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Keywords = hull girder

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28 pages, 6413 KiB  
Article
Scaling the Dynamic Buckling Behavior of a Box Girder Based on the Finite Similitude Approach
by Chongxi Xu, Zhuo Wang, Xiangshao Kong, Hu Zhou, Cheng Zheng and Weiguo Wu
J. Mar. Sci. Eng. 2025, 13(8), 1496; https://doi.org/10.3390/jmse13081496 - 4 Aug 2025
Viewed by 110
Abstract
In the design of small-scale test models for hull structures, the directional dimensional analysis method is commonly employed. However, conventional dimensional analysis based on elasticity theory may be insufficient to capture the nonlinear behaviors of structural materials under dynamic loading, which restricts its [...] Read more.
In the design of small-scale test models for hull structures, the directional dimensional analysis method is commonly employed. However, conventional dimensional analysis based on elasticity theory may be insufficient to capture the nonlinear behaviors of structural materials under dynamic loading, which restricts its applicability in ultimate strength tests for small-scale hull structure models. This paper presents a scaling method grounded in the theory of finite similitude. Based on the finite similitude theory, this paper deduces similarity scaling criteria applicable to the static and dynamic responses of box girders and designs a series of trial models of box girders. The scaling criteria are verified and analyzed through numerical tests conducted under static and dynamic loads. On the basis of the numerical test results of dynamic responses, the dynamic response similarity criteria considering the similarity relationship of material constitutive parameters are modified and verified. By applying the static response scaling criteria in this paper to select appropriate materials, the prediction deviation of the box girder trial models under static loads is less than 2%. With the modified dynamic response scaling criteria proposed in this paper, the prediction deviations of each trial model under dynamic loads are less than 2% and 7%. A comprehensive analysis of material parameters was conducted to examine their impact on the nonlinear similarities observed in the processes. To validate the ultimate strength and nonlinear response scaling criterion based on the finite similitude approach, numerical experiments were performed to assess the ultimate strength and dynamic buckling response characteristics of the box girder across various scaling ratios and material parameters. The analysis demonstrated that the ultimate strength scaling criterion and the nonlinear response scaling criterion derived from the finite similitude approach effectively captured material nonlinearity. The results from the small-scale model provided accurate predictions of the ultimate strength of the full-scale model. Full article
(This article belongs to the Special Issue Safety and Reliability of Ship and Ocean Engineering Structures)
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15 pages, 2026 KiB  
Article
The Multistate Reliability Assessment of Ship Hull Girders
by Joanna Soszyńska-Budny and Špiro Ivošević
Appl. Sci. 2025, 15(11), 6218; https://doi.org/10.3390/app15116218 - 31 May 2025
Viewed by 308
Abstract
Ships are designed to withstand various types of hull structure damage, including corrosion, fatigue, damage, crack, fouling, etc., throughout their projected life cycle of 25 years. In this study, we used a database of 25 different bulk carriers aged from five to twenty-five [...] Read more.
Ships are designed to withstand various types of hull structure damage, including corrosion, fatigue, damage, crack, fouling, etc., throughout their projected life cycle of 25 years. In this study, we used a database of 25 different bulk carriers aged from five to twenty-five years, consisting of a total of 1920 thickness measurements of girder plate damage across 110 fuel tanks. Thickness measurements of longitudinal girder plate were conducted by certified technicians and approved company. Ultrasound thickness gauging equipment was used to collect data in accordance with the developed methodology and gauging scheme. Based on the classification societies’ rules, the values of the reduction in steel plate thickness due to corrosion over time fall into three categories: acceptable corrosion, substantial corrosion, and extensive corrosion. While classification societies prescribe permissible thickness reductions between 15 and 30%, in this study, the authors considered the excessive corrosion values to be above 20% reduction in initial thickness. Measurements indicating more than 20% reduction were classified as failures, necessitating the replacement of the corroded surfaces. After applying the multistate approach to the reliability analysis of longitudinal girder plates and improving reliability after reaching the critical state, the results show that usability dropped significantly between ten and fifteen years of service for upper girder plating and between twenty and twenty-five years of service for lower girder plates. These findings highlight the crucial impact of gauging location on reliability analysis. Full article
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16 pages, 1813 KiB  
Proceeding Paper
Scaling the Response of a Simplified Hull Girder Subjected to Underwater Explosions
by Giovanni Marchesi, Luca Lomazzi, Marco Giglio and Andrea Manes
Eng. Proc. 2025, 85(1), 19; https://doi.org/10.3390/engproc2025085019 - 19 Feb 2025
Cited by 1 | Viewed by 411
Abstract
Underwater explosions (UNDEXs) represent a significant threat to marine vessels, motivating the analysis of their resulting dynamic response and damage. Conducting experimental investigations on full-scale ships, while being the most consistent strategy, is not always feasible due to obvious economic constraints. Consequently, researchers [...] Read more.
Underwater explosions (UNDEXs) represent a significant threat to marine vessels, motivating the analysis of their resulting dynamic response and damage. Conducting experimental investigations on full-scale ships, while being the most consistent strategy, is not always feasible due to obvious economic constraints. Consequently, researchers usually rely on scaled models designed to replicate real-world scenarios in laboratory environments. Despite the widespread use of this approach, the scaling laws between prototypes and models are not yet satisfactory due to the complexity of the UNDEX phenomena and the variability in boundary conditions. To address this aspect, the present study focuses on the scalability of a simplified vessel, termed a simplified hull girder (SHG). This study is conducted numerically and originates from a comparison with experiments available in the literature. This work has two objectives: firstly, it provides a practical approach to simulating the behaviour of complex architectures that undergo severe deformation due to blast loads, a critical challenge for state-of-the-art computational methods. Secondly, this work aims to assess the reliability of the scaling laws commonly used in UNDEX scenarios and to highlight the importance of strain-rate effects. Full article
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33 pages, 13471 KiB  
Article
Challenges and Constraints in the Application of Rule-Based Hull Girder Load Adjustments: Insights with Future Directions
by Chang Hwan Jang and Do Kyun Kim
Appl. Sci. 2025, 15(3), 1480; https://doi.org/10.3390/app15031480 - 31 Jan 2025
Cited by 4 | Viewed by 997
Abstract
The International Association of Classification Societies (IACS) has introduced the concept of the Equivalent Design Wave (EDW) for the calculation of dynamic loads for structural analysis in the Common Structural Rule (CSR) for the design of bulk carriers and oil tankers. An EDW [...] Read more.
The International Association of Classification Societies (IACS) has introduced the concept of the Equivalent Design Wave (EDW) for the calculation of dynamic loads for structural analysis in the Common Structural Rule (CSR) for the design of bulk carriers and oil tankers. An EDW is a set of loads representing a design wave whose response is equivalent to the required design value at a given probability level. Classification societies are applying the EDW concept by implementing design loading equations for LNG carriers, bulk carriers, and oil tankers. According to the EDW loads, dozens of load cases are generated using the design load formula, and the hull girder loads calculated from them are adjusted to the target values. In this short communication, the hull girder load is adjusted according to the method described in the DNV rule for a cargo hold model of an LNG carrier. The adjusted load is distributed as a nodal force by shear flow and simple beam theory. An alternative method is introduced by comparing existing methods with regard to adjustment methods and load distribution. After discussing existing methods, a method for adjusting all hull girder load components in three steps and a load distribution method using the stress field were derived. The limitation of the current technique and insights summarised in this short communication may support readers in understanding the rule-based hull girder load adjustment technique. In addition, this limitation may clearly motivate the demand for alternative technology development for hull girder load adjustment. Full article
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31 pages, 12922 KiB  
Article
A Novel Hull Girder Design Methodology for Prediction of the Longitudinal Structural Strength of Ships
by Haicheng Yu, Songhao Wu, Yingdong Zhao, Wenlong Liu and Haiyi Yang
J. Mar. Sci. Eng. 2024, 12(12), 2368; https://doi.org/10.3390/jmse12122368 - 23 Dec 2024
Cited by 1 | Viewed by 839
Abstract
The ship hull girder model has been widely adopted in ship mechanics research such as small-scale and large-scale hydroelastic ship model experiments. Current design methods cannot seriously meet the structural rigidity requirement, and the distinction between the ship structural masses and the cargo [...] Read more.
The ship hull girder model has been widely adopted in ship mechanics research such as small-scale and large-scale hydroelastic ship model experiments. Current design methods cannot seriously meet the structural rigidity requirement, and the distinction between the ship structural masses and the cargo masses is rather vague. This research proposes a simple and novel ship hull girder design methodology. The main novelties are that (1) the structural rigidity design requirement for the ship hull girder corresponding to any targeted real ship with arbitrary structural complexity is precisely satisfied by the proposed strategy of adopting a composite hull girder system, and that (2) the mass density per unit length of the proposed hull girder is solely related to the mass density distribution of the targeted ship structures by considering the hull girder system as a complete finite element (FE) model, and thus (3) a better ship hull girder model for prediction of the total structural responses can be consequently established. A real ship is adopted as the design target, and the structural responses of the real ship and the proposed ship hull girder model are compared and analyzed. The proposed model is compared to the currently widely accepted ship hull girder models through numerical experiments. The proposed hull girder design methodology possesses the potential for upgrading the classical structural design approach to match the growing trend of adopting FEM-based approaches for ship structure research. Full article
(This article belongs to the Section Ocean Engineering)
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36 pages, 8874 KiB  
Review
Fatigue Overview of Ship Structures under Induced Wave Loads
by Pasqualino Corigliano, Federico Frisone, Claudia Chianese, Marco Altosole, Vincenzo Piscopo and Antonio Scamardella
J. Mar. Sci. Eng. 2024, 12(9), 1608; https://doi.org/10.3390/jmse12091608 - 10 Sep 2024
Cited by 2 | Viewed by 5528
Abstract
Fatigue damage represents a key failure mode in ship structures. Such damage typically begins at vulnerable points in the structure, like welded joints, stress concentration areas, and cracks. Cyclic loading, particularly from waves, encountered by ships during their operational life is a major [...] Read more.
Fatigue damage represents a key failure mode in ship structures. Such damage typically begins at vulnerable points in the structure, like welded joints, stress concentration areas, and cracks. Cyclic loading, particularly from waves, encountered by ships during their operational life is a major cause of fatigue damage, which is the main focus of this study. There are various methods to address different sea state conditions, though they can sometimes be approximate. This paper aims to review the most commonly used methods to highlight their strengths and weaknesses and to provide essential background knowledge for developing reliable theoretical and numerical models for predicting the fatigue life of ship structures exposed to various sea states over their lifetime. The primary theoretical approaches discussed include energy spectral methods in both time and frequency domains, which are used to quantify wave-related energy and amplitude characteristics and evaluate wave loads for predicting the fatigue life of structures and welded joints. The discussion also covers the determination of cyclic stress in specific structural details of the hull girder and welded joints to identify the relevant maximum stress range for subsequent fatigue studies conducted using finite element analysis. Full article
(This article belongs to the Special Issue Advanced Studies in Marine Mechanical and Naval Engineering)
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21 pages, 11641 KiB  
Article
Study on Strain Field Reconstruction Method of Long-Span Hull Box Girder Based on iFEM
by Guocai Chen, Xueliang Wang, Nan Zhao, Zhentao Jiang, Fei Li, Haozheng Chen, Pengyu Wei and Tao Zhang
J. Mar. Sci. Eng. 2024, 12(9), 1482; https://doi.org/10.3390/jmse12091482 - 26 Aug 2024
Cited by 1 | Viewed by 1349
Abstract
The box girder’s condition significantly impacts the safety and overall performance of the entire ship because it is the primary stress component of the hull construction. This work used experimental research on the long-span hull box girder based on IFEM (Inverse Finite Element [...] Read more.
The box girder’s condition significantly impacts the safety and overall performance of the entire ship because it is the primary stress component of the hull construction. This work used experimental research on the long-span hull box girder based on IFEM (Inverse Finite Element Method) technology to ensure the structural safety of the hull box girder. Due to the limitations of conventional experiments in this technical field, such as their reliance on finite element data and lack of input from physical tests, numerous research methods combining the strain sensing data from physical tests with the strain data from virtual sensors were conducted. The strain fields of the top plate, side plate, and bottom plate were each reconstructed in turn, and the verifier measuring points in the physical model test were used to assess the accuracy of the reconstruction results. The findings demonstrate that the top plate, side plate, and bottom plate reconstructions had relative errors of 0.24–7.86%, 0.75–8.13%, and 3.31–2.52%, respectively. This enables the reconstruction of the strain field of the long-span hull box girder using physical test data and promotes the use of iFEM technology in the field of structural health monitoring of large marine structures. Full article
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21 pages, 33618 KiB  
Article
Research on a Real-Time Prediction Method of Hull Girder Loads Based on Different Recurrent Neural Network Models
by Qiang Wang, Lihong Wu, Chenfeng Li, Xin Chang and Boran Zhang
J. Mar. Sci. Eng. 2024, 12(5), 746; https://doi.org/10.3390/jmse12050746 - 29 Apr 2024
Cited by 5 | Viewed by 1368
Abstract
Real-time prediction of hull girder loads is of great significance for the safety of ship structures. Some scholars have used neural network technology to investigate hull girder load real-time prediction methods based on motion monitoring data. With the development of deep learning technology, [...] Read more.
Real-time prediction of hull girder loads is of great significance for the safety of ship structures. Some scholars have used neural network technology to investigate hull girder load real-time prediction methods based on motion monitoring data. With the development of deep learning technology, a variety of recurrent neural networks have been proposed; however, there is still a lack of systematic comparative analysis on the prediction performance of different networks. In addition, the real motion monitoring data inevitably contains noise, and the effect of data noise has not been fully considered in previous studies. In this paper, four different recurrent neural network models are comparatively investigated, and the effect of different levels of noise on the prediction accuracy of various load components is systematically analyzed. It is found that the GRU network is suitable for predicting the torsional moment and horizontal bending moment, and the LSTM network is suitable for predicting the vertical bending moment. Although filtering has been applied to the original noise data, the prediction accuracy still decreased as the noise level increased. The prediction accuracy of the vertical bending moment and horizontal bending moment is higher than that of the torsional moment. Full article
(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)
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17 pages, 8381 KiB  
Article
Effect of Corrosion-Induced Structural Degradation on the Ultimate Strength of a High-Tensile-Steel Ship Hull
by Nikola Momčilović, Nemanja Ilić, Milan Kalajdžić, Špiro Ivošević and Ana Petrović
J. Mar. Sci. Eng. 2024, 12(5), 745; https://doi.org/10.3390/jmse12050745 - 29 Apr 2024
Cited by 8 | Viewed by 2215
Abstract
Standard structural assessments of ship hulls include the evaluation of the elastic structural response. Elastic analysis neglects extreme and unpredicted loadings, which can produce catastrophic outcomes, such as the loss of the ship’s ultimate strength. Moreover, hull elements are considered unaffected by age-related [...] Read more.
Standard structural assessments of ship hulls include the evaluation of the elastic structural response. Elastic analysis neglects extreme and unpredicted loadings, which can produce catastrophic outcomes, such as the loss of the ship’s ultimate strength. Moreover, hull elements are considered unaffected by age-related degradation. Therefore, this study models and quantifies the effect of corrosion-induced structural degradation on the ultimate strength of a high-tensile-steel (HTS) cargo ship using progressive collapse and nonlinear finite element methods. Uniform and pitting corrosion are modeled through selected scenarios, which hull elements might encounter during exploitation, producing a total of 148 calculation models. The findings show that corrosion-induced degradation can significantly decrease the ultimate strength of the hull (up to 30% for the most severe scenarios assessed). Furthermore, ultimate strength decreases almost proportionally to the amount of wastage considered. It was found that stiffener corrosion has a significant effect on the total ultimate strength. This study’s aim is to emphasize the vast importance of including ultimate strength along with ageing effects in industry-standard structural assessments of large HTS ship structures, designed to last for several decades whilst exposed to excessive and unpredicted bending moments. Full article
(This article belongs to the Special Issue Failure Analysis of Marine Structure II)
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16 pages, 2210 KiB  
Article
Consequences of the Improved Wave Statistics on a Hull Girder Reliability of Double Hull Oil Tankers
by Joško Parunov, Antonio Mikulić and Maro Ćorak
J. Mar. Sci. Eng. 2024, 12(4), 642; https://doi.org/10.3390/jmse12040642 - 11 Apr 2024
Viewed by 1333
Abstract
This paper investigates the change in hull girder failure probabilities and partial safety factors caused by the implementation of the new procedure for direct computation of wave loads recommended by the International Association of Classification Societies (IACS). Differences between new and previous procedures [...] Read more.
This paper investigates the change in hull girder failure probabilities and partial safety factors caused by the implementation of the new procedure for direct computation of wave loads recommended by the International Association of Classification Societies (IACS). Differences between new and previous procedures are primarily related to the different associated scatter diagrams, and secondarily due to the assumptions on wave spectrum, wave energy spreading, and ship speed. This study performs a comparative structural reliability analysis of the global longitudinal bending of five oil tankers of different sizes between two procedures for wave load computation. Firstly, failure probabilities are compared, and secondly, modified partial safety factors are proposed, resulting in similar failure probabilities according to two separate procedures. It is found that implementation of the new revision of the IACS procedure for direct computation of wave loads results in a reduction of the minimum required ultimate vertical bending capacity of a ship hull by 10%. In addition to the novel investigation of the safety of oil tankers using a revised wave scatter diagram, this study offers a new rapid method for calculation of extreme vertical wave bending moments based on the regression of the parameters of the Weibull function, used for the long-term probability distribution of wave-induced loads. Full article
(This article belongs to the Special Issue New Insights into Safety of Ships and Offshore Structures)
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40 pages, 29085 KiB  
Article
A Two-Stage Optimisation of Ship Hull Structure Combining Fractional Factorial Design Technique and NSGA-II Algorithm
by Joynal Abedin, Francis Franklin and S. M. Ikhtiar Mahmud
J. Mar. Sci. Eng. 2024, 12(3), 411; https://doi.org/10.3390/jmse12030411 - 26 Feb 2024
Cited by 2 | Viewed by 2903
Abstract
The intricate nature of ships and floating structures presents a significant challenge for ship designers when determining suitable structural dimensions for maritime applications. This study addresses a critical research gap by focusing on a three-cargo hold model for a multipurpose cargo ship. The [...] Read more.
The intricate nature of ships and floating structures presents a significant challenge for ship designers when determining suitable structural dimensions for maritime applications. This study addresses a critical research gap by focusing on a three-cargo hold model for a multipurpose cargo ship. The complex composition of these structures, including stiffening plates, deck plates, bottom plates, frames, and bulkheads, necessitates thorough structural analysis to facilitate effective and cost-efficient design evaluation. To address this challenge, the research utilises FEMAP-integrated NX NASTRAN software (2021.2) to assess hull girder stress. Furthermore, a novel approach is introduced, integrating the Design of Experiments (DOE) principles within Minitab 21.4.1 software to identify critical parameters affecting hull girder stress and production costs. This method determined the top five key parameters influencing hull girder stress: Hatch coaming plate, Hatch coaming top plate, Main deck plate, Shear strake plate, and Bottom plate, while also highlighting key parameters that impact production costs: the inner bottom plate, Inner side shell plate, Bottom plate, Web frame spacing, and Side shell plate. Ship design optimisation is then carried out by incorporating regression equations from Minitab software into the Non-dominated Sorting Genetic Algorithm II (NSGA-II), which is managed using Python software (PyCharm Community Editon 2020.3.1). This optimisation process yields a significant 10% reduction in both ship weight and production costs compared to the previous design, achieved through prudent adjustments in plate thickness, web frame positioning, and stiffener arrangement. The optimally designed midship section undergoes rigorous validation to ensure conformity with industry standards and classification society regulations. Necessary adjustments to inner bottom plates and double bottom side girders are made to meet these stringent requirements. This research offers a comprehensive framework for the structural optimisation of ship hulls, potentially enhancing safety, sustainability, and competitiveness within the maritime engineering industry. Full article
(This article belongs to the Special Issue Advances in Ships and Marine Structures)
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19 pages, 10431 KiB  
Article
Root Causes of Thin-Plate Buckling Damage at the Aft-End in Crude Oil Tanker and Verification through Buckling Analysis
by Joo-Shin Park and Myung-Su Yi
Metals 2024, 14(2), 158; https://doi.org/10.3390/met14020158 - 28 Jan 2024
Cited by 2 | Viewed by 1996
Abstract
For large ships and offshore vessels, structural safety is verified through whole-ship analysis using commercial software. In the case of general oil tankers, classification rules for structural strength evaluation are uniformly applied. Structural strength evaluation is mainly divided into the cargo hold, fore-end, [...] Read more.
For large ships and offshore vessels, structural safety is verified through whole-ship analysis using commercial software. In the case of general oil tankers, classification rules for structural strength evaluation are uniformly applied. Structural strength evaluation is mainly divided into the cargo hold, fore-end, and aft-end parts. For the structural design of a cargo ship, it is important to calculate the design load and determine the thickness and size of the structural member. Structural FEA (Finite Element Analysis) is performed on only the cargo hold range as recommended by the CSR (Common Structure Rule). There is no FE analysis recommendation for either the aft- or the fore-end area. Therefore, structural safety is carried out based on existing design experience and engineer judgment. With previous approaches, it is difficult to clarify the safety of the aft-end part according to external loads such as hull girder load and local pressure. Recently, local buckling damage cases have investigated the aft-end of the shuttle tanker. Although this is a good example, it can be recognized that it is necessary to improve the accuracy of prediction when estimating the structural safety at the aft-end part. In this study, a novel FE-based evaluation methodology about buckling damage is proposed. In order to conduct a structural strength verification based on FE analysis modeling, reasonable solutions for load conditions, boundary conditions, modeling methods, and evaluation criteria are presented. This result is expected to be helpful in examining the structural strength of the aft-end part of similar carriers in the future. Full article
(This article belongs to the Special Issue Residual Stress Analysis of Welded Structure (Volume II))
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24 pages, 28071 KiB  
Article
A Two-Step Approach for Evaluating the Dynamic Ultimate Load Capacity of Ship Structures
by Weilong Zhang, Jinju Cui and Deyu Wang
J. Mar. Sci. Eng. 2024, 12(2), 219; https://doi.org/10.3390/jmse12020219 - 25 Jan 2024
Cited by 1 | Viewed by 1540
Abstract
One important parameter for evaluating the safety and reliability of a ship is o the dynamic ultimate load capacity of ship structures. Because of the importance of this parameter, its determination is essential. In this paper, a novel “two-step” approach for determining the [...] Read more.
One important parameter for evaluating the safety and reliability of a ship is o the dynamic ultimate load capacity of ship structures. Because of the importance of this parameter, its determination is essential. In this paper, a novel “two-step” approach for determining the dynamic ultimate load capacity of ship structures is proposed. The main idea of two-step approach is to determine the dynamic ultimate load capacity based on the static ultimate load capacity after accounting for impacts that cause strain on the ship structures. This approach is based on nonlinear finite element method. Here, taking stiffened plate as a case study, the practical application of thus two-step approach is discussed in detail. The results of this approach reveal that the static ultimate load capacity decreases by less than 3% after a stiffened plate is subjected to an impact load whose amplitude corresponds to the dynamic ultimate load capacity. Then, the influence of the impact duration on the failure mode and the effect of the impact load cycles and the impact load sequence on the dynamic ultimate load capacity of the stiffened plate were investigated. Finally, the applicability of the two-step approach to a hull girder is demonstrated. The two-step approach and the conclusions presented in this paper can provide guidance for the evaluation of dynamic ultimate load capacity. Full article
(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)
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26 pages, 119937 KiB  
Article
Linear Longitudinal Strength Analysis of a Multipurpose Cargo Ship under Combined Bending and Torsional Load
by Joynal Abedin, Francis Franklin and S. M. Ikhtiar Mahmud
J. Mar. Sci. Eng. 2024, 12(1), 59; https://doi.org/10.3390/jmse12010059 - 26 Dec 2023
Cited by 2 | Viewed by 3857
Abstract
Cargo ships with wide hatches usually have thin walls and limited torsional rigidity. Consequently, conducting a comprehensive torsional analysis is important because these loads can exert a significant impact. In this paper, the structural response of a multipurpose cargo ship to combined bending [...] Read more.
Cargo ships with wide hatches usually have thin walls and limited torsional rigidity. Consequently, conducting a comprehensive torsional analysis is important because these loads can exert a significant impact. In this paper, the structural response of a multipurpose cargo ship to combined bending and torsional loads is studied using finite element analysis. The bending and torsional moments are calculated following the rules and standard regulations followed by the classification society. The ship’s 3D finite element model was verified using beam theory and direct calculations. In contrast, the accuracy of torsional stress was confirmed by comparing thin wall girder theory with direct calculation results. This study thoroughly examined the impacts of the still water bending moment, the vertical wave bending moment, and the wave-induced torsional moment on the structural response of ships. Furthermore, it scrutinised the impact of torsion on both open-deck and closed-deck ships. Hull girder normal stresses at midship due to still water and the vertical wave bending moment are shown to contribute to almost 70% of total stress in an inclined condition; stresses resulting from the horizontal wave bending moment contribute nearly 10%, while warping stresses contribute approximately 20% in open-deck ships. It is also shown that torsion has little impact on closed-deck ships. Finally, a buckling analysis was conducted to assess the ship’s buckling criteria, confirming that the linear buckling criteria were satisfied. Full article
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15 pages, 5367 KiB  
Article
Ultimate Strength Behaviour and Optimization of Laser-Welded Web-Core Sandwich Panels under In-Plane Compression
by Mohamed Elsaka and C. Guedes Soares
J. Mar. Sci. Eng. 2023, 11(11), 2200; https://doi.org/10.3390/jmse11112200 - 19 Nov 2023
Cited by 1 | Viewed by 1756
Abstract
In pursuit of more efficient load-bearing solutions for ship deck panels of Very Large Crude Carriers exposed to vertical hull girder bending forces, laser-welded web-core sandwich panels are considered as an alternative to conventional stiffened panels. The primary goal is to identify a [...] Read more.
In pursuit of more efficient load-bearing solutions for ship deck panels of Very Large Crude Carriers exposed to vertical hull girder bending forces, laser-welded web-core sandwich panels are considered as an alternative to conventional stiffened panels. The primary goal is to identify a lighter steel sandwich structure capable of matching the ultimate strength of conventional counterparts. Utilizing non-linear finite element analysis, the ultimate strength of conventional decks subjected to uniaxial compression is assessed. Attention is then shifted to laser-welded sandwich panels, with a detailed examination of how various design parameters influence their performance. Specifically, four key design aspects of unidirectional vertical webs, including face thickness, web thickness, web height, and web spacing, are optimized to strike a balance between weight and strength through structural optimization techniques combined with the response surface method. Ultimately, a comparison is drawn between the ultimate strength of these innovative steel sandwich panels and their conventional, stiffened counterparts. The findings reveal that web-core sandwich panels, when employed as an alternative, result in a notable reduction in hull weight, thereby showcasing the potential for a more efficient and sustainable approach in the maritime industry. Full article
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