Pub Date : 2024-08-02DOI: 10.1177/14750902241265883
Jian Wang, Jun Wang, Xiaofeng Liang, Yafeng Liu, Hong Yi
The complexity of hull-structure calculation and the diversity of random distributions of uncertainty factors necessitate structural reliability analysis methods that are cost-effective, efficient and adaptable to multiple distributions. This paper proposes a novel reliability analysis method of the hull structure based on Generalized Polynomial Chaos (GPC). GPC surrogate models for performance functions are developed for two typical cases with different distributions within the hull structure. The variations in mean, standard deviation, reliability index and failure probability with respect to GPC expansion order and sample size are analysed and compared with traditional methods, including Monte Carlo (MC) and the First-Order Reliability Method (FORM). The results indicate that the GPC-based method is effective for handling random variables of various distributions in hull structures. Moreover, the proposed method demonstrates superior convergence and accuracy compared to MC and FORM. By circumventing the need for extensive sample calculations for real structural models, the GPC-based method enhances computational efficiency. The feasibility and efficiency of the GPC-based structural reliability analysis method are validated, offering a promising new approach for assessing the reliability of hull structures.
船体结构计算的复杂性和不确定性因素随机分布的多样性要求结构可靠性分析方法具有成本效益、效率高和适应多种分布的特点。本文提出了一种基于广义多项式混沌（GPC）的新型船体结构可靠性分析方法。针对船体结构内部不同分布的两种典型情况，建立了性能函数的 GPC 代用模型。分析了平均值、标准偏差、可靠性指数和失效概率随 GPC 扩展阶数和样本量的变化，并将其与蒙特卡罗法（MC）和一阶可靠性法（FORM）等传统方法进行了比较。结果表明，基于 GPC 的方法能有效处理船体结构中各种分布的随机变量。此外，与 MC 和 FORM 相比，所提出的方法具有更高的收敛性和准确性。通过避免对实际结构模型进行大量样本计算，基于 GPC 的方法提高了计算效率。基于 GPC 的结构可靠性分析方法的可行性和效率得到了验证，为评估船体结构的可靠性提供了一种前景广阔的新方法。
{"title":"Reliability analysis method of the hull structure based on generalized polynomial chaos","authors":"Jian Wang, Jun Wang, Xiaofeng Liang, Yafeng Liu, Hong Yi","doi":"10.1177/14750902241265883","DOIUrl":"https://doi.org/10.1177/14750902241265883","url":null,"abstract":"The complexity of hull-structure calculation and the diversity of random distributions of uncertainty factors necessitate structural reliability analysis methods that are cost-effective, efficient and adaptable to multiple distributions. This paper proposes a novel reliability analysis method of the hull structure based on Generalized Polynomial Chaos (GPC). GPC surrogate models for performance functions are developed for two typical cases with different distributions within the hull structure. The variations in mean, standard deviation, reliability index and failure probability with respect to GPC expansion order and sample size are analysed and compared with traditional methods, including Monte Carlo (MC) and the First-Order Reliability Method (FORM). The results indicate that the GPC-based method is effective for handling random variables of various distributions in hull structures. Moreover, the proposed method demonstrates superior convergence and accuracy compared to MC and FORM. By circumventing the need for extensive sample calculations for real structural models, the GPC-based method enhances computational efficiency. The feasibility and efficiency of the GPC-based structural reliability analysis method are validated, offering a promising new approach for assessing the reliability of hull structures.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"187 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141886349","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 : 2024-08-02DOI: 10.1177/14750902241266127
Shujiang Wang, Jijun Gu, Leilei Chen, Jichuan Jia, Jun Huang, Lei Gao
The buoyancy module installed on the steel lazy-wave riser makes the riser locally S-shaped, which weakens the motion transmission from the top to the bottom but makes the pipe-soil interaction more susceptible to the buoyancy configuration. In this study, a two-dimensional planar static numerical model considering the riser global motion coupled with the nonlinear seabed interaction is developed. The planar co-rotating beam element is established based on the co-rotating coordinate method, the vertical soil resistance is simulated by the semi-empirical pipe-soil interaction model. And the global displacement of the riser and the soil resistance of the seabed are coupled in the co-rotational framework by the principle of minimum potential energy. Finally, the parametric effects of buoyancy configurations and riser structural characteristics are analysed. The results show that the established numerical model is suitable for solving the vertical pipe-soil interaction between riser and nonlinear seabed. Compared with SCR, the maximum embedment depth of SLWR in the TDZ is reduced by 23.5%, and the maximum vertical soil resistance is reduced by 8.26%. In the two buoyancy configuration adjustment methods, increasing the buoyancy section length obviously changes the shape of SLWR, resulting in significant changes in the embedment depth and vertical soil resistance.
{"title":"Numerical study on the effect of SLWR buoyancy configuration on pipe-soil interaction based on co-rotational method","authors":"Shujiang Wang, Jijun Gu, Leilei Chen, Jichuan Jia, Jun Huang, Lei Gao","doi":"10.1177/14750902241266127","DOIUrl":"https://doi.org/10.1177/14750902241266127","url":null,"abstract":"The buoyancy module installed on the steel lazy-wave riser makes the riser locally S-shaped, which weakens the motion transmission from the top to the bottom but makes the pipe-soil interaction more susceptible to the buoyancy configuration. In this study, a two-dimensional planar static numerical model considering the riser global motion coupled with the nonlinear seabed interaction is developed. The planar co-rotating beam element is established based on the co-rotating coordinate method, the vertical soil resistance is simulated by the semi-empirical pipe-soil interaction model. And the global displacement of the riser and the soil resistance of the seabed are coupled in the co-rotational framework by the principle of minimum potential energy. Finally, the parametric effects of buoyancy configurations and riser structural characteristics are analysed. The results show that the established numerical model is suitable for solving the vertical pipe-soil interaction between riser and nonlinear seabed. Compared with SCR, the maximum embedment depth of SLWR in the TDZ is reduced by 23.5%, and the maximum vertical soil resistance is reduced by 8.26%. In the two buoyancy configuration adjustment methods, increasing the buoyancy section length obviously changes the shape of SLWR, resulting in significant changes in the embedment depth and vertical soil resistance.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"55 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141886351","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 : 2024-07-31DOI: 10.1177/14750902241266299
Hugan Zhang, Xianku Zhang, Shihang Gao, Daocheng Ma
To address the challenges posed by unmodeled dynamics, lateral drift, external disturbances, and the difficulty in measuring velocities in underactuated surface vessels (USVs) motion systems, an active disturbance rejection control (ADRC) with two linear extended state observers (LESO) is proposed for USV path following. Firstly, we employ the Backstepping technique to create a virtual heading angle while estimating lateral drift and unmodeled dynamics using LESO. Subsequently, the ADRC algorithm is employed to control the heading angle. Since measuring the velocities of USV is challenging, velocity observers are introduce to estimate surge and sway velocities. Finally, we utilize the MMG model with high precision to track straight-line and curved paths, respectively. Simulation results validate that our developed controller accurately follows the reference path even in the presence of disturbances, affirming the effectiveness of our proposed control strategy.
{"title":"Path following of underactuated surface vessels based active disturbance rejection control considering lateral drift","authors":"Hugan Zhang, Xianku Zhang, Shihang Gao, Daocheng Ma","doi":"10.1177/14750902241266299","DOIUrl":"https://doi.org/10.1177/14750902241266299","url":null,"abstract":"To address the challenges posed by unmodeled dynamics, lateral drift, external disturbances, and the difficulty in measuring velocities in underactuated surface vessels (USVs) motion systems, an active disturbance rejection control (ADRC) with two linear extended state observers (LESO) is proposed for USV path following. Firstly, we employ the Backstepping technique to create a virtual heading angle while estimating lateral drift and unmodeled dynamics using LESO. Subsequently, the ADRC algorithm is employed to control the heading angle. Since measuring the velocities of USV is challenging, velocity observers are introduce to estimate surge and sway velocities. Finally, we utilize the MMG model with high precision to track straight-line and curved paths, respectively. Simulation results validate that our developed controller accurately follows the reference path even in the presence of disturbances, affirming the effectiveness of our proposed control strategy.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"12 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868842","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}
Port integration can enhance operational efficiency and service level in response to heightened competition among container ports. Nevertheless, container ports are still considered independent systems separately in formulating scheduling plans. This research explores a new multi-port berth allocation problem (MPBAP) with continuous berth layout considering the mutual influence between ports. The MPBAP is compared with the single port berth allocation, and effects of different numbers of vessels continuously berthing at all ports on a single route on the MPBAP are discussed through vessel operation rate. The problem is formulated by a mixed integer programming model by minimising the total port stay time of all vessels. The quay is highly discretised and a GA coupled with parallel computing is applied to accelerate the search for the optimal model solution. A case study is conducted on two adjacent container ports located along the Yangtze River. Results show that multi-port coordinated scheduling is efficiency and the total port stay time of all vessels reduces by an average of 2.63% under the MPBAP. With more than four vessels berthing continuously at two ports on a single route, the MPBAP shows a higher vessel operation rate and the rate gap between the two models exceeds 2%. The approach suggested in this study can enhance the port system’s efficiency and provide a new idea for coordinated scheduling in other port groups.
{"title":"A new model for multi-port berth allocation problem based on an improved genetic algorithm","authors":"Shuang Tang, Sudong Xu, Kai Yin, Nini Zhang, Liuyan Mao, Xiangtong Chen","doi":"10.1177/14750902241267039","DOIUrl":"https://doi.org/10.1177/14750902241267039","url":null,"abstract":"Port integration can enhance operational efficiency and service level in response to heightened competition among container ports. Nevertheless, container ports are still considered independent systems separately in formulating scheduling plans. This research explores a new multi-port berth allocation problem (MPBAP) with continuous berth layout considering the mutual influence between ports. The MPBAP is compared with the single port berth allocation, and effects of different numbers of vessels continuously berthing at all ports on a single route on the MPBAP are discussed through vessel operation rate. The problem is formulated by a mixed integer programming model by minimising the total port stay time of all vessels. The quay is highly discretised and a GA coupled with parallel computing is applied to accelerate the search for the optimal model solution. A case study is conducted on two adjacent container ports located along the Yangtze River. Results show that multi-port coordinated scheduling is efficiency and the total port stay time of all vessels reduces by an average of 2.63% under the MPBAP. With more than four vessels berthing continuously at two ports on a single route, the MPBAP shows a higher vessel operation rate and the rate gap between the two models exceeds 2%. The approach suggested in this study can enhance the port system’s efficiency and provide a new idea for coordinated scheduling in other port groups.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"51 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868638","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 : 2024-07-29DOI: 10.1177/14750902241265173
Victor Bolbot, La Xiang, Päivi Brunou, Mikko Kiviharju, Yu Ding, Osiris Valdez Banda
Increased connectivity renders the ships more cost-effective but also vulnerable to cyberattacks. Since ships are assets of significant value and importance, they constitute a lucrative object for cyber-attacks. The power and propulsion functions are among the most safety critical and essential for ship operations. Simultaneously, the use of Dual-Fuel (DF) engines for power generation and propulsion has become very popular in the recent years. The aim of this research is the risk identification and analysis of potential cybersecurity attack scenarios in a DF engine on inland waterways ship. For this purpose, we employ an adapted version of Failure Modes, Vulnerabilities and Effects Analysis (FMVEA). In our approach we demonstrate how the implementation of FMVEA can be interconnected with the existing assurance processes for maritime engines and novel developments in the field of risk theory. We also provide insights in the riskiest cybersecurity attacks on DF engine and how to reduce their risks.
{"title":"Cybersecurity risk assessment of a marine dual-fuel engine on inland waterways ship","authors":"Victor Bolbot, La Xiang, Päivi Brunou, Mikko Kiviharju, Yu Ding, Osiris Valdez Banda","doi":"10.1177/14750902241265173","DOIUrl":"https://doi.org/10.1177/14750902241265173","url":null,"abstract":"Increased connectivity renders the ships more cost-effective but also vulnerable to cyberattacks. Since ships are assets of significant value and importance, they constitute a lucrative object for cyber-attacks. The power and propulsion functions are among the most safety critical and essential for ship operations. Simultaneously, the use of Dual-Fuel (DF) engines for power generation and propulsion has become very popular in the recent years. The aim of this research is the risk identification and analysis of potential cybersecurity attack scenarios in a DF engine on inland waterways ship. For this purpose, we employ an adapted version of Failure Modes, Vulnerabilities and Effects Analysis (FMVEA). In our approach we demonstrate how the implementation of FMVEA can be interconnected with the existing assurance processes for maritime engines and novel developments in the field of risk theory. We also provide insights in the riskiest cybersecurity attacks on DF engine and how to reduce their risks.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"22 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868843","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 : 2024-07-29DOI: 10.1177/14750902241266118
Dingyu Cui, Tianchi Zhang, Mingjun Zhang, Xing Liu
Fault feature extraction, feature fusion and severity identification approaches for autonomous underwater vehicles with weak thruster faults are studied in the article. The traditional method uses the modified Bayes algorithm for fault feature extraction from different signals, then the fault features are fused through the Dempster-Shafer evidence theory, and finally, the severities of the faults are obtained by the grey relation analysis method through the fused features. But for weak thruster faults, in the stage of feature extraction, it exists the problem that the ratios of fault eigenvalues to noise eigenvalues of the extracted features are low. In the stages of feature fusion and severity identification, it exists the problem that the errors of the identification results obtained from the fused fault features are not satisfactory. Aiming at the above problems, the smoothed pseudo Wigner-Ville distribution together with the modified Bayes method is presented for feature extraction for weak faults. The feature-level fusion together with the decision-level fusion method is presented for feature fusion and severity identification for weak faults. The experimental prototype pool experiments verify the effectiveness of the approaches presented in this article.
{"title":"Fault feature extraction, feature fusion, and severity identification approaches for AUVs with weak thruster faults","authors":"Dingyu Cui, Tianchi Zhang, Mingjun Zhang, Xing Liu","doi":"10.1177/14750902241266118","DOIUrl":"https://doi.org/10.1177/14750902241266118","url":null,"abstract":"Fault feature extraction, feature fusion and severity identification approaches for autonomous underwater vehicles with weak thruster faults are studied in the article. The traditional method uses the modified Bayes algorithm for fault feature extraction from different signals, then the fault features are fused through the Dempster-Shafer evidence theory, and finally, the severities of the faults are obtained by the grey relation analysis method through the fused features. But for weak thruster faults, in the stage of feature extraction, it exists the problem that the ratios of fault eigenvalues to noise eigenvalues of the extracted features are low. In the stages of feature fusion and severity identification, it exists the problem that the errors of the identification results obtained from the fused fault features are not satisfactory. Aiming at the above problems, the smoothed pseudo Wigner-Ville distribution together with the modified Bayes method is presented for feature extraction for weak faults. The feature-level fusion together with the decision-level fusion method is presented for feature fusion and severity identification for weak faults. The experimental prototype pool experiments verify the effectiveness of the approaches presented in this article.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"40 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868680","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 : 2024-06-20DOI: 10.1177/14750902241260104
Dewen Zhu, Zhiyu Zhu
In order to improve the stability of the underwater vehicle, the output fault-tolerant control method of the underwater vehicle based on adaptive sliding mode control is designed on the basis of setting multiple constraints. After the dynamic analysis of the underwater vehicle and its thruster, the output dimension constraint, input amplitude constraint, and state amplitude constraint were set. Based on these three constraints, the recursive cerebellar neural network is used to identify the time-varying and nonlinear unknown faults in the underwater vehicle online, and a deep convolution neural network is used to detect the known faults of the underwater vehicle. The error correction output code is then combined with a support vector machine to classify the detected faults. Finally, the output fault-tolerant control of an underwater vehicle is realized based on adaptive sliding mode control. The experiment shows that after the application of this method, because the recursive cerebellar neural network and the deep convolution neural network can estimate the size of the fault information in time, the sliding mode fault-tolerant controller can readjust the output of the controller according to the result of the fault identification to offset the effect of the fault on the robot, so that the robot can continue to maintain the original stable operation state. Even if the thruster has faults, this method can adjust the output of the thruster in time and reconstruct and recover the total control output, so that the actual output thrust is very close to the expected value, to achieve fault-tolerant control of the underwater vehicle output.
{"title":"Output fault-tolerant control of underwater vehicle based on adaptive sliding mode control under multiple constraints","authors":"Dewen Zhu, Zhiyu Zhu","doi":"10.1177/14750902241260104","DOIUrl":"https://doi.org/10.1177/14750902241260104","url":null,"abstract":"In order to improve the stability of the underwater vehicle, the output fault-tolerant control method of the underwater vehicle based on adaptive sliding mode control is designed on the basis of setting multiple constraints. After the dynamic analysis of the underwater vehicle and its thruster, the output dimension constraint, input amplitude constraint, and state amplitude constraint were set. Based on these three constraints, the recursive cerebellar neural network is used to identify the time-varying and nonlinear unknown faults in the underwater vehicle online, and a deep convolution neural network is used to detect the known faults of the underwater vehicle. The error correction output code is then combined with a support vector machine to classify the detected faults. Finally, the output fault-tolerant control of an underwater vehicle is realized based on adaptive sliding mode control. The experiment shows that after the application of this method, because the recursive cerebellar neural network and the deep convolution neural network can estimate the size of the fault information in time, the sliding mode fault-tolerant controller can readjust the output of the controller according to the result of the fault identification to offset the effect of the fault on the robot, so that the robot can continue to maintain the original stable operation state. Even if the thruster has faults, this method can adjust the output of the thruster in time and reconstruct and recover the total control output, so that the actual output thrust is very close to the expected value, to achieve fault-tolerant control of the underwater vehicle output.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"33 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509584","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 : 2024-06-20DOI: 10.1177/14750902241257563
William Kuplis, Jason Ali-Lavroff, Abbas Dashtimanesh, Chun-Yu Lau
A 150 m electric wave-piercing catamaran concept from Incat Tasmania is analysed using CFD to explore the hydrodynamic impact of operating speed and hull separation on vessel performance and CO2 emissions reduction. Over the investigated speed range of 0.2 < Fr < 0.4, interference factors are evaluated for four demihull separation ratios ( s/ L) and two demihull slenderness ratios ( L/∇1/3). The implications on total life-cycle CO2 emissions are presented as a function of total vessel resistance, and the significance discussed. A separation ratio of s/ L = 0.220 provides the lowest overall resistance, however other configurations provide superior results for specific Froude numbers. The concept of transportation capacity is introduced and used to demonstrate the advantage of slower speeds for the electric powertrain through identification of a critical Froude number Fr = 0.35, above which transportation capacity is reduced as a consequence of the low energy density of Nickel Manganese Cobalt (NMC) batteries. A comparison is also made between the electric and equivalent LNG and diesel powertrains to demonstrate the effect of fuel carbon intensities on standardised vessel CO2 emissions. Through analysis of the transportation capacity and emissions reduction of the electric vessel, a speed of Fr = 0.28 is proposed as a compromise between the two, with further power and emissions reductions achievable near this speed by adopting a narrower hull separation ratio of s/ L = 0.151.
{"title":"Investigation of CO2 emissions reduction for a 150 m electric catamaran by CFD analysis of various hull configurations","authors":"William Kuplis, Jason Ali-Lavroff, Abbas Dashtimanesh, Chun-Yu Lau","doi":"10.1177/14750902241257563","DOIUrl":"https://doi.org/10.1177/14750902241257563","url":null,"abstract":"A 150 m electric wave-piercing catamaran concept from Incat Tasmania is analysed using CFD to explore the hydrodynamic impact of operating speed and hull separation on vessel performance and CO<jats:sub>2</jats:sub> emissions reduction. Over the investigated speed range of 0.2 < Fr < 0.4, interference factors are evaluated for four demihull separation ratios ( s/ L) and two demihull slenderness ratios ( L/∇<jats:sup>1/3</jats:sup>). The implications on total life-cycle CO<jats:sub>2</jats:sub> emissions are presented as a function of total vessel resistance, and the significance discussed. A separation ratio of s/ L = 0.220 provides the lowest overall resistance, however other configurations provide superior results for specific Froude numbers. The concept of transportation capacity is introduced and used to demonstrate the advantage of slower speeds for the electric powertrain through identification of a critical Froude number Fr = 0.35, above which transportation capacity is reduced as a consequence of the low energy density of Nickel Manganese Cobalt (NMC) batteries. A comparison is also made between the electric and equivalent LNG and diesel powertrains to demonstrate the effect of fuel carbon intensities on standardised vessel CO<jats:sub>2</jats:sub> emissions. Through analysis of the transportation capacity and emissions reduction of the electric vessel, a speed of Fr = 0.28 is proposed as a compromise between the two, with further power and emissions reductions achievable near this speed by adopting a narrower hull separation ratio of s/ L = 0.151.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"5 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509587","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 : 2024-05-29DOI: 10.1177/14750902241253319
Majid Rahimie Esfidan, Ahmad Rahbar Ranji
To have a proper maintenance policy for ships and offshore structures, it is necessary to predict corrosion wastage accurately. It is the main aim of the present work to propose corrosion models for plates in ship structures. In total 66,480 data were collected from thickness measurements carried out by different classification societies. The data were sorted out based on the position of the plate, the age of the ship, the country where the ship was built, and the type of ship. Using regression analysis, some models were proposed as a function of the ship’s age and position of plate. Based on this study, the proposed models are checked against existing corrosion models in the literature and it is found that other corrosion models underestimate the corrosion rate in the inner bottom plates, and deck plates. However, they overestimate the amount of corrosion in the side plates of ships. The existing corrosion models are justified for the prediction of corrosion wastage in hatch-coaming plates. For corrosion of outer bottom plates, the existing corrosion models are applicable for ships under 20 years old. They overestimate corrosion wastage for ships older than 20 years. Also, existing corrosion models overestimate corrosion wastage of plates at the side structure of ships above the water line at the early age of ships and underestimate in older ships.
{"title":"Corrosion models for steel plates in ship structure based on statistical data","authors":"Majid Rahimie Esfidan, Ahmad Rahbar Ranji","doi":"10.1177/14750902241253319","DOIUrl":"https://doi.org/10.1177/14750902241253319","url":null,"abstract":"To have a proper maintenance policy for ships and offshore structures, it is necessary to predict corrosion wastage accurately. It is the main aim of the present work to propose corrosion models for plates in ship structures. In total 66,480 data were collected from thickness measurements carried out by different classification societies. The data were sorted out based on the position of the plate, the age of the ship, the country where the ship was built, and the type of ship. Using regression analysis, some models were proposed as a function of the ship’s age and position of plate. Based on this study, the proposed models are checked against existing corrosion models in the literature and it is found that other corrosion models underestimate the corrosion rate in the inner bottom plates, and deck plates. However, they overestimate the amount of corrosion in the side plates of ships. The existing corrosion models are justified for the prediction of corrosion wastage in hatch-coaming plates. For corrosion of outer bottom plates, the existing corrosion models are applicable for ships under 20 years old. They overestimate corrosion wastage for ships older than 20 years. Also, existing corrosion models overestimate corrosion wastage of plates at the side structure of ships above the water line at the early age of ships and underestimate in older ships.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"2 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141192174","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 : 2024-04-16DOI: 10.1177/14750902241245539
Zhiqiang Han, Yang Liu, Xiaohong Wu, Daekyun Oh, Jaewon Jang
The design and construction characteristics, including glass fibre weight fraction ( Gc), number of single-ply layers, fabric combination, and fabrication quality, of glass fibre reinforcement polymer (GFRP) hull plates affect ultrasound propagation characteristics, such as ultrasonic velocity and attenuation, thereby influencing the accuracy of ultrasonic non-destructive test results. Therefore, this study is to propose a method to decrease the ultrasonic test errors of GFRP hull plate by using statistical method. The GFRP specimens with Gc of approximately 30–50 wt%, thicknesses of approximately 5–20 mm, and different fabric combinations were prepared using the hand lay-up method, considering the general design–construction characteristics. Further, an ultrasonic velocity decision method for ultrasonic inspection was proposed considering the GFRP hull design-construction characteristics, such as Gc and number of single-ply layers of hull plate by multiple linear regression method. The results show that the proposed method can reduce the thickness measurement error from approximately 20%–30% to 1%–2%, compared to an existing ultrasonic inspection method, only considering the Gc effect on ultrasonic velocity, which indicates that the proposed test method is suitable for practical applications.
{"title":"Ultrasonic non-destructive inspection method for glass fibre reinforcement polymer (GFRP) hull plates considering design and construction characteristics","authors":"Zhiqiang Han, Yang Liu, Xiaohong Wu, Daekyun Oh, Jaewon Jang","doi":"10.1177/14750902241245539","DOIUrl":"https://doi.org/10.1177/14750902241245539","url":null,"abstract":"The design and construction characteristics, including glass fibre weight fraction ( Gc), number of single-ply layers, fabric combination, and fabrication quality, of glass fibre reinforcement polymer (GFRP) hull plates affect ultrasound propagation characteristics, such as ultrasonic velocity and attenuation, thereby influencing the accuracy of ultrasonic non-destructive test results. Therefore, this study is to propose a method to decrease the ultrasonic test errors of GFRP hull plate by using statistical method. The GFRP specimens with Gc of approximately 30–50 wt%, thicknesses of approximately 5–20 mm, and different fabric combinations were prepared using the hand lay-up method, considering the general design–construction characteristics. Further, an ultrasonic velocity decision method for ultrasonic inspection was proposed considering the GFRP hull design-construction characteristics, such as Gc and number of single-ply layers of hull plate by multiple linear regression method. The results show that the proposed method can reduce the thickness measurement error from approximately 20%–30% to 1%–2%, compared to an existing ultrasonic inspection method, only considering the Gc effect on ultrasonic velocity, which indicates that the proposed test method is suitable for practical applications.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615898","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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