Showing papers in "Ocean Engineering in 2022"

TL;DR: In this paper , the design and dynamic analysis of a multi-column tension leg platform floating offshore wind turbine (TLP FOWT) with broken tendons was presented. But the tendon failure affected the turbine's heave, pitch and roll motions, hence its natural frequencies, and the tension in the non-broken tendons.

TL;DR: In this article , the authors proposed an FMEA-BN model to determine the inspection and opportunistic maintenance strategies of floating offshore wind turbines, where the failure probabilities of items of a floating turbine are first updated by the BN sub-model, in which, various operation scenarios are considered.

TL;DR: In this paper , the authors investigated the effect of construction disturbance on the horizontal dynamic response of pile embedded in unsaturated soil when the pile is subjected to time-harmonic horizontal loading and vertical loading.

TL;DR: In this paper , a combined concept consisting of a 5MW braceless semisubmersible floating offshore wind turbine (FOWT) and a torus-type wave energy converter (WEC) is proposed and investigated for four different examined WEC shapes.

TL;DR: In this paper , the capability of Artificial Neural Network (ANN), Adaptive Neuro-Fuzzy Inference System (ANFIS), M5P, and Random Forest (RF) soft-computing approaches for the prediction of wave height over Persian Gulf was examined.

TL;DR: In this paper , a robust fractional-order proportional-integral-derivative (FOPID) controller design for an AUV yaw control system is proposed.

TL;DR: In this paper , a review explores the path planning algorithms of autonomous maritime vehicles and their collision regulation relevance in order to reveal how the research community handles this issue, and the relevant findings point out that there are still many traffic rules to be dealt with by path-planning algorithms.

TL;DR: In this article , an AUV agent is trained with deep deterministic policy gradient (DDPG) algorithm in a simulation environment, and three-degree-of-freedom posture control of the AUV at a constant speed, fixed roll, variable pitch, and variable yaw, is successfully achieved.

TL;DR: In this article , the authors studied 22 tide gauge waveforms, eight DART (Deep-ocean Assessment and Reporting of Tsunamis) records, eight air pressure time series, apply spectral analysis, and conduct numerical modelling to develop a source model.

TL;DR: In this paper , a novel hybrid neural network scheme based on convolutional neural network (CNN) and long short-term memory (LSTM) is proposed for multi-step wind speed prediction.

TL;DR: In this article , a vector form intrinsic finite element (VFIFE) method is proposed for modeling floating offshore wind turbines (FOWTs) based on the VFIFE method, and a dynamic and flexible model of the mooring system is included, and their axial extension, inertia, and hydrodynamic loads are considered.

TL;DR: In this article , a Monte Carlo simulation procedure is developed to select the optimum location of wind farms by using major decision criteria and applying subjective judgments from decision-makers, which is applied to offshore wind farms located in Spain, and the most appropriate locations for turbine positioning are ranked.

TL;DR: In this paper , a series of numerical simulations on the submarine slide-pipeline interaction at Reynolds numbers ranging from 0.36 to 287 via a computational fluid dynamics (CFD) method is presented.

TL;DR: In this article , an experimental set-up of laboratory offshore wind turbines and loadings are developed and used to perform long term model tests under High Cycle Application loading in sand. But, the authors admit that commonly used fixed amplitude cyclic loads may underestimate the change of natural frequencies and/or tilt by up to 20%, with 2% large loads contributing up to 50% of change.

TL;DR: Artificial Neural Networks (ANNs) were firstly used to model ocean engineering problems in the decade of 1990s as discussed by the authors , and since then, this soft-modeling technique has proved several advantages against traditional approaches.

TL;DR: In this paper , the development and trend of MASS are collected, and main research institutions are analyzed based on MASS experimental projects and publications, and the main topics involved in human-machine cooperative navigation are presented.

TL;DR: In this article , the effect of pipeline surface roughness on impact forces on suspended and laid-on-seabed pipelines caused by mudflows is quantified. And a standard chart methodology considering pipeline roughness to estimate peak impact forces is established, which provides a basis for the risk assessment of the whole life cycle of submarine pipelines.

TL;DR: In this article , a synchronous experimental system including the test pump, high-speed camera and sensors is built to measure cavitation and vibration of the pump under steady state and fast start-up process with different accelerations of rotational speed.

TL;DR: In this article , a physics-informed neural network (PINN) is used to solve the inverse water wave problem. But the authors consider strongly nonlinear and weakly dispersive surface water waves governed by equations of Boussinesq type, known as the Serre-Green-Naghdi system.

TL;DR: In this paper , numerical investigations on a free-floating Catenary Anchor Leg Moorings (CALM) buoy were carried out and an Orcaflex-coupled model of the CALM buoy system with submarine hoses in Lazy-S configuration was presented.

TL;DR: A comprehensive review of the maritime collaborative collision avoidance studies can be found in this article , where the authors identified gaps ranging from assumptions on communication capabilities and considerations related to non-cooperative actors to cybersecurity concerns and suggested how to address these gaps by taking advantage of e-navigation concepts and technologies.

TL;DR: In this paper , the root causes of ship-to-ship collisions were determined statistically, using Fault Tree Analysis (FTA) and Multiple Correspondence Analysis (MCA), and it was determined that maneuvering and perception errors were the most effective factors in collision accidents.

TL;DR: In this article , an uninterrupted collision-free path planning system for ocean sampling missions is presented, which facilitates the operational performance of multiple unmanned surface vehicles (USVs) in an ocean sampling mission by integrating B-spline data frame and particle swarm optimization (PSO)-based solver engine.

TL;DR: In this paper , a safe Lyapunov boundary deep deterministic policy gradient (SLDDPG) algorithm is presented for the USV interception mission, which can fast converge to the feasible solution subject to safety constraints.

TL;DR: In this paper , a detailed literature review of existing hybrid aerial vehicles characterizing their designs, and describes the current state of the art in methodologies to enable cross-domain mobility of HAUVs is presented.

TL;DR: In this article , the authors conducted a literature review on ship fuel consumption (SFC) models and concluded that the current SFC models can be classified into three types: white, black, and grey boxes.

TL;DR: In this article , a fixed-time extended state observer (FxTESO) is set up to estimate the unknown states and the lumped disturbances (including external disturbances and model uncertainties).

TL;DR: In this article , a path planning model based on the safety potential field theory is proposed for inland ships from the perspective of navigation risk, and the minimum navigation risk points on each cross section, which is perpendicular to the navigation direction, are selected to formulate the optimal path.

TL;DR: In this paper , a condition-based maintenance strategy is proposed for a large-sized container ship, based on an Artificial Neural Network (ANN) to analyze the performance of the engine.

TL;DR: In this paper , a 3D coupled discrete continuum model was performed to reveal the interaction mechanism between different pile foundations and the surrounding soil, and the influence of pile stiffness and hybrid foundation type on the lateral response was analyzed.