Institutt for marin teknikk
Recent Submissions
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Design Optimization of Spar Floating Wind Turbines Considering Different Control Strategies
(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 ... -
Transient Performance in Dynamic Positioning of Ships: Investigation of Residual Load Models and Control Methods for Effective Compensation
(Doctoral theses at NTNU;2020:355, Doctoral thesis, 2020)This thesis concerns how the dynamic positioning (DP) control system can better handle transient events, where the loads experienced by the vessel change significantly over a short time frame. The material is intended for ... -
Observations from hydrodynamic testing of a flexible, large-diameter monopile in irregular waves
(Peer reviewed; Journal article, 2020)As the offshore wind industry moves toward larger wind turbines and deeper water, wave-induced loads on large-diameter monopiles are of increasing importance for ultimate limit state design checks. The combination of a ... -
Consequences of load mitigation control strategies for a floating wind turbine
(Peer reviewed; Journal article, 2020)Several approaches to avoid control-induced resonances of floating wind turbines have been proposed. The main focus has been on reductions in global motions and loads in the tower base. In the present work, we examine the ... -
Non-linear hydroelastic response of a monopile foundation in regular waves
(Peer reviewed; Journal article, 2020)This paper presents an original contribution to the coupled hydroelastic simulation of offshore wind turbines foundations. A non-linear coupled simulation tool has been developed to calculate the response of these systems. ... -
Modular Conceptual Synthesis of Low-Emission Ships
(Chapter, 2020)With the ambition of lowering emission from shipping, today’s ship designers face both the freedom and challenge to select from a large set of different ship system concepts during the conceptual design stage. In order to ... -
Effects of Wind-Wave Misalignment on a Wind Turbine Blade Mating Process: Impact Velocities, Blade Root Damages and Structural Safety Assessment
(Peer reviewed; Journal article, 2020)Most wind turbine blades are assembled piece-by-piece onto the hub of a monopile-type offshore wind turbine using jack-up crane vessels. Despite the stable foundation of the lifting cranes, the mating process exhibits ... -
Arctic Vision: Using Neural Networks for Ice Object Classification, and Controlling How They Fail
(Peer reviewed; Journal article, 2020)Convolutional neural networks (CNNs) have been shown to be excellent at performing image analysis tasks in recent years. Even so, ice object classification using close-range optical images is an area where their use has ... -
On Down-Scaled Modelling of Wind Turbine Drivetrains
(Peer reviewed; Journal article, 2020)Gearbox testing is an important and complex task that will become even more challenging as the wind industry moves towards ever-growing turbines. The burden of this task can be decreased by using reduced-scale models with ... -
A systems-theoretic approach to hazard identification of marine systems with dynamic autonomy
(Peer reviewed; Journal article, 2020)Autonomous marine systems may switch between various operational modes with different levels of autonomy (LoA), due to a rapidly changing environment and the complex nature of tasks. The dynamic autonomy brings an additional ... -
Natural frequency estimation by using torsional response, and applications for wind turbine drivetrain fault diagnosis
(Journal article; Peer reviewed, 2020)A method based on torsional vibration measurements for a system-level condition monitoring of the drivetrain system is developed in this paper. The latter is tested by using a 10MW wind turbine drivetrain simulation model, ... -
Operational limits for aquaculture operations from a risk and safety perspective
(Peer reviewed; Journal article, 2020)Current decision making regarding whether to abort a high-risk aquaculture operation in a Norwegian fish farm is mainly experience-driven. The on-site personnel decides whether to start/delay/abort operations primarily ... -
Design and Analysis of Mooring System for Semi-submersible Floating Wind Turbine in Shallow Water
(Doctoral thesis, 2020)Floating wind turbines are necessary to produce power from wind in deeper water where bottom-fixed wind turbines are not economically competitive. However, it is still not clear to which water depth a floating wind turbine ... -
Numerical study on the heading misalignment and current velocity reduction of a vessel-shaped offshore fish farm
(Peer reviewed; Journal article, 2019)Recently, the concept of a vessel-shaped fish farm was proposed for open sea applications. The fish farm comprises a vessel-shaped floater, five fish cages, and a single-point mooring system. Such a system weathervanes, ... -
A Three-Dimensional Model for Strength Assessment of Type-C Independent Cargo Tank Structures
(Peer reviewed; Journal article, 2020)For the analysis of the arrangement and strength of Type-C independent cargo tank structures, the linear spring or rod elements are usually used to model supporting woods, in which one-dimensional and linear contact behaviors ... -
Active Single-Blade Installation Using Tugger Line Tension Control and Optimal Control Allocation
(Peer reviewed; Journal article, 2020)The single-blade installation is a common method for the installation of wind turbine blades. In an offshore installation, a jackup vessel is often involved, and a crane is used to lift, move, and bolt each blade onto the ... -
Observations of Turbulence at a Near-Surface Temperature Front in the Arctic Ocean
(Peer reviewed; Journal article, 2020)High‐resolution ocean temperature, salinity, current, and turbulence data were collected at an Arctic thermohaline front in the Nansen Basin. The front was close to the sea ice edge and separated the cold and fresh surface ... -
Operability robustness index as seakeeping performance criterion for offshore vessels
(Peer reviewed; Journal article, 2020)The offshore industry operates increasingly large installations in exposed areas requiring high reliability and availability. Downtime of complex offshore systems leads to significant financial losses. Towards year-round ... -
Fluid flow in steady and oscillatory lid-driven square cavities
(Peer reviewed; Journal article, 2017)This paper presents numerical simulations of steady and oscillatory lid-driven cavity flow at different Reynolds numbers with a fixed aspect ratio of 1:1. A projection method (P2 pressure correction method) is applied to ... -
Incorporating software failure in risk analysis – Part 1: Software functional failure mode classification
(Peer reviewed; Journal article, 2020)Advanced technological systems consist of a combination of hardware and software, and they are often operated or supervised by a human operator. Failures in software-intensive systems may be difficult to identify, analyze, ...
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