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In the field of ocean engineering, the variation of flow field during ship-to-ship (STS) interaction has been a hot topic. Noteworthy, the effect of vortex distribution on flow field characteristic variations during STS interaction remains insufficiently researched. This study modifies the RNG k-ε model using the OpenFOAM platform and verifies its reliability by comparing it with literature data. Subsequently, extended research is conducted to investigate the flow field characteristics of two different ship hull sections under different Reynolds numbers (Re=68,000 and Re=6800), analyzing velocity components, vortex distribution, and trends in pressure and turbulent kinetic energy fields relative to the vortex field. The research reveals that Re primarily governs changes in upstream and downstream flow fields, while in the gap field, the variation in flow field characteristics is more constrained by geometry and boundary conditions. This research provides a valuable reference for assessing flow field characteristics in STS interactions.

The deck is one of the ship constructions located above the draft. The deck structure must be designed appropriately, especially at the corner side. This is caused by the impact of water flowing on the deck. As a result of this water flowing, the side corner of the deck must be constructed so that water does not pool on the deck. The aim of this study is to examine how the shape of the deck-side corner affects the ultimate strength of a double-hull ship. Three models of double-hull boats are considered to be investigated with different shapes of deck side corners. The ship’s dimensions are 42 meters in width and 20.3 meters in depth. The longitudinal direction with respect to length is considered one frame space of 5 m. The three models ’ breadth, depth, and length dimensions are constant. The material properties, such as density, yield strength, elastic modulus, and Poisson’s ratio, are assumed to remain constant. The analysis focuses on the cross-section of the double-hull ship. In this study, the influence of the deck side corner shape on ultimate strength is investigated using the Multiple Point Constraint (MPC) method. The position of the neutral axis is determined in advance to allow for the placement of the MPC. The MPC is applied to one side of the cross-section, while the opposite side is fixed securely. A four-node quadrilateral shell element is used in the Finite Element Method to model the entire cross-section of the double-hull ship. The analysis shows that the first model of the double hull ship has the highest ultimate strength, followed by the second model, with the third model having the lowest strength.

Ship construction typically includes single hull and double hull designs, each offering distinct advantages and disadvantages concerning the ship’s ultimate strength. Because a single hull does not have an inner hull or inner bottom, it may carry more cargo than a double hull. Compared to a single hull, a double hull offers greater safety during collisions and grounding incidents due to the presence of an additional inner hull and inner bottom. As a result, this influence has to be examined in relation to the ship design and construction specifications. This study aims to examine how damage impacts the ultimate strength of single and double hull ship designs when subjected to hogging and sagging conditions. Both single and double hulls’ midship cross sections are considered in the study. One side of the cross section is rotated by a force, while the other side is fixed under restrictions. In this case, just one side of the cross section is subject to the multiple point constraint. It is assumed that the midship cross section will remain flat during the gradual collapse process. The materials have uniform density, yield strength, Poisson’s ratio, and Young’s modulus, with single hull and double hull ships having identical proportions. An inner hull is incorporated into the simulation for the double hull structure. For simple analysis, longitudinal direction is done in a single frame space. This study employs an analytical method to assess the effects of damage on the structural integrity of single-hull and double-hull ships. The findings reveal that damage has a notable influence on the ultimate strength of both hull types. The moment-curvature relationship is utilized to represent the ultimate strength of these structures. Additionally, the paper illustrates the deformation patterns and stress distributions in single hull and double hull designs.

Liu, X.; Hu, Y., and Xiao, C.-S., 2019. A new robust and fast iterative closest point algorithm for 3D Ship Hull Plate Bending Machines. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 264–268. Coconut Creek (Florida), ISSN 0749-0208. The registration accuracy has a direct impact on the processing accuracy of sheet metal in 3D Ship Hull Plate Bending Machines. This study introduces a new distance measure, Root-Mean-Squared iterative closest point (RMS-ICP) algorithm to significantly improve the robustness of the algorithm, and reduce the influence of outliers. At the same time, the 3D point sets registration algorithm is optimized. In addition, the RMS-ICP has been optimized in robustness, registration accuracy and convergence speed in comparison with the original ICP and other improved ICP algorithms. The experiment results support that the performance of the RMS-ICP algorithm is better than other methods. Overall, the RMS-ICP algorithm is very effective in dealing with the point sets registration problem in 3D Ship Hull Plate Bending Machine.

Recently, the NURBS technique has been widely used in the 3D design software for ships. However, in most research, the NURBS technique is only applied to the mathematical representation of hull curves and surfaces, and the parametric deformation of hull surfaces based on geometric feature parameters is less understood. The aims of this paper are to establish the parametric design process of hull surfaces through the classification of geometric feature parameters and the design of feature curves, apply the NURBS technique to the parametric geometric modeling of hull curves and surfaces, and finally achieve the parametric deformation of hull surfaces driven by geometric feature parameters and develop the parametric deformation software. Taking the Series 60 ship as an example, we first analyze the hull geometric features and parameters, then design the longitudinal feature curves and cross-section curves based on the NURBS technique and establish the correlation between them, and finally generate the smooth hull surface by the skinning technique to achieve the parametric geometric deformation of the Series 60 ship. The research in this paper shows that the smoothness of the surfaces generated by the NURBS-based parametric design method is good. Additionally, the extracted feature parameters have a clear geometric meaning and can automatically generate hull forms to meet the design requirements quickly and effectively, which has some practical engineering value.

The objective of the present study is to analyze the progressive collapse of VLCC hull girder with damages subjected to longitudinal bending. For the simple case, the cross-section is assumed to be remained plane and the vertical bending moment is applied to the cross section. The residual stress, initial imperfection, and crack are not considered. The damages scenarios are located at the center part and asymmetric position of the cross section. To analyze the progressive collapse including its behavior of VLCC ship hull, the simply supported is imposed to the cross section and taking the hogging and sagging condition into account. The results obtained for intact and damages condition by the analytical solution is compared and summarized with one another.

A double hull tanker is one of the specific ships where the payload is liquid. The payload is an internal load and gives pressure inside the cargo hold. Besides, the external load like wave act simultaneously on the ship during the voyage. Therefore, the ultimate strength of the ship caused by the internal and external loads must be investigated. The objective of the present study is to investigate the ultimate strength characteristic of double hull oil tankers under hogging and sagging conditions. The cross-section of the double hull tanker is modeled using the finite element method to analyze the ultimate strength. The master node is applied to both sides of the cross-section to know the characteristic of the hull girder under hogging and sagging conditions. One side of the master node is constrained, and the other one is given by rotational force. The analytical method is performed, and the result obtained by the numerical method is then compared, including their characteristic in terms of moment-curvature relationship and deformation.

A high-order fractional step finite volume solver is developed with a fractional step method along with an explicit fourth-order Runge–Kutta scheme in solving Navier–Stokes equations. And then the solver is applied to the prediction of the longitudinal distribution of cross-sectional ship roll hydrodynamics. The present development ameliorates the previous high-order finite volume solver [Ocean Eng 180:119–129] in solving the pressure–velocity coupled equation to further enhance its robustness on roll simulation. Firstly, accuracy of the solver is validated by shear-driven cavity flows and a series of roll motions with the available published numerical or experimental results. And its convergency is verified with a grid- and time step-dependence study. Then, a roll simulation on the mid-section of a KVLCC2 is performed; it embodies that the present solver can suppress the force oscillation than the previous one [Ocean Eng 180:119–129]. Finally, harmonic excited roll motions for several cross sections of a KVLCC2 are systematically investigated for cases of different roll amplitudes and frequencies. And longitudinal distributions of roll hydrodynamics and flow structures near the ship hull are analyzed. In results, the present solver enhances the robustness on roll simulation compared with the previous one [Ocean Eng 180:119–129]. Roll hydrodynamic coefficients culminate at sections of the parallel middle body, and decrease gradually towards fore and aft, and then they increase at the bow and stern.

The hull girder plays an important role against those loads and to describe the structural behavior under longitudinal bending. The hull cross-sectional properties have a significant contribution to the ultimate strength investigation. Therefore, the influence of the element section properties to the ultimate hull girder strength must be evaluated. The objective of the present study is to calculate the ultimate hull girder strength considering the element section properties subjected to longitudinal bending. Two double-hull tankers are taken with the same dimension, but different from the element section properties characteristic such as number, dimension, and type of the stiffeners located on the bottom, shell and deck parts. The basic formula is adopted to calculate element section properties of the hull girder for double hull tanker. The double hull tanker is modeled as a cross-section having the stiffeners and attached plating. The stress due to the difference of the element section properties is less than allowable stress.

The objective of the present research is to study the ultimate strength of ship’s hull considering cross section and beam finite element under longitudinal bending. The single hull bulk carrier and double hull oil tanker are taken to be analysed. The one-frame space of ship is considered in the calculation. The cross section of ship’s hull is divided into element composed plate and stiffened plate. The cross section is assumed to be remained plane and the simply supported is imposed to both side of the cross section. The longitudinal bending moment is applied to the cross section for hogging and sagging condition. The Smith’s method is adopted and implemented into the in-house program of the cross section and beam finite element to calculate the ultimate strength of ship’s hull. The result of the ultimate strength for hogging and sagging condition obtained by considering the cross section and beam finite element is compared with one another.