Browsing NTNU Open by Author "Hegseth, John Marius"
Now showing items 1-10 of 10
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A semi-analytical frequency domain model for efficient design evaluation of spar floating wind turbines
Hegseth, John Marius; Bachynski, Erin Elizabeth (Journal article; Peer reviewed, 2019)A linear model for efficient design evaluation of spar floating wind turbines is presented, and verified against a nonlinear time domain model with regards to long-term fatigue and short-term extreme response for two ... -
Application of a lumping method for fatigue design of monopile-based wind turbines using fully coupled and simplified models
Katsikogiannis, George; Hegseth, John Marius; Bachynski-Polic, Erin Elizabeth (Peer reviewed; Journal article, 2022)The study presents different methods for fatigue assessment of monopile-based offshore wind turbines. Their accuracy and computational time is compared to full long-term time domain results. The damage-equivalent lumping ... -
Assessment of Uncertainties in Estimated Wellhead Fatigue
Hegseth, John Marius (Master thesis, 2014)During subsea drilling, the motions of the Mobile Offshore Drilling Unit (MODU) and riser cause cyclic bending moments on the wellhead. This may lead to fatigue failure of the component, which can have severe consequences, ... -
Comparison and Validation of Hydrodynamic Load Models for a Semisubmersible Floating Wind Turbine
Hegseth, John Marius; Bachynski, Erin Elizabeth; Karimirad, Madjid (Chapter, 2018)In global aero-hydro-servo-elastic analyses of floating wind turbines (FWTs), the hydrodynamic loads are usually found from potential flow theory and applied in a single point of a rigid hull. When the hull is relatively ... -
Design Optimization of Spar Floating Wind Turbines Considering Different Control Strategies
Hegseth, John Marius; Bachynski, Erin Elizabeth; Martins, Joaquim R. R. A. (Peer reviewed; Journal article, 2020)One of the challenges related to the design of floating wind turbines (FWTs) is the strong interactions between the controller and the support structure, which may result in an unstable system. Several control strategies ... -
Effect of environmental modelling and inspection strategy on the optimal design of floating wind turbines
Hegseth, John Marius; Bachynski, Erin Elizabeth; Leira, Bernt Johan (Peer reviewed; Journal article, 2021)In order to reduce design conservatism and consequently the cost of energy, appropriate and cost-optimal safety factors should be derived, in light of environmental load uncertainties and lifetime costs. In the present ... -
Efficient Modelling and Design Optimization of Large Floating Wind Turbines
Hegseth, John Marius (Doctoral theses at NTNU;2020:356, Doctoral thesis, 2020)Floating wind turbines (FWTs) are considered a promising solution for wind energy harvesting in deep water, but are currently too expensive to compete with other energy sources. Being a relatively new and immature technology ... -
Frequency-Dependent Aerodynamic Damping and Inertia in Linearized Dynamic Analysis of Floating Wind Turbines
Silva de Souza, Carlos Eduardo; Hegseth, John Marius; Bachynski, Erin Elizabeth (Journal article; Peer reviewed, 2020)In frequency-domain (FD) models of floating wind turbines (FWT), it is common to regard the interaction between nacelle motions and thrust by means of a constant aerodynamic damping coefficient. This approach is effective ... -
Gradient-Based Design Optimization of Fully-Flexible Floating Wind Turbines Using Modal Analysis
Rohrer, Peter Joshua; Bachynski-Polic, Erin Elizabeth; Hegseth, John Marius (Chapter, 2023)A variety of substructure concepts for floating offshore wind have been developed. Design optimization can be used to efficiently explore this design space and guide further work. Previous design optimization studies have ... -
Integrated design optimization of spar floating wind turbines
Hegseth, John Marius; Bachynski, Erin Elizabeth; Martins, Joaquim R. R. A. (Peer reviewed; Journal article, 2020)A linearized aero-hydro-servo-elastic floating wind turbine model is presented and used to perform integrated design optimization of the platform, tower, mooring system, and blade-pitch controller for a 10 MW spar floating ...