Multibody Dynamic Analysis of the Lift Off Operation: A Time Domain Approach

In the coming decades, the offshore decommissioning industry is becoming a quickly growing market, especially at the North Sea, where most offshore platforms have operated for more than twenty years. There is little room for the mistake in the offshore decommissioning operation, therefore the motion response analysis is essential to avoid the...

Improving the Stewart Platform Design of the Ampelmann System for Asymmetric Load Cases

The Ampelmann system consists of a motion compensating Stewart platform and a telescoping connection bridge, a gangway. The gangway creates a large asymmetric load case on top of the Stewart platform. The purpose of this study is to make the A-type operable for larger gangways by investigating the possibilities to reduce the cylinder forces by...

Probabilistic estimation of fatigue loads on monopile-based offshore wind turbines

Offshore wind energy faces three important trends: (1) wind farms grow in size, (2) monopiles are installed in deeper water, and (3) cost reduction remains the most important challenge. With wind farm size, the importance of variations in environmental site conditions across the wind farm increases. These site variations, e.g. water depth and...

Design of a probabilistic decision support tool for the cable installation of an offshore wind farm

During the past years a lot of attention has been drawn towards the development of renewables, due to the expected depletion of fossil fuels and political decisions. Offshore wind energy is considered as one of the most promising renewable energy sources, however the cost of offshore wind farms have not yet reached competitive levels. Hence...

Dynamics of Flexible Risers for Deep Sea Mining Applications

The objective of this thesis is to develop a numerical model, which could be used to predict the deflections and stresses in the flexible risers during one operation cycle. The numerical model of the flexible risers is mainly developed based on Timoshenko Beam Theory and Discrete Element Method. The internal slurry flow is simulated as plug flow...

Dynamic behaviour of floating wind turbines - A comparison of open water and level ice conditions

In the past couple of decades, the offshore wind industry has developed from applications in shallow water to ever deeper, more remote locations with harsher environments. In these progressively larger water depths, bottom founded support structures become no longer applicable and floating support structures could provide a viable alternative....

The Modelling of Suction Caisson Foundations for Multi-Footed Structures

Suction caissons are a type of offshore foundation that allow for fast and noise-free installation and decommissioning of offshore structures. They have been used for 30 years in the oil and gas industry and are also becoming more common in the offshore wind sector as a promising way to cost reduction, both for foundations of single turbines and...

Nonlinear Wave Loads on Offshore Wind Support Structure

Though booming, offshore wind development is constrained by its high cost. One potential way to meet this challenge is to reduce the uncertainty in wave modeling and hydrodynamic loads calculation model for offshore wind support structure design. The thesis covers two aspects for calculating loads acting on a offshore wind support structure: an...

Modelling and Steering of Tuggerwinches

This report described the study of the Tuggerwinch system used by Heerema Marine Contractors SE.

Validity of Identified Modal Parameters based on Rotor-Stop Tests of Offshore Wind Turbines

The increasing energy prices together with the uncertainty about long term sufficiency of fossil fuel resources, confirm the increasing need for reliable alternatives based on renewable energy. Offshore wind power, particularly, has a great potential in providing a large share of the energy demand. The sustainable character of this energy...

Numerical modeling of dam-reservoir interaction seismic response using the Hybrid Frequency–Time Domain (HFTD) method

The research work studies the fundamentals of the Hybrid Frequency-Time Domain (HFTD) method for dynamic analysis of structures, applied to the seismic analysis of dam-reservoir interaction systems. The theoretical consistency and accuracy of the HFTD method, based on the frequency domain Fourier analysis, is demonstrated through all the parts...

Local buckling collapse of marine pipelines

To keep up with the growing demand for oil and gas, the oil and gas industry ventures into deeper waters. For a deep water pipeline project, South Stream, a pipeline test program is developed. Part of this program is the investigation of the resistance of an externally pressurised pipeline against local buckling collapse. This is a decisive...

Investigation of damping in high-rise buildings: Identification and prediction of damping in the serviceability limit state for wind-induced vibrations

Buildings must be designed to meet horizontal deformation and vibration requirements when loaded by a wind force. These requirements can be governing in the design of the load bearing structure of a high-rise building. The structure can be optimized by describing and analyzing its dynamic behaviour. Information on damping is required to...

Estimation of the Vibration Decrement of an Offshore Wind Turbine Support Structure Caused by its Interaction with Soil

In today’s cutting costs environment in the offshore wind industry, significant achievements can be made with a better assessment of dynamic soil-pile interaction. More knowledge regarding the contribution of the dynamic soil-pile interaction to damping of an offshore wind turbine structure (OWT) could perceptibly reduce the fabrication costs of...

Dynamic behaviour of tunnel elements during the immersion process: A study to the influence of swell waves and wind waves on the immersion system

Immersion of tunnels is an often used technique in rivers and canals. The transport of tunnel elements can be done under offshore conditions, but immersing the elements under these conditions is not common practise. The tunnel elements of the Busan-Geoje Fixed Link in South Korea were immersed in such a situation. During this process, several...

Traffic induced vibrations in floating thoroughfares

Feasibility study on a floating thoroughfare that is submitted to the dynamic loading of vehicles

Hydrodynamic pressures on large lock structures

When a navigation lock, dam, or any other structure with water is subjected to an earthquake, one of the dynamic loads will be hydrodynamic pressure. This is the pressure exerted by the fluid on the structure as a result of the different behavior in motion of solid and fluid. To determine this pressure there are several available methods which...

Parametric Instability of Deep-Water Risers

During the last decade, some major changes took place in the offshore industry. These changes were associated with new oil and gas fields which were discovered in severe environments, at depths of 1500 meter and more. Nowadays, offshore companies face challenges in the design of risers which could reliably facilitate such deep-water exploration....