Ship Side Research Articles

Study on the jetting characteristics of an underwater explosion bubble collapsing near a floating body

This study explores the dynamic behavior and jet characteristics of underwater explosion (UNDEX) bubble oscillating near a rigid floating body using the arbitrary Lagrangian–Eulerian (ALE) method. Experiments on UNDEX bubble oscillating in a free field or oscillating near a rigid floating body in an explosion tank are used to validate the effectiveness of the ALE method in simulating the behaviors of high pressure bubble oscillating near a boundary in water. The numerical results are in good agreement with the experimental data. On this basis, the distribution of the field pressure and velocity of the oscillating bubble are further analyzed in detail. The evolution characteristics of the bubble jets are discussed for various values of the stand-off distance and explosion attack angle. The results reveal that a bubble produces two jet patterns for close stand-off distances (from γD=0.800 to γD=1.336) and attack angles of 0°, 45°, 75°, and 90°. The first bubble jet results in an annular splitting of the bubble, while the second jet is pointed toward the floating body. The aim of this study is to provide a reference for further understanding the jet dynamics of UNDEX bubble collapsing near a structure and the effective attack on ship sides.

Research on the response of underwater explosion side structure based on RKPM method

Abstract Based on smoothed particle hydrodynamics and reproducing kernel particle method, this paper establishes a fluid-structure interaction three-dimensional calculation model for the dynamic response of complex structures to underwater explosion shockwave, verifies the effectiveness, accuracy and progressiveness of SPH-RKPM coupling calculation, and establishes a control condition with detonation distance as a variable to determine the dynamic response characteristics of ship side under shockwave loads generated by underwater explosion at different detonation distances.

Mechanical analysis and interior stiffeners arrangement discussion of a specific ship side collision situation

Collision between ships of different sizes may result in a situation where a vessel with a higher deck height impacts another vessel with a lower deck height. In such case, the absence of bearing structure above the lower-draft struck ship's deck means that the bow of the high-draft striking ship transfers pressure to both the deck and side plates of the struck ship during collision. According to this situation, the numerical simulation of small scale compartment impacted by a higher-draft ship bow was carried out. Based on the analysis of the numerical results, the main impact area of the small scale compartment was simplified into a typical L-shaped plate-frame structure to facilitate the experiment. A small scale quasi-static experiment was implemented and the force-displacement curve and energy absorption data of the L-shaped structure penetrated by a rigid approximate bow indenter were obtained. Moreover, material tensile tests provided parameters for numerical simulation and the deformation process of the structure was analyzed. Based on that, several L-shaped structure cases with different stiffeners of height and position were calculated in LS-DYNA. Failure process, structural energy absorption and efficiency were summarized and the excellent structural characteristics for this ship side collision situation were obtained.

Game theory based maritime area detection for cloud-edge collaboration satellite network

Maritime area detection technology applies equipment such as high-orbit satellites, gateway ships and Unmanned Aerial Vehicles to detection. In this scenario, real-time uploading and analysis of maritime data is crucial. In the existing scenario, UAV data are gathered to the gateway ship and uploaded to the shore-based cloud via the high-orbit satellite, because the communication distance of the high-orbit satellite is far, and when the uploaded data volume is large or the access to the equipment increases, the propagation delay of the uploading of the data from the gateway ship to the satellite and the forwarding of the data from the satellite to the shore-based cloud is longer, and the processing delay of the shore-based cloud is increased, and the efficiency of the data transmission and communication will be affected as well. Aiming at the problem of increasing delay caused by communication limitations in maritime area detection, this paper proposes a maritime area detection scheme based on cloud-side collaboration. The scheme solves the problem of communication limitation from the following two aspects. First, the edge computing nodes are deployed on the ship side of the gateway, and the optimal offloading ratio is sought through game theory to offload a part of the tasks from the center cloud to the edge cloud for processing, which improves the efficiency of processing data and thus reduces the data transmission latency and data processing delay. Secondly, low-orbit (LEO) satellites are introduced to provide communication services, because low-orbit satellites have low orbital altitude and short propagation delay, which can transmit the data at the gateway ship to the shore-based cloud more quickly and improve the data transmission efficiency. Finally, it is also verified by designing experiments that the proposed scheme adopts the optimal offloading ratio and has a lower total delay than the original scheme, thus proving the effectiveness of the proposed scheme.

A life cycle cost analysis of different shore power incentive policies on both shore and ship sides based on system dynamics and a Chinese port case.

Shore power (SP) is widely recognized as an efficient strategy for reducing air pollution in port areas. Unfortunately, the adoption of SP has been relatively low, resulting in limited emission reductions and financial losses. To address these challenges, this paper focuses on enhancing the utilization rate of SP, which is meaningful for emission control and environmental protection. This paper combines system dynamics with a study of the benefits of SP, which bridges the research gap to some extent. We propose a system dynamics model that assesses the impact of various incentive policies on the economic and environmental benefits of SP. The model considers the life cycle cost and comprises four subsystems. By conducting a case study on Nansha Port, we find that price subsidies are more effective than construction subsidies in overcoming economic barriers. Furthermore, we observe that the overall economic benefits only increase when the electricity price decreases. This is because lowering the electricity price enhances the profitability of ships without negatively affecting port revenue. Additionally, it is the proportion of the electricity price and service price that determines the overall economic benefits, rather than the SP price itself. Hence, it is recommended to provide preferential subsidies for the electricity price.

Versatile closed-cell SiC/C foam for microwave absorption under medium temperature, icing and mechanical conditions

Microwave-absorbing materials (MAMs) for applications such as aircraft protective layers and ship side panels often need to take into account the actual working conditions. Conventional MAMs are often difficult to take into account special functional requirements such as mechanics, high temperature, de-icing, etc. Therefore, there is an urgent need to develop MAMs with harsh environmental adaptability and multifunctional requirements.Here, we utilize SiO2 microspheres and phenolic resin to prepare precursor foams, and through calcination, we have prepared closed-cell SiC/C foam composites with both microwave absorption properties, mechanical properties and thermal properties. The effective absorption bandwidth (EAB) of the samples is up to 6.9 GHz at a thickness of 7.3 mm, which can satisfy the perfect coverage of the C-band, and can be further broadened by structural design. The samples can satisfy the full coverage of the X-band at 200 °C. The samples have loaded properties, and the maximum compressive strength of the samples is up to 10.5 mm. The samples are loaded with a maximum compression strength of 8 MPa, support repeated medium-temperature heating, and maintain a compression performance of 5.7 MPa after heating. The samples have good thermal conductivity and Joule thermal properties, and the surface temperature can be rapidly increased under the condition of applying a heat source or applying a low pressure to cope with the cold and humid working conditions. The composites in this paper are simple to prepare and have the potential for mass production.

Effect of Manual System in Handling Documents Clearance in and Out Ship Service, Loading and Unloading Ship agency by PT. Bahari Eka Nusantara Sangkulirang branch, East Kalimantan

Bulk ship handling activities cannot be separated from the ship handling service plan, namely the arrival and departure of ships. Before the process of arrival and departure of the ship, several activities are carried out which are determined in advance by the shipping company together with the port manager and must be conveyed to the ship's side. The loading and unloading of ships coming and going, loading and unloading coal, requesting ship needs, handling clearance in and clearance out documents through Syahbandar manually whose service hours are limited, starting from 8 o'clock to 10 pm due to the shahbandar class which is still classified as KUPP class III, and also greatly limiting the movement and service of the ship service served. The purpose of this study is to find out how much influence the management of clearance documents in and out becomes longer, limited operating hours and delays in the loading and unloading process of ships, which are agentized by PT. Bahari Eka Nusantara Sangkulirang Branch, East Kalimantan. The approach method used is a descriptive quantitative method, while the data collection technique uses questionnaires, documentation, observations, and literature studies so that the influence / not between the manual clearance in and out system can be found on the service of the ship being inundated. The results of this study show that there is an influence between the manual clearance in and out system on the service of the ship being inundated.

An analytical method for predicting the structural response of ship side structures by bulbous bow in oblique collision scenarios

ABSTRACT As more and more ships sail on the sea, the probability of collision between ships also increases. At present, researches more on head-on ship collisions than oblique ship collisions. According to statistical data, the probability of oblique ship collision is higher than that of head-on ship collision, and oblique ship collision may cause a wider range of structural damage. Therefore, this paper studies the damage deformation of ship side structures in oblique collision scenarios. In this paper, a simplified analysis method is proposed to predict the structural response of the struck ship’s side structures by bulbous bow in oblique collision scenarios and the analytical results match well with the numerical simulation results, which verifies the accuracy of the simplified analysis method. The simplified analysis method can be used to assess the crashworthiness of ship side structures by bulbous bow in oblique collision scenarios.

Study of Influencing Factors on CFD Method and Separated Flow by the Virtual Static Captive Test

In this paper, Computational Fluid Dynamic (CFD) methods are adopted to predict the manoeuvring behaviour of the KCS benchmark model. At first instance, the model is calibrated on the basis of three factors namely (a) turbulence model, (b) grid size and (c) time step. Secondly, a Static Oblique Towing Test (OTT) that utilises the SST K-ω turbulence model with a grid number of 1.64 million and a time step of 0.01 s is conducted. The maximum difference of the lateral force between the port and starboard ship sides is observed at x/Lpp = 0.055. Finally, application of Reynold Averaged Navier Stokes (RANS) and Dettached Eddy Simulation (DES) CFD models indicates that the latter may be preferable in terms of capturing the oblique flow field.

Anomaly-Based Ship Detection Using SP Feature-Space Learning with False-Alarm Control in Sea-Surface SAR Images

Synthetic aperture radar (SAR) can provide high-resolution and large-scale maritime monitoring, which is beneficial to ship detection. However, ship-detection performance is significantly affected by the complexity of environments, such as uneven scattering of ship targets, the existence of speckle noise, ship side lobes, etc. In this paper, we present a novel anomaly-based detection method for ships using feature learning for superpixel (SP) processing cells. First, the multi-feature extraction of the SP cell is carried out, and to improve the discriminating ability for ship targets and clutter, we use the boundary feature described by the Haar-like descriptor, the saliency texture feature described by the non-uniform local binary pattern (LBP), and the intensity attention contrast feature to construct a three-dimensional (3D) feature space. Besides the feature extraction, the target classifier or determination is another key step in ship-detection processing, and therefore, the improved clutter-only feature-learning (COFL) strategy with false-alarm control is designed. In detection performance analyses, the public datasets HRSID and LS-SSDD-v1.0 are used to verify the method’s effectiveness. Many experimental results show that the proposed method can significantly improve the detection performance of ship targets, and has a high detection rate and low false-alarm rate in complex background and multi-target marine environments.

Experimental and numerical investigation of the damage characteristics of a ship side plate laterally punched by a scaled raked bow indenter

Experimental and numerical simulation studies are conducted on a scaled ship side-shell quasi-statically punched at the mid-span by a raked bow indenter to investigate its damage characteristics from deformation to a large opening. A scaled stiffened panel and a raked bow indenter are designed in model tests. Numerical simulation is performed to simulate the indentation responses. The experimental and numerical results are compared well in terms of resistance-penetration curves, final damage shapes and especially the three failure models, i.e., initial fracture, model “I” crack and model “III” crack. In addition, the whole damage process, the energy dissipation characteristics of the specimen and failure related parameters in three specific failed elements corresponding to the three failure models are analyzed through numerical simulation. The results demonstrate that the energy dissipated by the stiffener and frictional effect is substantial during the crack propagation process. In addition, shell elements involved with three failure models prior to fracture are mainly subjected to tension and bending effects, as shell elements cannot satisfactorily simulate the transverse shear effect. Finally, the influences of collision parameters, the failure sequence of integration points, modeling of weld seams, mesh resolution and failure criteria on the numerical simulation results are discussed.

Influence of propeller on brash ice loads and pressure fluctuation for a reversing polar ship

When a polar ship is stuck in ice-covered waters, reversing operation is an effective way for it to escape from ice. During this operation, rotational propeller will affect flow field and motion of brash ice, thus affecting ice loads and pressure fluctuation. In this paper, a new coupling model using Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) is proposed to investigate characteristics of brash ice loads and pressure fluctuation for a polar ship reversing in a brash ice channel. The present method is well validated by model tests of a towing polar ship in brash ice channel. The simulation results show that in reversing process, brash ice blocks collide with the stern and two sides of ship, where ice blocks accumulate. When the reversing speed is low, the pumping action and acceleration effect of the propeller on the brash ice are obvious. The pumping action reduces the average value of the longitudinal and vertical ice loads, and the acceleration effect makes ice loads occur multiple peaks. The increase in reversing speed worsens the performance of propeller, weakening the pumping action and acceleration effect. The pressure fluctuation period is consistent with propeller rotation period, which decreases for poor propeller propulsion caused by higher reversing speed. It is necessary to strengthen the stern structure in reversing process, especially at low speed, for pumping action and acceleration effect of propeller.

Environmentally Sustainable, Ecologically Conservable and Economical Viable Design and Construction Solution of Ship Side Launching Wharf

India is on development path and construction of various infrastructures work is happening at increasing pace and magnitude. The cement and reinforcement are most essential materials required for a infrastructure projects. Both cement and steel production produce large amount of carbon di oxide and also require large amount of energy for production. This is one main aspect of environmental destruction. Ship building activities are ever increasing in India and so construction of new shipyards and modernization of existing shipyards. Launching of ship is one of the most important operations in the entire ship construction process. Getting permissions for such construction involves various authorities and agencies such as concerned Industrial Development Corporation, River Navigation Department, Caption of Ports, Coastal Regulation Zone Authority, Pollution Control Board to name a few. This paper presents some important aspects of environmentally sustainable, ecologically conservable and economical solution Design and Construction Solution of Ship Side Launching Wharfby substituting conventional RCC piles by rammed stone columns to a large extent and use of gabion walls for closing the face of jetty in place of steel or RCC sheet pile making use of locally available quarry stones.

Large deflection resistance and fracture of panels subjected to the lateral penetration

This paper is concerned with the plastic behaviors of a rigid indenter into a typical ship side panel with analytical and numerical studies. The focus is on a more comprehensive framework where panel dimensions, indenter shapes, and material failure properties are allowed to change when predicting panel failure initiation and the deformation resistance force. Therefore, concise analytical solutions are derived by the plastic membrane and fracture based on a global stability criterion for large deflection. The power curve fitting to the analytical solutions brings out the brief-expression where the influence of geometric and material parameters is present clearly. In addition, the shape factor CS is introduced to illustrate the indenter's sharpness and enable the semi-analytical solutions to deal with the indenter with various geometries:Experimental results of specimens with a range of dimensions punched by indenters presented in the previous work are used to validate the proposed analytical solutions. Numerical simulations are supplemented and demonstrate that the penetration to fracture initiation and the large deflection resistance are sensitive to specimen dimensions and shape and can be predicted accurately by the proposed solutions. Moreover, the applied fracture criterion in analysis considered the change of the geometric and material properties shows consistency with the numerical observations that panel fails by localized necking. By the extension based on the deformation assumption, the corrected procedure enables the prediction of stiffened panels.

Eliminating the influence of measuring point failure in ice load identification of polar ship structures

Ice loads are extreme environmental loads for polar ships sailing in ice regions. Field measurement of polar ship structures is the most direct approach for obtaining ice loads. This study investigates the influence of measuring point failure in ice load identification of polar ship structures and consequently proposes effective practices to eliminate this influence considerably. Based on the simulated strain of a typical polar ship's side grillage, the influence is studied in detail, and the spatial distribution characteristics of the identification error in the monitoring area are subsequently determined. According to the systematic analysis of the strain data at measuring points along frames, the spatial distribution characteristics of the strains are determined and further verified considering typical load scenarios. Consequently, the least squares fitting (LSF) method for the estimation of the strains at failed points is proposed. Practical schemes for ice load identification using the influence coefficient matrix (ICM) method under the influence of measuring point failure are presented and discussed as well. It is found that the LSF method decreases the identification error in the loading area, thereby significantly eliminating the influence. Thus, the scheme associating subarea combination with strain fitting results in higher fineness and better accuracy of ice load identification, which is recommended for adoption and has broad application prospects in the future.

Selection Of Profiles In Midship Vessel Structure Operating The Regulations Of The Indonesian Classification Bureau

Ship construction generally consists of two main parts: the hull and the superstructure or deck house. Several factors must be considered in the construction of a ship. Planning the characteristics of the ship's hull, we are also planning the strength and structure of the ship itself. Midship construction is a construction that must have serious attention in calculating the ship structure. In this section, many forces are acting so that there is a relatively large risk of structural failure. One of the world's classification institutions is BKI, which provides rules for selecting structural profiles. Based on these rules, the load on ship sides is 71,284 KN/m2. Load on the ship bottom is 76,795 KN/m2, Deck Load on Deck Superstructures is 32,581 KN/m2, Load on Cargo Deck is 57,330 KN/m2, Load on Inner Bottom is 68,212 KN/m2, Load on Accommodation Decks is 3,981 KN/ m2.

Selection Of Profiles In Midship Vessel Structure Operating The Regulations Of The Indonesian Classification Bureau

Ship construction generally consists of two main parts: the hull and the superstructure or deck house. Several factors must be considered in the construction of a ship. Planning the characteristics of the ship's hull, we are also planning the strength and structure of the ship itself. Midship construction is a construction that must have serious attention in calculating the ship structure. In this section, many forces are acting so that there is a relatively large risk of structural failure. One of the world's classification institutions is BKI, which provides rules for selecting structural profiles. Based on these rules, the load on ship sides is 71,284 KN/m2. Load on the ship bottom is 76,795 KN/m2, Deck Load on Deck Superstructures is 32,581 KN/m2, Load on Cargo Deck is 57,330 KN/m2, Load on Inner Bottom is 68,212 KN/m2, Load on Accommodation Decks is 3,981 KN/ m2.

Numerical simulation on Crashworthiness of 105000t LNG Carrier

It is of great significance to study the crashworthiness of LNG carrier to improve its crashresistance and enhance its operation safety. In this paper, the collision process between the bulbous bow of the container ship and the side structure of the LNG ship is analyzed by using nonlinear finite element numerical simulation. Collision performance of LNG carrier and collision indicators during the collision, the impact force, velocity and displacement and energy absorption in the process of collision by changing parameters of the major velocity, impact angle and impact location and others are studied. The relevant research results have a strong practical significance for analyzing the deformation, strengthening measures and structural repair of ship side structure impact damage.

Numerical simulation analysis of the collision between ship side and small iceberg

Objectives Collisions between a side structure of ship and a small iceberg are investigated. Methods a nonlinear finite element model is established, involving the penalty function method and arbitrary Lagrangian-Eulerian (ALE) algorithm. A numerical simulation of the interaction between the double-sided structure of a tanker and a spherical iceberg is conducted. The numerical model considers the structural deformation, iceberg damage and hydrodynamic effects during the collision process. The effects of collision angle on collision velocity, contact force and structural energy absorption are also analyzed. Results The results show that the numerical model simulates the interaction between the structure on ship side and small iceberg in as much detail as possible. During the collision process, the peak value of the contact force is closely related to the collision angle and iceberg damage. The contact force increases with the collision angle. Compared to other collision angles, fluid has a significant effect on the iceberg's velocity decay in a normal contact case. Among the structural components of the side structure of tanker, the side shell appears to absorb the most energy. Besides, when the small iceberg is broken, the structural energy absorption decreases and the increasing degree is smaller than in unbroken cases due to the energy loss during the breaking process. Conclusions To ensure the safety of polar ships, the strength of the side structure should be enhanced and a wide collision angle avoided when colliding with small icebergs.

A CFD STUDY ON WIND ASSISTED PROPULSION TECHNOLOGY FOR COMMERCIAL SHIPPING

Wind assisted propulsion has the potential to significantly reduce emissions from global shipping, with a range of technologies available including wing sails, kites, Flettner Rotors, and Suction Aerofoils such as Turbosails. Despite this, there are only a few studies publicly available on the performance of Suction Aerofoils, which operate on the same principle as a traditional sail but use boundary layer suction to develop high lift coefficients. Therefore, a CFD study was carried out in Numeca FINE/Marine software to determine values for the lift and drag coefficients over a range of angles of attack and suction levels. Supplementary studies also investigated the effects of introducing an endplate to reduce end vortices, and the effect of a ship side on the wind speed incident on the Suction Aerofoil. The plots of lift and drag coefficients developed in this paper were used to inform the BMT-led VTAS project [1], as well as contributing to wider knowledge on wind assisted propulsion for shipping. Throughout the study, Suction Aerofoils continued to show promise as an effective means of auxiliary propulsion for ships, and their use should be encouraged as part of the range of solutions to tackle the pressing issue of climate change.