Carlos Guedes Soares

University of Lisbon | UL · Centre for Marine Technology and Ocean Engineering (CENTEC)

A cost and financial evaluation model is proposed for floating wind farm designs. The model evaluates the cost of the offshore farms depending on the required capacity, technical aspects, and technology implemented, among other aspects. The costs involved in the different phases of the farm construction are studied. The main equations developed for...

The hardware-in-the-loop technique is a hybrid co-simulation approach that joins real physical and virtual components. The real components may be the power take-off while the virtual ones the numerical models of sea wave and wave energy converter hydrodynamics. This simulation approach has been published with some regularity, however a review of th...

This paper investigates the vertical bending, horizontal bending, and torsion loads on an ultra-large container ship in high sea states and different Froude numbers using a strip theory-based 2D time domain code. The numerical solver is based on a potential flow theory and a body nonlinear approach. The hydrody-namic coefficients are estimated usin...

A new wave energy converter is proposed in this paper, consisting of three split heave point absorbers, combined with a taut-moored floating turbine. It is adapted to the waves in the China Sea area, which are characterized by short periods and small amplitudes. Based on a series of physical model tests in regular, irregular, and extreme waves, the...

In present study, a sensitivity analysis of hydrodynamic interaction for two ships maneuvering in calm water is performed by an indirect method. A 3 degree of freedom mathematical model (MMG) is used to predict ship motion in the horizontal plane, the hydrodynamic interaction forces are predicted by a code based on potential flow theory where the v...

ABSTRACT: Several collision risk indicators have been proposed for collision risk assessment and decision-making models for preventing ship accidents. The present study aims at characterising the collision risk indicators in ship-ship encounter scenarios by analysing the ship collision avoidance behaviour. First, evasive manoeuvres from ship trajec...

This study conducts extraction and analysis of AIS data of the traffic flow around the Leixões port. The his-torical traffic flow distribution of different types of vessels provides a statistical basis for the historical route distribution parameters of Leixões port by primarily utilizing the historical data of maritime traffic flow. According to t...

A series of experimental tests are conducted to investigate the performance of a newly proposed multi-layered flexible membrane breakwater under regular and irregular waves in a two-dimensional wave flume. The effect of various parameters, such as edge conditions, spring stiffness of mooring lines, wave height, wave period, breakwater height, subme...

This paper presents an integrated framework for reliability-based design of deep-water vertical subsea separators using a novel collapse strength model. An analytical model for collapse strength prediction of a vertical subsea separator subjected to external pressure is proposed based on around 500 numerical simulations covering different geometrie...

A review presents the state-of-the-art path-following control systems for maritime autonomous surface ships, where the special focus is placed on the guidance subsystem and control subsystem. The path following control system is one of the basic requirements for autonomous ships since it guarantees that the ship can track the predefined path with s...

A fully nonlinear hydroelastic numerical method is proposed for the fluid-structure interactions of elastic ships. The boundary value problem is solved by the three-dimensional boundary element method. To simulate the instantaneous evolution on the free surface, an effective mesh optimization solution consisting of the local coordinate system and a...

A series of experimental model tests are conducted to investigate the performance of a combined membrane breakwater consisting of horizontal and vertical flexible membranes against regular and irregular incident waves. A dimensional analysis is carried out to determine the dimensionless parameters used to study the performance of the breakwater. Th...

This paper presents the performance of a new, floating, mono-hull wind turbine installation vessel (Nordic Wind) in the installation process. The vessel can transport pre-assembled wind turbines from the marshalling port to the offshore installation site. Each assembled turbine will be positioned over the pre-installed floating spar structure. The...

The paper describes the continuation of studies carried out earlier in the application of system identification to the estimation of parameters of ship manoeuvring mathematical models. A new version of a versatile identification algorithm based on various metrics and global optimization schemes is described. The algorithm is tested on artificial tr...

A subsea pipeline (also known as an offshore pipeline or submarine pipeline) is a pipeline that is laid on the seabed or inside a specially constructed trench [...]

This chapter reviews the state-of-the-art methods and procedures for the reliability and maintainability of floating offshore wind turbines. First, a new failure identification and critical failure determination schedule is introduced, according to which failure prevention actions are determined. Subsequently, failure rate and reliability analysis...

This study presents the adaptation of a torus shaped prime mover of a wave energy converter to an onshore or nearshore fixed platform by a hinged arm, with the objective of providing more favorable conditions for device survivability at extreme sea state. An optimization code is developed to obtain the best prime mover and arm geometries, as well a...

This paper addresses the selection of an optimal port for components storing and assembly of offshore wind components so as to reduce the total transportation cost, as the hub port is an important supply-chain issue that affects the installation of floating wind parks. An integrated multi-Criteria Decision method is presented for the port selection...

A new uncertainty quantifier is presented for linear transfer functions of wave-induced ship motions and loads obtained by various seakeeping codes. The numerical simulations are conducted for the high-speed Flokstra container ship in regular waves at various heading angles, and the results are compared with existing experimental data. The study em...

A decision support system is proposed for the condition-based maintenance of ship machinery systems based on the adaptive neuro-fuzzy inference system (ANFIS) approach. A case study is conducted for a container ship's main diesel engine. Within the scope of the methodology, the main engine power is predicted based on exhaust gas outlet temperatures...

This paper presents a comprehensive review of the current regulations and the various technologies as well as the decision support methods for each technology the maritime industry considers to ensure the fleet's sustainability. It covers the period between 2010 and 2022, emphasizing the last four years. It shows the impact of each technology on th...

Ships in service feature surfaces that exhibit biofouling, which alters the hydrodynamics of the vessels, thus affecting their normal displacement and significantly increasing their fuel consumption. The application of three types of ceramic coatings as ecological, effective and durable alternatives to commercial silicone-based marine coatings is i...

This paper reviews the importance of uncertainties in hull girder loads influenced by flexible fluid structure interactions. The focus is on developments in the field of hydroelastic modelling, simulation and model tests of practical relevance to the prediction hull girder wave load predictions and their validation. It is concluded that whereas hyd...

An assessment is made of the stress distribution and the hydrodynamic response of the preliminary structural design of the tension leg platform of a 10 MW wind turbine. The platform supporting a 10 MW turbine is modelled and analysed by the finite element method. The stress distribution of the platform is determined in still water with the turbine...

The stress concentration factors (SCFs) in uniplanar fibre-reinforced polymer (FRP) DKT joints are calculated under five axial loading conditions to determine the maximum SCFs. To this end, 108 finite element models of reinforced DKT joints with different FRPs and geometrical parameters are analysed. Available experimental data and formulas are use...

Ship hydrodynamics and dynamics is a rather old, traditional branch of applied mechanics and also of naval architecture [...]

This paper proposes an innovative approach to evaluate and enhance the ship's energy efficiency using a machine learning (ML) technique. A methodology is proposed combining an engine optimization model and a data-driven approach to monitor and predict the performance of the ship along the route. The starting point is a dataset of noon report data c...

An experimental study is presented on the non-Gaussian statistics of random unidirectional laboratory wave fields described by JONSWAP spectra. Relationships between statistical parameters indicative of the occurrence of large-amplitude waves are discussed in the context of the initial steepness of the waves combined with the effect of spectral pea...

This paper presents a comprehensive experimental study on the effect of extreme waves on a LNG carrier. The LNG carrier model was equipped with a variety of sensors to measure motions, green water height on deck as well as local and global loads. Experiments in transient wave packets provided the general performance in waves in terms of response am...

This paper presents a review of the different methods and techniques used to optimize ship hulls over the last six years (2017–2022). This review shows the different percentages of reduction in ship resistance, and thus in the fuel consumption, to improve ships’ energy efficiency, towards achieving the goal of maritime decarbonization. Operational...

This study presents the state-of-art and future trends of the maintenance approaches to ship machinery systems. A systematic review process is conducted to identify relevant literature. Firstly, literature is examined by bibliometric analyses based on the determination of the distribution of papers by years, the top authors, papers, journals, and o...

The effects of hull and propeller roughness are presented over ten years of operation on ship performance. The developed model used in this study is a combination of NavCad and Matlab to perform the resistance and propulsion computations of the selected ship as well as the processing of input and output data. By considering the ship hull, the engin...

An analytical model of oblique wave interaction with a moored floating flexible structure based on the Timoshenko-Mindlin beam theory is developed under the assumption of small amplitude wave theory and structural response. Theoretical solutions on the deflection of the structure and reflection and transmission coefficients are obtained by applying...

In the present paper, the interaction between a large freely floating articulated structure and regular waves is investigated by model tests based on the computer vision target tracking approach. The detailed description of the experimental setup and measurement techniques are presented. The design parameters and the number of plates adopted by Bis...

With the expansion of the Arctic route, the safety of ship crossing the area in light of the low temperature and ice has become of focus, especially with regards to the ship’s structure. The mechanical properties of the material making up the ship’s structure may not be suitable for the Arctic environment. A series of quasi-static and dynamic tests...

Mixed-integer linear programming is adopted to translate the routing of service operation vessels that support the logistic aspects of the maintenance of offshore floating wind farms into mathematical language. The models attempt to help the decision-makers by providing quantified tools to screen out the optimal planning for preventive maintenance....

This paper focuses on the buckle propagation pressure of a pipe-in-pipe system under uniform external pressure. After the validation of the finite element model used in this research, several effects were studied. At first, the effects of the initial imperfection of the inner pipe, including the ovality and eccentricity, were checked out. Second, t...

The wave model WAVEWATCHIII is used to produce wave information, until the end of the 21st century, covering all ocean areas. Global wind and ice-cover climate data from a total of 120 years are used as input for the wave model. The period is divided into four 30-year slices, where the first (1980-2009) represents the recent past, the second (2010-...

A fracture mechanics-based fatigue reliability analysis of a submarine pipeline is investigated using the Bayesian approach. The proposed framework enables the estimation of the reliability level of submarine pipelines based on limited experimental data. Bayesian updating method and Markov Chain Monte Carlo simulation are used to estimate the poste...

An analytical model of a current load’s interaction with a moored floating flexible structure based on the Timoshenko–Mindlin beam theory is developed under the assumption of small amplitude wave theory and the structural response. Theoretical solutions on the displacement of the structure, reflection, and transmission coefficients are obtained by...

In the present study, the effects of different loadings, types and materials of fibre reinforced polymers on the stress distributions in uniplanar KT joint reinforced with fibre reinforced polymer are predicted. Finite element models reinforced with different numbers of layers of fibre polymers with different geometrical parameters are produced and...

Sensitivity analysis is applied to ship manoeuvring mathematical models as a means of dealing with model uncertainties, and often leads to model simplifications. A rather standard 3DOF manoeuvring model was tuned with the available results of full-scale trials of a naval combatant and was further used as the reference model for sensitivity analysis...

The paper assesses the contribution of specific Risk Influencing Factors (RIFs) towards the occurrence of ship collision accidents. The approach adopted is inspired by the Cox proportional hazard regression model and combines a Bayesian rule and the least-squares method to assess the influence of risk factors on the collision probability based on h...

Time series of wave-induced ship responses are analysed by the Hilbert-Huang Transform (HHT) method. The results of the analysis of numerically simulated motions and loads on a chemical tanker in head waves are compared with the analysis of experimental data from laboratory model tests. The Empirical Mode Decomposition, which is a first part of HHT...

The paper presents a review of the developments in ship collision analysis over the last 10 years and the challenges to an Accidental Limit State (ALS) design method of ships based on collisions. It aims to discuss the technical difficulties in finite element analysis, especially the mesh-dependent material failure criterion, the accuracy of the an...

https://www.mdpi.com/journal/jmse/special_issues/668NU31H8V

A review is provided of various approaches that have been adopted recently to assess the fatigue of ships and offshore structures. The relevant fatigue loading is reviewed first, focusing on the successive loading and unloading of the cargo and the transient loadings. The factors influencing fatigue strength are discussed, including the geometrical...

The primary objective of the present literature review is to provide a constructive and systematical discussion based on the relevant development, unsolved issues, gaps, and misconceptions in the literature regarding the fields of study that are building blocks of artificial intelligence-aided life extension assessment for offshore wind turbine sup...

Recent years have seen the rapid development of autonomous ships. The maritime industry is currently experiencing a disruptive change in technology through the increased development of advanced autonomy technologies leading to Maritime Autonomous Surface Ships (MASS), Unmanned Surface Vessels (USVs), Autonomous Underwater Vehicles (AUVs), and under...

This paper assesses the uncertainty of the partial safety factors for the design of corroded pipelines against burst failure due to the variability associated with the strength model selection. First, 10 calibrated burst pressure prediction models for corroded pipelines are adopted and duly categorised under low-, medium- and high-grade steel class...

A novel procedure is introduced to optimise floating turbines' placement in a wind farm. In the approach, the ‘Weighted Product Model (WPM)'is used, which is a Multi-Criteria Decision Method (MCDM). The turbine position is made by the mean of technical, economic, and environmental criteria. Moreover, experts' knowledge is introduced in the framewor...

This work aims to determine the critical response of hydrogen flexible pipes, which are currently developed in industry to transport high-pressure compressed hydrogen. A reinforced thermoplastic pipe model subjected to internal pressure is proposed. A nonlinear finite element composite pipe model is generated to predict the structural behaviour und...

A numerical study is presented on the hydrodynamic response prediction of a tension leg platform with a 10MW floating wind turbine using a potential flow based solution. The objective is to evaluate the validity of the adopted numerical model to estimate the response of the tension leg platform. The numerical simulations are carried out in the time...

A simplified two-dimensional mathematical model of wave interaction with a moored flexible floating rectangular beam based on the Timoshenko-Mindlin-Beam theory in finite water depth is presented. The theoretical solution of the aforesaid model is obtained by employing the matching technique along with the orthogonal mode-coupling relation in finit...

A 3D mathematical model associated with wave interaction with a horizontal floating flexible membrane supported by linear springs under linearized small-amplitude wave theory is presented. The dispersion relation is derived based on Green’s function technique and it is utilized in the solution by employing the velocity decomposition method. The lev...

This paper presents the uncertainty modelling of experimental results for a physical model of a tanker moored to a terminal inside a port. The physical model was built for an oil terminal at the port of Leixões in Portugal. The model incorporates the new modified port layout, as well as a future 300 m extension of the port outer north breakwater to...

A series of 1:40 model tests are carried out to study the dynamic responses of a point absorber moored by three taut nylon ropes under irregular wave conditions. The experimental results are applied to calibrate a numerical model, and then the calibrated numerical model is applied to study the influence of pretension, mooring axial stiffness, curre...

An approach is developed for floating wind farm installation by creating a model that allows the planning of the main logistics and installation aspects of a floating wind farm. The method aims to preserve the coherency between logistic methods and project performance, as floating wind farm installation is a complex problem, due to the number of co...

Artificial neural networks are applied to model the manoeuvrability characteristics of a ship based on empirical information acquired from experiments with a scaled model. This work aims to evaluate the performance of the proposed method of training the artificial neural network model even with a very small quantity of noisy data. The data used for...

In this paper, a propeller optimisation model is presented to find the optimum propeller geometry and the gearbox ratio for different propeller shaft angles while minimizing the amount of fuel consumed at a given speed and complying with the proposed constraints’ limitations. The developed model couples several simulation software where the applica...

The paper studies and compares the manoeuvring capabilities of an appended KRISO Container Ship (KCS) hull model in both open and restricted waters. The KCS hull model with a static rudder and body force model-based propeller is simulated using the open-source computational fluid dynamics toolkit OpenFOAM. Initially, open water simulations are perf...