The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Guedes C Soares - One of the best experts on this subject based on the ideXlab platform.
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evaluation of Fatigue Damage model predictions for fixed offshore wind turbine support structures
International Journal of Fatigue, 2016Co-Authors: B Yeter, Yordan Garbatov, Guedes C SoaresAbstract:Abstract This work deals with the evaluation of the spectral Fatigue Damage prediction of a tripod offshore wind turbine support structure subjected to combined stochastic wave and wind – induced loads. The stochastic loadings are defined using the sea states based on a scatter diagram related to the North Atlantic. Further, the power spectral density of the hot spot stress is estimated accordingly. The prediction of Fatigue Damage is evaluated in several spectral Fatigue Damage models including the Rayleigh, Wirsching–Light, Tunna, α 0.75, Tovo and Benasciutti, Zhao–Baker, Rice and Dirlik models. Critical hot spot locations, which experience the most Fatigue Damage, are analysed based on the finite element method and the S – N Fatigue Damage approach. The time-domain solution based on the rainflow cycle counting method is assumed to be the “real” data and the model that best fits the Fatigue Damage of the wind turbine support structure is identified with the Akaike’s Information Criterion.
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spectral Fatigue Damage assessment of tanker deck structural detail subjected to time dependent corrosion
International Journal of Fatigue, 2013Co-Authors: Tran K Nguyen, Yordan Garbatov, Guedes C SoaresAbstract:Abstract The paper presents a spectral Fatigue Damage analysis of a double hull tanker structural detail accounting for corrosion wastage over time. The cyclic load of the wave-induced vertical bending moment, analysis using a strip theory on the frequency domain, is considered for two loading conditions. The influence of sea environment parameters and operational profiles including the use of different scatter diagrams, and wave variance spectra have been analyzed. The effect on the time-dependent cumulative Fatigue Damage as a function of corrosion deterioration is calculated.
Yan Gao - One of the best experts on this subject based on the ideXlab platform.
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short term extreme response and Fatigue Damage of an integrated offshore renewable energy system
Renewable Energy, 2018Co-Authors: Zhengshun Cheng, Zhiming Yuan, Yan GaoAbstract:Abstract This study addresses short-term extreme response and Fatigue Damage of an integrated wind, wave and tidal energy system. The integrated concept is based on the combination of a spar type floating wind turbine, a wave energy converter and two tidal turbines. Aero-hydro-mooring coupled analysis is performed in time-domain to capture the dynamic response of the combined concept in a set of environmental conditions. The mean up-crossing rate method is used to evaluate the extreme response, which takes advantage of an extrapolation method to reduce the simulation sample size. The cumulative Fatigue Damage is computed based on the S-N method. Simulation results show that the tower base fore-aft bending moment is improved, in terms of extreme value and Fatigue Damage. Nevertheless, the tension force of a mooring line is worsened. The mooring line bears increased maximum tension due to the tidal turbine thrust force and it is subjected to higher Fatigue Damage load as well.
Zhengshun Cheng - One of the best experts on this subject based on the ideXlab platform.
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short term extreme response and Fatigue Damage of an integrated offshore renewable energy system
Renewable Energy, 2018Co-Authors: Zhengshun Cheng, Zhiming Yuan, Yan GaoAbstract:Abstract This study addresses short-term extreme response and Fatigue Damage of an integrated wind, wave and tidal energy system. The integrated concept is based on the combination of a spar type floating wind turbine, a wave energy converter and two tidal turbines. Aero-hydro-mooring coupled analysis is performed in time-domain to capture the dynamic response of the combined concept in a set of environmental conditions. The mean up-crossing rate method is used to evaluate the extreme response, which takes advantage of an extrapolation method to reduce the simulation sample size. The cumulative Fatigue Damage is computed based on the S-N method. Simulation results show that the tower base fore-aft bending moment is improved, in terms of extreme value and Fatigue Damage. Nevertheless, the tension force of a mooring line is worsened. The mooring line bears increased maximum tension due to the tidal turbine thrust force and it is subjected to higher Fatigue Damage load as well.
Yordan Garbatov - One of the best experts on this subject based on the ideXlab platform.
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evaluation of Fatigue Damage model predictions for fixed offshore wind turbine support structures
International Journal of Fatigue, 2016Co-Authors: B Yeter, Yordan Garbatov, Guedes C SoaresAbstract:Abstract This work deals with the evaluation of the spectral Fatigue Damage prediction of a tripod offshore wind turbine support structure subjected to combined stochastic wave and wind – induced loads. The stochastic loadings are defined using the sea states based on a scatter diagram related to the North Atlantic. Further, the power spectral density of the hot spot stress is estimated accordingly. The prediction of Fatigue Damage is evaluated in several spectral Fatigue Damage models including the Rayleigh, Wirsching–Light, Tunna, α 0.75, Tovo and Benasciutti, Zhao–Baker, Rice and Dirlik models. Critical hot spot locations, which experience the most Fatigue Damage, are analysed based on the finite element method and the S – N Fatigue Damage approach. The time-domain solution based on the rainflow cycle counting method is assumed to be the “real” data and the model that best fits the Fatigue Damage of the wind turbine support structure is identified with the Akaike’s Information Criterion.
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spectral Fatigue Damage assessment of tanker deck structural detail subjected to time dependent corrosion
International Journal of Fatigue, 2013Co-Authors: Tran K Nguyen, Yordan Garbatov, Guedes C SoaresAbstract:Abstract The paper presents a spectral Fatigue Damage analysis of a double hull tanker structural detail accounting for corrosion wastage over time. The cyclic load of the wave-induced vertical bending moment, analysis using a strip theory on the frequency domain, is considered for two loading conditions. The influence of sea environment parameters and operational profiles including the use of different scatter diagrams, and wave variance spectra have been analyzed. The effect on the time-dependent cumulative Fatigue Damage as a function of corrosion deterioration is calculated.
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Fatigue Damage assessment of corroded oil tanker details based on global and local stress approaches
International Journal of Fatigue, 2012Co-Authors: K. Tran Nguyen, Yordan Garbatov, C. Guedes SoaresAbstract:Abstract Fatigue Damage assessment of double hull oil tanker structural details is performed, based on global and local structural finite element models. The wave-induced vertical and horizontal bending moments, as well as local pressure loads are accounted for in the Fatigue Damage calculations. Local stress analyses are considered based on the notch stress approach. Time-dependent stresses as a function of corrosion deterioration are analyzed based on nonlinear corrosion wastage during the design life of ship. The effective notch stress approach is applied for analyzing the stress distributions and the Fatigue Damage of the welded joint at two hotspots. The hotspots are located between the flat bar stiffener of a transverse web frame and the flange of a longitudinal stiffener at the side shell of a tanker ship hull. The details under consideration are modeled separately in a fine mesh employing the sub model techniques. Finally the Fatigue Damage assessment accounting for corrosion deterioration of the considered hotspots is analyzed.
Michael S. Triantafyllou - One of the best experts on this subject based on the ideXlab platform.
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monitoring viv Fatigue Damage on marine risers
Journal of Fluids and Structures, 2009Co-Authors: Harish Mukundan, Yahya Modarressadeghi, Jason Dahl, Franz S. Hover, Michael S. TriantafyllouAbstract:Long flexible cylinders (e.g., risers, tendons and mooring lines) exposed to the marine environment encounter ocean currents leading to vortex-induced vibration (VIV). These oscillations, often driven at high frequencies over extended periods of time, may result in structural failure of the member due to Fatigue Damage accumulation. Recent developments in instrumentation and installation of data acquisition systems on board marine risers have made accurate measurement of riser responses possible. This paper aims at using the data from these data acquisition devices (typically strain gages and accelerometers) in order to understand the evolution of the riser VIV, with the final aim of estimating the Fatigue Damage. For this purpose we employ systematic techniques to reconstruct riser VIV response using the data from the available sensors. The reconstructed riser response allows estimation of the dynamic axial stresses due to bending and consequently the estimates of the Fatigue Damage along the entire riser. The above methods can take into account the Fatigue Damage arising from complicated riser motions involving the presence of traveling waves even with the use of very few sensors. An alternate approach using a Van der Pol wake oscillator model is also explored to obtain Fatigue life estimates caused by riser VIV.
