The dynamic response of a wind turbine blade to downwind tower shadow

The quest for affordable renewable energy causes the need for bigger and more efficient wind turbines. To counter the problem of possible collisions between the growing turbine blades and the tower support structure, downwind turbines might be a solution. For this configuration, blade flexibility no longer forms a problem and besides that...

Study of nonlinear dynamic soil response to harmonic excitation using semi-analytical and numerical methods

The strive for cleaner energy sources is one of the most demanding problems the world faces today. The role of offshore wind in the energy transition is becoming increasingly relevant. One of the areas where the industry expects to reduce conservatism and uncertainty in design is the interaction of the foundations of offshore wind turbines with...

Global Dynamic Fluid-Structure-Interaction Analysis for a Submerged Floating Tunnel

This thesis aims to gain insight into the global dynamic fluid-structure interaction response of a submerged floating tunnel (SFT) under the wave and current loading to enhance the design. To this end, the tunnel tube is modelled as a Euler-Bernoulli beam deformed in three directions (horizontal displacement, vertical displacement, rotational...

Non-linear dynamic response of a beam using an impulse response method based on linear complex modes

The purpose of this thesis is to formulate and test a computational method, based on linear complex modes, to calculate the dynamic response of a beam with a boundary dashpot excited by a non-linear response-dependent dissipative force. This impulse response method is a time-stepping method which iteratively approximates the non-linear force by...

Capturing 3D Continuum Effects in a 1D Soil-Structure Interaction Model for Seismic Analysis of Offshore Wind Turbines

Offshore wind energy is considered a necessary energy resource, that may stimulate the transition from fossil fuels. Following the successful development in Western Europe, offshore wind is quickly gaining momentum in the Asia-Pacific region. At variance with North-Sea based offshore wind turbines (OWTs), structures installed in the Asia-Pacific...

Dynamic Fluid-Structure-Vehicle-Interaction Analysis for Submerged Floating Tunnels: A Comfort Assessment

Crossing waterways is crucial to improve transport connections.<br/>In particular, new crossing methods are needed when the distance to be covered increases. Submerged Floating Tunnels (SFT) have been recently emerging as a cost-effective feasible crossing technique to connect fjords in Norway. However, only very little research has addressed...

The interaction of a submerged floating tunnel with a moving vehicle

Due to the high cost of long spanned bridges or deep tunnels, the interest into a submerged floating tunnel (SFT) has reemerged. In the last twenty years many studies on the SFT have been performed. This report investigates the interaction between a single vehicle, moving at constant velocity, and the SFT. The research is limited to the dynamic...

Dynamic interaction between a moving vehicle and a bridge: Theoretical model and application of a complex mass-spring system, moving across a simply supported bridge

When a vehicle moves across a bridge, there is always an interaction between the vehicle and the bridge and within the vehicle itself. It is important to predetermine the vibrations in the bridge and vehicle. This way, the Ultimate Limit State (ULS) and Serviceability Limit State (SLS) can be more accurately determined, compared to a static...

Instability of a high-speed vehicle moving through a tunnel embedded in a visco-elastic half-plane: The Hyperloop case

Hyperloop is a high-speed transportation mode which operates by sending magnetically levitated capsule-like vehicles through a near vacuum tunnel. Due to the reduced air resistance and friction, speeds exceeding those of modern aircraft should become possible. When the system is moved underground,<br/>the stability of vehicle vibrations may...

Topology Optimization of Wave Barriers: Development of a tool for use in engineering practice

Wave barriers are a common mitigation measure when dealing with environmentally induced vibrations. These wave barriers generally consist of stiff vertical walls buried in the soil to impede waves on their path from the source to the receiver. The geometries of the wave barriers that are used in practice are very simple. More complex geometries...

Theoretical model and application of a damped two degree of freedom spring-mass system moving across a simply supported beam

In this bachelor thesis a theoretical model is developed for the dynamic loading of a simply supported beam.

Enhanced Bounding Surface Modeling of Sand Behaviour under Multiple Loading Cycles

Cyclic behaviour of soil has stimulated researchers for several decades to develop constitutive models that will be able make accurate predictions of soil behaviour and at the same time they will be simple to use. Constitutive models are considered to be more valid compared to empirical models, because they comprise by equations that have actual...

The dynamic response of an embedded cavity in a half-space subjected to SH waves using the Boundary Element Method

A reciprocity-based direct boundary integral method and indirect boundary integral method have been introduced and used to obtain the two-dimensional response of a cylindrical cavity embedded in a uniform elastic half space subjected to SH wave. By introducing free wave field and the actual field with a cavity, the key point to solve for...

Structure-soil interaction for horizontally polarised shear waves: Formulating SH-waves in a homogeneous elastic continuum with generalised boundary conditions

When modelling a structure-soil system, interaction stresses at the interface of the structure and the surface of soil layer influence the dynamic behaviour of the system. These interaction stresses are not accounted for in many simplified models that evaluate the behaviour of the soil layer and the structure separately. Modelling a fully...

Definition and Response Validation of a Simplified Aero-Servo-Elastic Wind Turbine Model

Currently, the foundation design of offshore wind turbines is based on a simple cantilever beam model with a mass representing the rotor and nacelle, or by making use of wind turbine simulation software such as Bladed, which are built for rotor design. The simple models are unrealistic since the dynamic interaction between the aerodynamic loads,...

Structural integrity assessment of self-elevating units with fatigue and corrosion damage based on actual load history

Seafox owns and operates a fleet of 12 Jack-ups. The design life of these Jack-ups is typically around 30 years. However, some have remained operational after exceeding their design life. It is therefore critical to gain an understanding how long and under what conditions these jacks-ups are still able to operate safely. There are two main...