References of "Rigo, Philippe"
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See detailUpdating Failure Probability Of A Welded Joint In Offshore Wind Turbine Substructures
Mai, Anh Quang ULg; Sørensen, John D.; Rigo, Philippe ULg

in The 35th International Conference on Ocean, Offshore and Arctic Engineering (OMAE) (2016, June)

For offshore wind turbines, the support structure contributes with a significant part to the Levelized Cost Of Energy (LCOE). LCOE is the total cost to build and operate a whole offshore wind turbine ... [more ▼]

For offshore wind turbines, the support structure contributes with a significant part to the Levelized Cost Of Energy (LCOE). LCOE is the total cost to build and operate a whole offshore wind turbine structure over its lifetime divided by the total energy output of the wind turbine over that lifetime. That total expected cost of operation & maintenance may be lowered by application of reliability- and risk-based maintenance strategies and updating of the reliability based on e.g. inspections performed during the design lifetime. Updating the reliability (or alternatively the failure probability) of a welded joint can theoretically be done using Bayesian updating. However, for tubular joints in offshore wind turbine substructure when considering a two dimensional crack growth and a failure criterion combined brittle fracture and material strength, the updating is quite complex due to the wind turbine loading obtained during operation. This paper considers how the reliability (or the probability of failure) of welded steel details can be updated in the case where the fatigue failure is modelled by a fracture mechanics approach and a Failure Assessment Diagram (FAD) is used to define a limit state equation. Besides, it is shown how the probability of failure of fatigue critical joints can be updated for various inspection scenarios. A two dimensional bi-linear model is considered for the crack growth. Calculation of the crack depth and the crack length are coupled. The stress intensity factor is calculated following the sophisticated procedure in BS 7910:2005. The initial crack size, the yield and ultimate strengths of steel, the fracture toughness, the stress intensity factor, and the stress-ranges are considered as uncertain and modelled by random variables. The probability of detection is used to account for uncertainty in crack inspections. By using Monte Carlo simulations, stress-range histories are generated randomly and together with the calculated stress intensity factors used to check the limit state condition using the FAD approach. The probability of failure updating is done for three inspection scenarios: No crack detected; Crack detected and repaired; Crack detected but not repaired. The paper presents illustrative results for offshore wind applications for the three scenarios, including comparisons of application of the FAD approach for modelling the limit state equation with a ‘conventional’ approach where it is assumed that failure happens when crack-depth reaches the plate thickness or the stress intensity factor is equal to or larger than the fracture toughness of the material. Finally, it is discussed how application of the updating procedure can be used for inspection planning for offshore wind turbine support structures, and thus also for reducing the required safety factors at the design stage. [less ▲]

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See detailWeather Down Time Analysis for Offshore Wind Farm Installations
Muhabie, Yohannes Tekle ULg; Petcu, Cristian; Rigo, Philippe ULg et al

in PIANC Yearbook 2015 (2016)

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See detailUne analyse dynamique des interactions entre acteurs portuaires et leurs effets sur l’efficience d’un port pétrolier
Belaid, Emna ULg; Rigo, Philippe ULg; Cools, Mario ULg

in Recueil des articles des 34èmes Rencontres Universitaires de Génie Civil de l'AUGC (2016)

The port is a heterogeneous entity which includes a set of actors whose objectives are sometimes contradictory. The analysis of their interactions allows us to understand the mechanism that governs the ... [more ▼]

The port is a heterogeneous entity which includes a set of actors whose objectives are sometimes contradictory. The analysis of their interactions allows us to understand the mechanism that governs the port management. This mechanism influences the port performance. In this article, we analyze port efficiency as a dynamic model. The latter is based on a framework established by a systemic analysis. From the simulations performed, it may be concluded that the parameters "loading rate" and "Connector dimension" are the most important parameters. Investment in new facilities for the port of La Skhira (Sfax, Tunisia) is our main recommendation. [less ▲]

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See detailShip collision on offshore wind turbines
Bela, Andreea ULg; Pire, Timothée ULg; Buldgen, Loïc ULg et al

in PIANC Yearbook 2015 (2016)

In a context of development of renewable energies, large offshore wind farms are being built close to traffic lanes and collision risk analysis on supporting structures is becoming a major concern. The ... [more ▼]

In a context of development of renewable energies, large offshore wind farms are being built close to traffic lanes and collision risk analysis on supporting structures is becoming a major concern. The aim of this paper is to present an overview on the ship – Offshore Wind Turbine (OWT) collision events. The behaviour of the OWTs structure with monopile and jacket foundations is investigated by means of numerical simulations. Furthermore, an analytical approach is presented for assessing the crashworthiness of the jacket foundation. [less ▲]

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See detailBi-objective Road and Pipe Network Design for Crude Oil Transport in the Sfax Region in Tunisia
Belaid, Emna ULg; Limbourg, Sabine ULg; Mostert, Martine ULg et al

in Procedia Engineering (2016), 142

In this paper, we examine a bi-objective road and pipe network design for crude oil transport in the Sfax region in Tunisia. In particular, we search for the minimum spanning trees (MST) that connect the ... [more ▼]

In this paper, we examine a bi-objective road and pipe network design for crude oil transport in the Sfax region in Tunisia. In particular, we search for the minimum spanning trees (MST) that connect the different oil fields with the port of La Skhirra. In the determination of the minimum spanning trees, two objectives are taken into account, i.e. accident risk and construction costs. By using an improved ɛ-constraint resolution technique, the Pareto optimal combinations of risk and cost are found. Results indicate that the network solutions by pipe outperform the solutions by road. When the minimum spanning trees for the two extremes on the Pareto curves, i.e. the cost minimum and risk minimum, are compared, one could note considerable differences in the links that form the MST. This implies that policy makers have an important role in deliberating between costs and risks. [less ▲]

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See detailAnalytical developments to assess the crashworthiness of an offshore wind turbine jacket impacted by a ship
Pire, Timothée ULg; Le Sourne, Hervé; Buldgen, Loïc ULg et al

Poster (2015, December 10)

As the number of offshore wind farms is constantly increasing, impacts between ships and wind turbines is becoming a major concern. Nowadays, design offices use finite elements simulations to assess the ... [more ▼]

As the number of offshore wind farms is constantly increasing, impacts between ships and wind turbines is becoming a major concern. Nowadays, design offices use finite elements simulations to assess the crashworthiness of offshore supporting structures, which give accurate results but is time demanding. There is therefore a need for a faster method, especially during the pre-design stage. The purpose of this research is to develop analytical formulations, based on the so-called continuous elements method in order to compute the resistance of offshore wind turbine jackets when submitted to an impact. [less ▲]

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See detailOrganic Rankine cycles systems for waste heat recovery in marine applications
Bellolio Domke, Sebastian Andres ULg; Lemort, Vincent ULg; Rigo, Philippe ULg

Scientific conference (2015, November 26)

In marine applications powered by internal combustion engines, a considerable amount of the energy contained in fuel is wasted through thermal losses. Additionally, as the years go by, new and more severe ... [more ▼]

In marine applications powered by internal combustion engines, a considerable amount of the energy contained in fuel is wasted through thermal losses. Additionally, as the years go by, new and more severe standards and regulations are imposed to the maritime industry. Despite of the traditional use of the waste heat recovery systems in ships, in order to meet new emissions demands, the research towards less traditional ways to reduce vessels emissions has been pushed. Nowadays the use of Organic Rankine cycles (ORC) seems to be a very promising solution to increase the global efficiency in maritime applications by converting the vessel’s thermal losses into useful work. Even if ORC’s have been studied during the last decades, it is only in the recent years that the maritime industry has drawn its attention towards these systems. In the first part of this paper, a state of the art of ORC in marine applications is performed. Then, the use of an ORC over traditional waste heat recovery methods (steam Rankine cycles) used in ships is discussed. Finally, a thermodynamic steady-state model of an ORC is coupled to a vessel ICE to estimate the improvements in energy efficiency that could be achieved by implementing an ORC in a vessel. [less ▲]

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See detailImproving the Installation of Offshore Wind Farms by the use of Discrete Event Simulation
Muhabie, Yohannes Tekle ULg; Caprace, Jean-David ULg; Petcu, Cristian ULg et al

in Improving the Installation of Offshore Wind Farms by the use of Discrete Event Simulation (2015, November)

The offshore wind energy development is highly affected by the condition of the weather at sea. Hence, it demands a well-organized planning of the overall process starting from the producers’ sites until ... [more ▼]

The offshore wind energy development is highly affected by the condition of the weather at sea. Hence, it demands a well-organized planning of the overall process starting from the producers’ sites until the offshore site where the turbines will finally be installed. The planning phase can be supported with the help of Discrete Event Simulation (DES) where weather restrictions, distance matrix, vessel characteristics and assembly scenarios are taken into account. The purpose of this paper is to simulate the overall transport, assembly and installation of the wind turbine components at sea. The analysis is carried out through DES considering both the real historical weather data (wind speed and wave height) and probabilistic approach. Results of the study, applied to the real Offshore Wind Farm (OWF) configuration, are showing a good agreement between the two proposed models. The results point out that the probabilistic approach is highly affected by the semi-random numbers used to model the stochastic behavior of the input variable so that several iterations (200 to 400) are required to reach the convergence of the simulation outputs. We suggest that seasonality of the outputs of both models are preserved, i.e. the variation of the results depending on the variation of the weather along the year. These findings provide a new framework to address risks and uncertainties in OWF installations. [less ▲]

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See detailPresentation of a simplified method for the crashworthiness of offshore wind turbine jackets
Pire, Timothée ULg; Le Sourne, Hervé; Buldgen, Loïc ULg et al

Conference (2015, October 13)

More and more offshore wind farms will be built in a near future and it is mandatory to perform for every new project a collision risk analysis. Actually, this is done by using finite elements software ... [more ▼]

More and more offshore wind farms will be built in a near future and it is mandatory to perform for every new project a collision risk analysis. Actually, this is done by using finite elements software, which is time consuming and not suitable for pre-design stage. The presentation show analytical developments performed in order to assess the crashworthiness of an offshore wind turbine jacket quickly. [less ▲]

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See detailSimplified analytical methods to analyze lock gates submitted to ship collisions and earthquakes
Buldgen, Loïc ULg; Bela, Andreea ULg; Rigo, Philippe ULg

in Mathematical Modelling in Civil Engineering (2015), 11

This paper presents two simplified analytical methods to analyze lock gates submitted to two different accidental loads. The case of an impact involving a vessel is first investigated. In this situation ... [more ▼]

This paper presents two simplified analytical methods to analyze lock gates submitted to two different accidental loads. The case of an impact involving a vessel is first investigated. In this situation, the resistance of the struck gate is evaluated by assuming a local and a global deforming mode. The super-element method is used in the first case, while an equivalent beam model is simultaneously introduced to capture the overall bending motion of the structure. The second accidental load considered in this paper is the seismic action, for which an analytical method is presented to evaluate the total hydrodynamic pressure applied on a lock gate during earthquake, due due account being taken of the fluid-structure interaction. For each of these two actions, numerical validations are presented and the analytical results are compared to finite-element solutions. [less ▲]

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See detailReview of existing solutions and presentation of a simplified method for the crashworthiness of lock gates
Buldgen, Loïc ULg; Ehlers, Sören; Le Sourne, Hervé et al

in Proceedings of the Smart Rivers 2015 Conference (2015, September)

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See detailA simplified analytical method to evaluate the seismic pressure on plane lock gates
Buldgen, Loïc ULg; Rigo, Philippe ULg; Le Sourne, Hervé

in Engineering Structures (2015), 100

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See detailA simplified analytical method to estimate the resistance of plane lock gates impacted by river barges
Buldgen, Loïc ULg; Le Sourne, Hervé; Rigo, Philippe ULg

in Marine Structures (2015), 43

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See detailULTIMATE STRENGTH - Discussion on Committee III.1- ISSC 2012's report
Rigo, Philippe ULg

in Fricke, Wolfgang; Bronsart, Robert (Eds.) PROCEEDINGS OF THE 18TH INTERNATIONAL SHIP AND OFFSHORE STRUCTURES CONGRESS - VOLUME 3 (2015)

Concern for the ductile behavior of ships and o shore structures and their structural components under ultimate conditions. Attention shall be given to the influence of fabrication imperfections and in ... [more ▼]

Concern for the ductile behavior of ships and o shore structures and their structural components under ultimate conditions. Attention shall be given to the influence of fabrication imperfections and in-service damage and degradation on reserve strength. Uncertainties in strength models for design shall be highlighted. [less ▲]

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See detailNumerical crashworthiness analysis of an offshore wind turbine monopile impacted by a ship
Bela, Andreea ULg; Le Sourne, Hervé; Buldgen, Loïc ULg et al

in Shenoi, R Ajit; Soares, Carlos Guedes (Eds.) Analysis and Design of Marine Structures (2015, March)

The consequences of collision events can range from minor structural damages of the supporting structure to complete collapse of the wind turbine, which may lead to disruptions of the electricity ... [more ▼]

The consequences of collision events can range from minor structural damages of the supporting structure to complete collapse of the wind turbine, which may lead to disruptions of the electricity production and, at worst, to sinking of the striking ship with probability of loss of human lives or/and pollution. For all these reasons, a collision risk analysis becomes mandatory at the pre-design stage in order to identify the collision scenarios having the greatest probabilities of occurrence, to estimate the consequences of collision events and to ensure safe operations through the wind farm service life. The goal of this paper is to outline the behavior of the monopile foundations during ship collision by performing non-linear finite element simulations. Many collision scenarios are analyzed in order to study the sensitivity of the monopile to various parameters like impact striking ship velocity, nacelle mass, wind direction, soil stiffness, vertical location of the impact point, wind orientation … The internal energy dissipated by deformation of the monopile, the crushing force and the indentation of the crushed area are compared for different situations, as well as the overall displacements of the supporting structure. [less ▲]

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See detailShip collision on monopile offshore wind turbines
Bela, Andreea ULg; Le Sourne, Hervé; Buldgen, Loïc ULg et al

Poster (2015)

Every year, the offshore wind industry is expanding and the location of the future wind farms tends to move to deeper waters and closer to the traffic lanes. The consequence of this growth is that the ... [more ▼]

Every year, the offshore wind industry is expanding and the location of the future wind farms tends to move to deeper waters and closer to the traffic lanes. The consequence of this growth is that the probability of ship collisions will increase. For any new offshore wind farm projects, a collision risk analysis must be performed in order to identify the collision scenarios having the greatest probabilities of occurrence and to evaluate the consequences on the supporting structure and also on the mechanical parts of the wind turbines. The goal of this paper is to outline the behaviour of the monopile foundations during ship collision by performing non-linear finite elements simulations. Many collision scenarios are analysed in order to study the sensitivity of the monopile to a series of parameters like impact velocity of the striking ship, wind loads and soil stiffness. [less ▲]

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See detailPIANC Report 140 - Semi-probabilistic design concept for inland hydraulic structures
PIANC WG 140; Rigo, Philippe ULg; Buldgen, Loïc ULg

Book published by PIANC (2015)

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See detailA review of technical solutions and simulations approaches for ship collisions with lock gates
Ehlers, S; Le Sourne, H; Buldgen, Loïc ULg et al

in Ship Technology Research = Schiffstechnik (2015), 62

Development of Analytical method sto assess the ship impact on lock gates

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See detailResidual Ultimate Strength of Cracked Steel Unstiffened and Stiffened Plates under Longitudinal Compression
Bayatfar, Abbas ULg; Rigo, Philippe ULg

in Thin-Walled Structures (2014), 84

This paper numerically deals with the influence of cracks (in terms of length and location) on the ultimate compressive strength characteristics of unstiffened and stiffened plate elements used in thin ... [more ▼]

This paper numerically deals with the influence of cracks (in terms of length and location) on the ultimate compressive strength characteristics of unstiffened and stiffened plate elements used in thin-walled structures. The cracks were presumed to be through-thickness, having no contact between their faces and no propagation was allowed. A series of nonlinear finite element analyses was conducted using ANSYS commercial finite element code in which the Newton-Raphson method has been employed to solve the nonlinear governing equations. This study indicates that the length of cracks and especially its location can significantly affect the ultimate strength characteristics of unstiffened and stiffened plate elements subjected to axial compressive action. [less ▲]

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