respect to developing the risk model as well as in the risk management process, i.e. identification of effective risk mitigating measures. Casualty databases are today still the primary source of this information on accidents and incidents. Accident investigation reports provide more detailed information on the accident scenario and facilitating improved risk analysis. Casualty information by IMO GISIS, IHS Markit and LMIU for the period 1990–2020 and containerships of more than 999 GT had been re-analyzed and information categorized for allowing statistical analysis of causes. A taxonomy had been developed for the consistent categorization of information and used to present accident causes in a more structured way. Appropriate statistics regarding the main causes for major types considering collision, contact, grounding, fire, explosion and failure of machinery equipment are presented in this paper. Historical trends and quantitative casualty characteristics are reported.
{"title":"Updated and expanded casualty analysis of container vessels","authors":"R. Hamann, P. Sames","doi":"10.1080/09377255.2022.2106218","DOIUrl":"https://doi.org/10.1080/09377255.2022.2106218","url":null,"abstract":"ABSTRACT Historical information is the key input for risk analysis with respect to developing the risk model as well as in the risk management process, i.e. identification of effective risk mitigating measures. Casualty databases are today still the primary source of this information on accidents and incidents. Accident investigation reports provide more detailed information on the accident scenario and facilitating improved risk analysis. Casualty information by IMO GISIS, IHS Markit and LMIU for the period 1990–2020 and containerships of more than 999 GT had been re-analyzed and information categorized for allowing statistical analysis of causes. A taxonomy had been developed for the consistent categorization of information and used to present accident causes in a more structured way. Appropriate statistics regarding the main causes for major types considering collision, contact, grounding, fire, explosion and failure of machinery equipment are presented in this paper. Historical trends and quantitative casualty characteristics are reported.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42875259","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 : 2022-07-08DOI: 10.1080/09377255.2022.2096951
Zakarya Laffane, Fethi Saidi, A. Souto-Iglesias, Y. Boualia, B. Hamoudi
ABSTRACT This paper presents an experimental study of a passive version of the Water-jet vortex generator to reduce the drag force over a NACA 661-012 hydrofoil. The passive blowing used the overpressure zone at the leading edge of the hydrofoil’s lower surface as a source of water jets that create jets on the upper surface of the hydrofoil using the blowing tubes. The experimental tests were carried out in the towing tank in Universidad Politécnica de Madrid (UPM) with a hydrofoil model with a 250-mm long chord at Reynolds numbers of (1.4 105 < Re < 2.8 105). It was found that the passive water-jet vortex-generator reduces the drag force with a slight lift decrease.
摘要:本文介绍了一种用于减小NACA 661-012型水翼阻力的被动型射流涡发生器的实验研究。被动吹风利用水翼下表面前缘的超压区作为水射流的来源，利用吹风管在水翼的上表面产生射流。采用250 mm长弦水翼模型，在(1.4 105 < Re < 2.8 105)雷诺数条件下，在马德里大学(UPM)的拖曳槽中进行了实验试验。结果表明，被动水射流涡发生器在减小阻力的同时，升力略有下降。
{"title":"Experimental study on the performance of a hydrofoil using passive water-jet vortex generators","authors":"Zakarya Laffane, Fethi Saidi, A. Souto-Iglesias, Y. Boualia, B. Hamoudi","doi":"10.1080/09377255.2022.2096951","DOIUrl":"https://doi.org/10.1080/09377255.2022.2096951","url":null,"abstract":"ABSTRACT This paper presents an experimental study of a passive version of the Water-jet vortex generator to reduce the drag force over a NACA 661-012 hydrofoil. The passive blowing used the overpressure zone at the leading edge of the hydrofoil’s lower surface as a source of water jets that create jets on the upper surface of the hydrofoil using the blowing tubes. The experimental tests were carried out in the towing tank in Universidad Politécnica de Madrid (UPM) with a hydrofoil model with a 250-mm long chord at Reynolds numbers of (1.4 105 < Re < 2.8 105). It was found that the passive water-jet vortex-generator reduces the drag force with a slight lift decrease.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45462484","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 : 2022-03-25DOI: 10.1080/09377255.2022.2054759
Gabriele Bigini, M. Jacoby, Annemarie Steenbergen, Luigi Francesco Minerva, D. Villa, G. Vernengo
ABSTRACT This paper presents the results of the hydrodynamic optimization of a large yacht concept design that is meant to be used as a reference for future buildings. The optimization framework is used to improve the calm water resistance performance of a generic baseline design while satisfying a set of geometrical constraints. The shape of the hull is modified according to a geometrical interpolation approach where two shapes are combined to obtain a third design. The search towards the optimum is driven by a global convergence, multi-objective, genetic algorithm where the resistance of each candidate is evaluated by a Boundary Element Method. The final optimal design is then verified by means of a high-fidelity Reynolds Averaged Navier–Stokes technique, preliminary validated against available experimental data. The obtained results show the strong influence of the stern shape of the hull on the final resistance performance, highlighting the effects of the pressure recovery due to a so-called S-shape bottom. The bow shape is modified consistently to fulfil the geometric constraints and to further improve the resistance performance by inducing a positive interference effect on the generated wave pattern.
{"title":"Large yacht resistance reduction by hydrodynamic multi-objective shape optimization","authors":"Gabriele Bigini, M. Jacoby, Annemarie Steenbergen, Luigi Francesco Minerva, D. Villa, G. Vernengo","doi":"10.1080/09377255.2022.2054759","DOIUrl":"https://doi.org/10.1080/09377255.2022.2054759","url":null,"abstract":"ABSTRACT This paper presents the results of the hydrodynamic optimization of a large yacht concept design that is meant to be used as a reference for future buildings. The optimization framework is used to improve the calm water resistance performance of a generic baseline design while satisfying a set of geometrical constraints. The shape of the hull is modified according to a geometrical interpolation approach where two shapes are combined to obtain a third design. The search towards the optimum is driven by a global convergence, multi-objective, genetic algorithm where the resistance of each candidate is evaluated by a Boundary Element Method. The final optimal design is then verified by means of a high-fidelity Reynolds Averaged Navier–Stokes technique, preliminary validated against available experimental data. The obtained results show the strong influence of the stern shape of the hull on the final resistance performance, highlighting the effects of the pressure recovery due to a so-called S-shape bottom. The bow shape is modified consistently to fulfil the geometric constraints and to further improve the resistance performance by inducing a positive interference effect on the generated wave pattern.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47983005","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 : 2022-03-22DOI: 10.1080/09377255.2022.2049967
Martin Bergström, T. Browne, S. Ehlers, I. Helle, H. Herrnring, Faisal Khan, J. Kubiczek, P. Kujala, M. Kõrgesaar, B. Leira, T. Parviainen, Arttu Polojärvi, M. Suominen, R. Taylor, J. Tuhkuri, J. Vanhatalo, B. Veitch
ABSTRACT While society benefits from Arctic shipping, it is necessary to recognize that ship operations in Arctic waters pose significant risks to people, the environment, and property. To support the management of those risks, this article presents a comprehensive approach addressing both short-term operational risks, as well as risks related to long-term extreme ice loads. For the management of short-term operational risks, an extended version of the Polar Operational Limit Assessment Risk Indexing System (POLARIS) considering the magnitude of the consequences of potential adverse events is proposed. For the management of risks related to long-term extreme ice loads, guidelines are provided for using existing analytical, numerical, and semi-empirical methods. In addition, to support the design of ice class ship structures, the article proposes a novel approach that can be used in the conceptual design phase for the determination of preliminary scantlings for primary hull structural members.
{"title":"A comprehensive approach to scenario-based risk management for Arctic waters","authors":"Martin Bergström, T. Browne, S. Ehlers, I. Helle, H. Herrnring, Faisal Khan, J. Kubiczek, P. Kujala, M. Kõrgesaar, B. Leira, T. Parviainen, Arttu Polojärvi, M. Suominen, R. Taylor, J. Tuhkuri, J. Vanhatalo, B. Veitch","doi":"10.1080/09377255.2022.2049967","DOIUrl":"https://doi.org/10.1080/09377255.2022.2049967","url":null,"abstract":"ABSTRACT While society benefits from Arctic shipping, it is necessary to recognize that ship operations in Arctic waters pose significant risks to people, the environment, and property. To support the management of those risks, this article presents a comprehensive approach addressing both short-term operational risks, as well as risks related to long-term extreme ice loads. For the management of short-term operational risks, an extended version of the Polar Operational Limit Assessment Risk Indexing System (POLARIS) considering the magnitude of the consequences of potential adverse events is proposed. For the management of risks related to long-term extreme ice loads, guidelines are provided for using existing analytical, numerical, and semi-empirical methods. In addition, to support the design of ice class ship structures, the article proposes a novel approach that can be used in the conceptual design phase for the determination of preliminary scantlings for primary hull structural members.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43479936","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 : 2022-01-25DOI: 10.1080/09377255.2022.2029307
F. A. Nugroho, H. Herrnring, S. Ehlers
ABSTRACT A lower pitting severity produces a shallower corrosion pit shape on a corroded ballast tank. Pit distributions of corroded specimens have a probability model for the non-Gaussian surface. Therefore, the present work focuses on the numerical study of stress distribution within the corrosion pit area, while considering different corrosion pit geometries. Accordingly, 45 dog bone-shaped finite element models with a single corrosion pit are investigated. The geometrical parameters of the corrosion pit are analyzed with quantitative correlations at different sizes, shapes, and different levels of enlargement. Additionally, a corrosion pit alteration scenario is proposed, with a narrow deep, hemispherical, and final shallow wide form. Results show that the stress concentration factor remains relatively constant at the pit edge and increases toward the pit bottom. Furthermore, stress declines on the pit bottom and shallower corrosion pit form, which conforms to the polynomial trendline.
{"title":"Influence of corrosion pit geometry on stress distribution within a single artificial pit","authors":"F. A. Nugroho, H. Herrnring, S. Ehlers","doi":"10.1080/09377255.2022.2029307","DOIUrl":"https://doi.org/10.1080/09377255.2022.2029307","url":null,"abstract":"ABSTRACT A lower pitting severity produces a shallower corrosion pit shape on a corroded ballast tank. Pit distributions of corroded specimens have a probability model for the non-Gaussian surface. Therefore, the present work focuses on the numerical study of stress distribution within the corrosion pit area, while considering different corrosion pit geometries. Accordingly, 45 dog bone-shaped finite element models with a single corrosion pit are investigated. The geometrical parameters of the corrosion pit are analyzed with quantitative correlations at different sizes, shapes, and different levels of enlargement. Additionally, a corrosion pit alteration scenario is proposed, with a narrow deep, hemispherical, and final shallow wide form. Results show that the stress concentration factor remains relatively constant at the pit edge and increases toward the pit bottom. Furthermore, stress declines on the pit bottom and shallower corrosion pit form, which conforms to the polynomial trendline.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46319142","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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