Blar i Institutt for marin teknikk på emneord "VDP::Technology: 500::Marine technology: 580"
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Digital Twins for Fault Prognosis in Offshore Wind Turbine Drivetrains
(Doctoral theses at NTNU;2024:178, Doctoral thesis, 2024)This thesis investigates the relatively novel concept of Digital Twin (DT) in the context of offshore wind turbine drivetrains. DT can be described as a virtual representation of a system or asset that calculates system ... -
Ducted Propellers: Behaviour in Waves and Scale Effects
(Doctoral thesis at NTNU;2015:299, Doctoral thesis, 2015)Ducted propellers find their application in a wide range of marine vessels, such as cargo ships, tugboats, submarines, trawlers etc. Preference over the open propeller depends on a variety of factors, the most common ... -
Dynamic Analysis and Design of Gearboxes in Offshore Wind Turbines in a Structural Reliability Perspective
(Doctoral thesis at NTNU;2015:191, Doctoral thesis, 2015)The drivetrain is the heart of the wind turbine. In wind turbines, the wind's kinetic energy is converted to electrical power through the drivetrain which often consists of a gearbox and a generator. The drivetrain is ... -
Dynamic Analysis in Design and Operation of Large Floating Offshore Wind Turbine Drivetrains
(Doctoral theses at NTNU;2020:403, Doctoral thesis, 2020)This thesis presents a versatile rotor-bearing simulation model, including elements required to model rolling-element bearings as main bearings in large floating offshore wind turbines. Furthermore, the thesis presents new ... -
Dynamic Analysis of the Installation of Monopiles for Offshore Wind Turbines
(Doctoral thesis at NTNU;2016:139, Doctoral thesis, 2016)The installation of offshore wind farms presents great challenges as the industry move farther offshore and into deeper waters, and the turbines and foundations are getting larger and heavier. Current installation methods ... -
Dynamic Positioning of Marine Vessels in Ice
(Doctoral thesis at NTNU;2016:168, Doctoral thesis, 2016)This thesis is a collection of papers focusing on various aspects of dynamic positioning of marine vessels in ice. Most emphasis is put on the dynamic broken, or managed, sea-ice environment where pioneering operations ... -
Dynamic Response of Flexible Risers due to Unsteady Slug Flow
(Doctoral thesis at NTNU;2015:182, Doctoral thesis, 2015)In this work the influence of unsteady slug flow on the dynamic response of flexible risers is analysed using a computational tool consisting of one program for prediction of slug flow development, and another program ... -
Dynamic Simulation of a Hydraulic Cylinder for Heave Compensation of Deepwater Drilling Risers
(Doctoral thesis at NTNU;2014:320, Doctoral thesis, 2014)This thesis presents global finite element simulations of a hydro-pneumatic riser tension cylinder used for tensioning and heave compensating of marine drilling risers. The global finite element models are made for use ... -
Effectiveness in Decision-Making in Ship Design under Uncertainty
(Doctoral theses at NTNU;2020:53, Doctoral thesis, 2020)The objective of this thesis is to develop a better understanding of how to carry out more effective conceptual ship design processes. Under the premise that uncertainty influences the effectiveness of the decision-making ... -
Energy efficiency and emission abatement in the fishing fleet
(Doctoral theses at NTNU;2016:332, Doctoral thesis, 2016)Operation of fishing vessels is energy demanding. On one hand, fuel costs and preference of customers for buying “green” seafood products challenge economic feasibility of fisheries. On the other hand, environmental concerns ... -
Experimental and Numerical Hydrodynamic Analysis of a Damaged Ship Section In Waves
(Doctoral theses at NTNU;2020:361, Doctoral thesis, 2020)In the past few decades, ships have become larger, efficient, durable but the danger of accidental events like grounding, collision etc. continues to be a major issue in ship operations. Following a damage event, a ship ... -
Experimental and Numerical Study of a Combined Offshore Wind and Wave Energy Converter Concept
(Doctoral thesis at NTNU;2016:205, Doctoral thesis, 2016)Clean and renewable energy is increasingly emphasized with the growing public attention to the environmental pollution problem. Among renewable energy resources, both offshore wind and wave energy are resources with great ... -
Experimental and numerical study of hydrodynamic responses of a twin-tube submerged floating tunnel considering vortex-induced vibration
(Doctoral theses at NTNU;2020:392, Doctoral thesis, 2020)A pontoon-supported submerged floating tunnel (SFT) is a reasonable means crossing a fjord with large depth and width. A relevant design of such a tunnel consists of two identical tubes in a tandem configuration and suspended ... -
Experimental and Theoretical Investigations on the Ship Resistance in Level Ice
(Doctoral theses at NTNU;2019:198, Doctoral thesis, 2019)The growing interest in Arctic transportation and field logistics leads to an increasing demand for ships with good ice breaking performance. The ice breaking performance of ships is usually defined by their ability to ... -
Experimental Investigation of Injection and Combustion Processes in Marine Gas Engines Using Constant Volume Rig
(Doctoral theses at NTNU;2019:96, Doctoral thesis, 2019)In circumstances of the strong demand for a reduction of harmful emissions from ships, one of the main pathways of the development of marine power plants is improvement of the existing and development of new gas engine ... -
Fatigue assessment of welded joints taking into account effects of residual stress
(Doctoral thesis at NTNU;2014:311, Doctoral thesis, 2014)The aim of the study is to contribute towards a better understanding of the effect of residual stress and shakedown on fatigue strength of welded joints. Residual stress may have a significant effect on the fatigue ... -
Fatigue Performance of Copper Power conductors
(Doctoral thesis at NTNU;2015:148, Doctoral thesis, 2015)The present work is concerned with the fatigue strength of copper power conductors applied in umbilicals and power cables. Two cross-sections of conductors were investigated, namely, 95 mm2 and 300 mm2. The work included ... -
Fault Diagnosis of Floating Wind Turbine Drivetrain- Methodologies and Applications
(Doctoral theses at NTNU;2018:286, Doctoral thesis, 2018)Increasing demand for renewable energy is driving innovation and attracting many research resources all over the world. Wind energy is one of the most promising sources of renewable energy. Wind turbine has been in use for ... -
Fidelity of Cyber-Physical Empirical Methods Application to the active truncation of slender marine structures
(Doctoral theses at NTNU;2018:405, Doctoral thesis, 2018)Cyber-physical empirical methods (CPEMs) are empirical methods in which a dynamical system under study is partitioned into physical and numerical substructures. While the numerical substructures are described by validated ... -
Formal approaches to design and verification of safe control systems for autonomous vessels
(Doctoral theses at NTNU;2023:70, Doctoral thesis, 2023)Maritime autonomy can positively impact society by cutting costs and emissions while enabling new solutions for transportation and mobility. Autonomous vessels must be capable of performing complex tasks under significant ...