In the present study, the influence of bed slope on the hydrodynamic performance of a floating oscillating water column (OWC) device is investigated. Numerical computations are performed using the incompressible multiphase volume of fluid (VOF) approach. A dynamic meshing technique is adapted to capture the body motions for different wave conditions. The flow phenomena as well as the free surface elevations

The complexity corresponding to the industrial projects and their management are concepts whose interest is increasing. The structural complexity derives directly from the main characteristics of complex systems, that is, many elements that interact, resulting in this structure of great importance in engineering projects. As well as in today’s world, the attempts of organisations to be competitive

ABSTRACT A reliable simulation model to calculate the motion and force responses of wave energy converters (WECs) is imperative to ensure the reliability and long-term performance of WEC systems; these aspects are fundamental to achieving full commercialisation of wave energy. A simulation model was developed and validated concerning the simulated WEC buoy motions in a previous study; this study validated

In this paper, due to the special shape of the sandglass-type floating body, the characteristic of heave damping of the sandglass-type floating production, storage and offloading (FPSO) unit is mainly discussed by the computational fluid dynamics method. Firstly, the numerical model for free heave decay motion of the sandglass-type floating body was created, and the accuracy of the numerical model has

This paper is presented to calculate the hydrodynamic characteristics of the Voith-Schneider Propeller (VSP) and its optimisation scheme applied to the vessels using genetic algorithm (GA). VSP is an efficient propulsion system in manoeuvring of service vessels such as tugs, offshore vessels, workboats and some other vessels. In this study, hydrodynamic forces of thrust and torque are considered as

The quayside container crane (QCC) scale models for seismic simulation test on vibration tables are often high, and the model size and QCC structural size differences introduce discrepancies into the QCC model. In this investigation, discrepancies in the QCC scale model were solved using the similarity method for the sectional radius of inertia. Firstly, a governing equation for the beam section size

Hydrate formation and wax deposition in submarine pipelines hinder the transportation of oil and gas. Pigging operation is an important means to ensure pipeline flow assurance. In this paper, the idea of coiled tubing (CT) intervening in hydrate and wax removal of underwater pipeline is put forward, and the feasibility of this method is discussed from the point of view of the ultimate extension capacity

The aim of this paper is to present a fire test database on the collapse of a full-scale steel stiffened plate structure without passive fire protection under lateral patch loading. Steel plate panels of an as-built 1900 TEU containership in compliance with test facility in a maximum size and capacity were considered as a reference structure, with principal dimensions of 7 m long and 4.8 m wide fitted

Due to cargo loads or weather loads above decks and elastic deformations of the ship’s hull, hatch covers will subject to transverse loads. However, the existing formulas for transverse ultimate capacity evaluation are not applicable to U-type panels due to a higher rotation constraint. This paper is to find an accurate evaluation method of transverses ultimate capacity for U-type stiffened panels

Hydrodynamic coefficients of subsea manifolds are significant parameters in predicting dynamic responses during deep-water installation. To calculate these coefficients, a series of model tests of the drag coefficients of a typical subsea manifold with eight slots were carried out at Zhejiang University. A numerical simulation was performed using the computational fluid dynamics (CFD) method, and the

Ships operating in ice-covered waters may experience structural damage due to ice-induced loads. This can occur even though the ship structure is designed according to rules considering ice loading. The basis of these design rules can be empirical, e.g. measured loads from full-scale trials and observed damages or energy based, which is known as the Popov Method. The rules propose to apply the design

This paper is a sequel to the authors’ article on a full-scale fire testing to collapse of a steel stiffened plate structure without passive fire protection (PFP) under lateral patch loading (Paik JK, Ryu MG, He KH, Lee DH, Lee SY, Park DK, Thomase G. 2020. Full-scale fire testing to collapse of steel stiffened plate structures under lateral patch loading (Part 1) – without passive fire protection

The aim of this study is to investigate the impact crashworthiness of a floating offshore nuclear power plant hull structure in an aircraft strike; the hull has a double-sided design that includes ballasting with either sand or concrete. As a hazardous event associated with a terrorist attack, one of the unfavourable impact scenarios is adopted in which a Boeing 777 airplane strikes the hull structure

The transfer characteristic of the CT’s axial load is necessarily investigated for its safety operation. In this study, a mechanical model of the coupled tube systems is described using micro element method. To analyse the effects of ocean loads, an experimental downsized platform is built. A physical vibration exciter is used to simulate the SCR’s lateral vibration, and then the axial load and its

In the present work, the sloshing phenomenon in a rectangular tank with non-Newtonian Bingham fluid is modeled. The numerical method used is the Incompressible Smoothed particle Hydrodynamics (ISPH) method. In the present study, first, a proper algorithm has been developed for modeling the Bingham fluid with the free surface. The method is validated by the famous previous works and experimental results

As a type of Autonomous Underwater Vehicles (AUV), blended-wing-body underwater gliders (BWBUGs) have drawn much attention due to their unique performance advantages in long-distance navigation missions. Because the configuration is the direct component to influence the navigation efficiency, it is significant to perform shape optimisation of BWBUGs. In this paper, an optimisation framework is presented

Naval high speed light craft (HSLC) can be vulnerable to fatigue damage due to their lightweight scantlings and operation in sometimes harsh environments. Fatigue cracking can lead to costly repairs and reduction of operational availability. One fatigue analysis method is spectral fatigue analysis (SFA), which explicitly includes the operational profile and wave environment. However, typically, only

ABSTRACT A 4 degrees of freedom ship performance prediction model is used to compare wind-assisted ship propulsion technologies: the Flettner rotor, a wingsail and the DynaRig concept. An Aframax Oil Tanker on a route between Gabon and Canada is used in a case study to compare the three technologies using actual information for the voyage. The fuel savings for were calculated and they varied between

Previously the effect of configuration of containers as well as wind angle of attack on the wind resistance of a container ship was studied by using simple blocks to represent the containers. However, in field observations, the authors testified large geometric deformations in statistically significant numbers of containers. Using ANSYS CFX, the outer side of the stacking configuration is modelled

This paper investigates the computational methods for calculating the dynamic responses of a floating wind turbine. The mathematical procedures for a proposed new identification method for fitting a state space model to approximate the convolution term in the motion equation of the floating wind turbine have been specified, and these mathematical procedures have been executed in a stand-alone MATLAB

The periodic array of multiple articulated floating elastic plate acted upon by ocean waves is analysed considering Timoshenko-Mindlin plate theory. The floating elastic plate is placed periodically and is interconnected with vertical linear and flexural rotational springs which acts as an articulated joint. The hydroelastic behaviour of multiple articulated floating elastic plate is analysed based

This paper addresses the assessment of the structural integrity of a rudder horn built of different materials and in particular, the material quality effects on the structural design of a typical rudder horn of a conventional Panama-Kamsarmax size ship in relation to IACS requirements. The minimum scantlings of the rudder horn were established and compared for different steels permitted in IACS UR

The added mass is referred to as an extra mass of fluid accelerates with the body caused by body acceleration in the fluid. Surge added mass of ships is relatively low in comparison with their mass which does not have considerable influence on ship manoeuvrability. That is why less research have focused on the surge added mass. This research deals with the surge added mass of planing hulls by model

The influence of wavelength, wave steepness and bow rake angle (α) on the green water occurrence and peak pressure on a container ship deck is numerically investigated. Numerical simulations are performed using a commercial CFD solver, where a VOF method is employed to capture the free surface. The approach is validated using previously published experimental results. The time histories of the evolution

In recent years, oil and gas pipes and risers in deep sea reservoirs are required to have high resistance to collapse. This paper reports the comprehensive investigation of the residual stress distributions in a recently developed seam-welded offshore gas transmission riser of high-strength steel. Experimental hole drilling methods are applied to understand the residual stress distribution in the real

The aim of the present paper is to investigate the ultimate strength characteristics of as-built ultra-large containership hull structures under combined vertical bending and torsional moments with varying the ship size. The intelligent supersize finite element method (ISFEM) is employed for the ultimate hull girder strength analyses. A total of three as-built containerships carrying 9,300 TEU, 13

During the service life of the offshore pipelines, different failure mechanisms like external/internal sheath damage, fatigue damage, or corrosion may arise. Therefore, high operating costs need to be consumed to confirm the fitness of the pipeline system. This research deals with an enhanced Risk-Based Inspection (RBI) methodology to certify the integrity management of the pipeline system, a radical

The purpose of this paper is to elaborate the non-linear collapse of externally pressurized resin toroidal and cylindrical shells, along with a comparison between a toroid and cylinder. For this purpose, the collapse characteristics, critical loads, and imperfection sensitivities of volume equivalent shells were numerically evaluated for the first eigenmode imperfection. Furthermore, three nominally

Machine learning is an effective way to realise the condition monitoring of marine machinery. However, it is challenging to realise this purpose based on supervised learning in practice due to the lack of labelled data. To overcome this problem, we propose to use isolation forest to realise the decay detection of a marine gas turbine with normal data. Besides, we consider the impact of data contamination

Huge progress has been made in the design innovation for ultra-large container ships, instead of in cargo securing systems. The mechanical behaviour characteristics of the lashing bridge were studied statically and dynamically. Firstly, the static and dynamic characteristics of the prototype structure were obtained via finite element analysis. Then, the coupling effect between the lashing bridge and

ABSTRACT The study presents an investigation of Waves4Power’s WaveEL 3.0 wave energy converter (WEC). It was used as a reference for full-scale measurements of the mooring forces and buoy motions in a measurement campaign 2017 at an installation location off the coast of Runde in Norway. A numerical simulation model of the installation was developed in the DNV GL software SESAM. Unfortunately, the

In the present research, the three-dimensional (3D) time-domain hybrid Green function method is developed for simulating the coupled motions of two floating bodies with the side-by-side arrangement in waves. The fluid domain is decomposed into an inner and an outer domain by an imaginary control surface. Then, the Rankine source is adopted in the inner domain, while the transient time domain Green

Accidental events such as collision, grounding, and explosion in marine structures can cause plastic deformation and structural damage. Various fracture models based on different mechanical concepts have been proposed to predict damage extents involving ductile fracture. In this paper, some fracture models were evaluated: Maximum shear stress, Cockcroft-Latham, Johnson-Cook, Modified Mohr-Coulomb,

The intrinsic complexity of the flooding process on ships renders accurate quantification of the flooding risk a highly arduous task, particularly in the context of emergency management. This is especially true for large cruise vessels where convolution stems from innovative designs and complex internal subdivision resulting in a multitude of variables and their interdependencies. This augments the

The study presents numerical investigations on hydrodynamic quality of high-speed planing hull with spray rails and interceptor. Interceptors are blades which extend vertically downwards at the bottom near transom. The pressure distribution is the main cause for reduction in trim of the vessel. The interceptor has an effect on vessel resistance reduction which further result in more desirable trim

Use of high performance fibre ropes (HPFR) is attractive in subsea operations due to high strength and low weight making lifting operations in deep waters possible with practically no reduced lifting capacity. However, experiments show that HPFRs can cause higher loads on multilayer winch drums compared to steel wire ropes. This paper presents comparisons between experimental stress measurements and

This study proposes a procedure to determine the optimal design parameters and target reliability based on Life cycle cost (LCC) based analysis. An iterative design procedure is performed for different levels of reserve strength ratio (RSR), and LCC is calculated. A case study is carried out for installation of the bottom fixed jacket support structure for offshore wind turbines (OWT) system subjected

The float-over installation method has become the best solution to offshore heavy topsides installations due to its flexibility and low cost. Dynamically positioned vessels can accurately keep position and track the predefined path with the help of thrusters, which eliminate the rigid requirements on auxiliary tugboats andmooring system. A precise control strategy is of critical importance to ensure

ABSTRACT The Arctic is rapidly transforming into a navigable ocean because of global warming. Consequently, a large percentage of the sailing distance between Europe and Asia could be saved by alternatively sailing through the Arctic. However, taking Arctic routes is fraught with risks and additional costs due to sea ice. The major purpose of this study is to improve safety and fuel efficiency of Arctic

Failure threats in subsea pipelines are hard to inspect, but parameters influencing them are easier to observe. Hence, nowadays, Bayesian network models became more relevant, as the model can be updated with the sparse observations while considering the underlying uncertainty. This holds for failure threat assessment of subsea pipelines, specifically for a highly random corrosion mechanism, which has

Corrosion, fatigue and corrosion-fatigue cracking are the most pervasive types of structural problems experienced by ship structures. These damage modes, can potentially lead to unanticipated out of service time or catastrophic failure. Acoustic Emission is gaining ground as a complementary Structural Health Monitoring (SHM) technique, since it can offer real-time damage detection. Deep learning, on

This paper presents the impact of different geometrical parameters on the seakeeping of a trimaran in regular oblique waves. Experimental tests for eight different arrangements of outriggers were conducted for a range of wave frequencies where a constant wave heading, and wave height was maintained. It was found that the position of outriggers and the hull shape have significant impacts on dynamic

The paper presents experiments and finite-element simulations of welded 5083-H116 aluminium alloy panels, quasi-statically punched at the mid-span by a rigid hemispherical indenter, to examine their plastic deformation and fracture resistance. Four specimens are examined: one bare plate, one butt-welded plate and two stiffened plates. The effect of the welding and the influence of stiffeners on the

Collisions frequently occur at sea, leading to serious human injury, and damage to property and the environment. Furthermore, the increasing number of offshore platforms means that collisions between vessels and offshore structures are a frequent type of accident. Platforms are at a greater risk of collisions than ships, because they have no avoidance capability when operating. Recently, the expansion

To develop an equivalent device of the umbilical cable, in which the hydraulic transmission characteristics are the same as the real umbilical cable. Simulation and experimental methods were used to study the hydraulic transmission characteristics. Theoretical relations of hydraulic resistance, hydraulic capacitance, and hydraulic inductance were derived by using the similarity principle. Simulation

As a vital key part of the modern offshore wind energy industry, floating offshore wind turbines (FOWT) are built to generate green renewable energy. Robust prediction of extreme loads during FOWT operation is an important safety concern. In this paper, the FAST code has been used to analyse offshore wind turbine internal bending moments due to environmental hydrodynamic wave loads, acting on a specific

Stringent rules and regulations to reduce ship environmental footprint and continuous aim to improve the propulsion efficiency stimulate development of different technical solutions. Typical technical solution that reduces ship total power needs (particularly for the propulsion) is the Energy saving device (ESD), i.e. special hydrodynamic appendage installed on the ship aft body. In this paper, the

Sampling method is an effective tool for building approximated models, which can improve the efficiency of hull form optimisation. A dynamic sampling method (DSM) is introduced herein to improve the accuracy and efficiency of the approximated model by considering the influences of sample quality measures in both input and output parameter spaces. The DSM uses leave-one-out to obtain an estimate of

In this article the loads and dynamic responses of an offshore wind turbine (OWT) operating in a nonlinear multidirectional mixed sea have been rigorously investigated. It has been demonstrated that nonlinearly simulated realistic waves with bottom effects should be utilised as inputs in the stochastic time domain simulation in order to design an un-conservative support structure for the offshore wind

In this study, the roll damping coefficients of a high-speed planing hull are calculated numerically in order to show the effects of forward speed, roll amplitude and oscillation frequency. Forced roll simulations are carried out to calculate roll damping coefficients. The numerical study is performed at high forward speeds by using a commercial URANS (Unsteady Reynolds-averaged Navier–Stokes) solver

Dynamic environmental loads, such as winds and waves, make the stability of offshore structures at high risk, requiring reliable yet efficient control elements to ensure the stability of such structures under lateral loads. Among the variety of control elements that have been developed to enhance the stability of a structure, shape memory alloy (SMA)-based control elements are promising as they are

Modern ice breakers, using new technology, are now able to create channels through level ice and clean out the ice fragments, resulting in an open-water channel between two large ice sheets. Whilst this negates the potential resistance increase on a following vessel due to interacting with the broken ice pieces, the ship performance will still be influenced by the two large ice sheets on either side

This work deals with the investigation of granules as crash absorber in ship building. Using expanded glass granules, the increase in energy dissipation during a ship collision is examined. For this purpose, we investigate a simplified side hull structure. Four experiments are conducted. On the one hand, we carry out reference experiments without granular material. On the other hand, we investigate

Taking NREL 5 MW large offshore wind turbine as a research object, a theoretical model considering geometrical nonlinearity is established, and the dynamic response analysis is carried out. Besides, the blade scaled model is processed and used in the wind tunnel test. The numerical results show that the response values of displacement and Mises stress for the blade, as well as the increment of displacement

The study focuses on the analysis of the added resistance of a catamaran advancing both in regular waves and in a seaway. The numerical simulation has been carried out within the framework of potential flow theory by using a three dimensional, linear, Rankine source-based Boundary Element Method (BEM) and a Near-Field approach based on pressure integration for the first-order motions and the second-order

It is well recognised that footprints are formed during the spudcan insertion process, which can have a negative impact on adjacent pile foundations.This research presents a simplified three-dimensional finite element model to analyse the effect of footprints on the vertical bearing capacity of adjacent piles in clay. The soil parameters around the footprint were obtained via a comparative analysis

The U-type stiffener is widely used in hatch cover design for cargo holds due to its easier fabrication, maintenance and painting. However, its ultimate strength evaluation method under axial compression is still unclear. The existing formula for ultimate strength evaluation of stiffened panel is not applicable to U-type stiffened panels of hatch cover with thinner deck plate, wider plate breadth between

In an age where sailing boats are losing their reputation of slow-moving vehicles, and where technologies are developing at explosive rhythm, the scantling criteria are deeply changing and naval architects face new challenges. Beside a literature review on sailing yacht appendages design, the state of the art of the methods for fluid-elastic phenomena prediction is presented. To face the problem of

Boundary element method incorporated with free-surface Green’s function (FSGF) is commonly used for radiation and diffraction problems of a floating body. In the solution of the boundary integral equation, it is important to obtain the integral of FSGF over panels. However, most of the research studies focus on the numerical calculation of FSGF. In the present paper, the spatial distribution of FSGF

The concept of Modular Floating Structures (MFS) presents a unique alternative to increase the available land resources in the adjacent marine environment of coastal cities. It offers a sustainable technological adaptation that can help mitigate overdevelopment and urban growth limitations. This study examines the comfort range of a suburban offshore MFS module, by using a novel methodology that reconciles