Underwater detection has garnered increasing attention in recent years due to its broad and impactful applications in marine ecological research, underwater structural inspection, archaeological exploration, and deep-sea resource extraction. However, despite the proliferation of research in this domain, a comprehensive methodology that addresses both object identification and localization in underwater scenarios remains absent. Existing studies tend to treat these two tasks separately, often omitting the practical implementation details necessary for real-world deployment. This fragmented approach limits the effectiveness and adaptability of underwater detection systems, particularly in dynamic or unpredictable marine conditions.
To bridge this gap, this report presents a detailed exploration of a camera-based framework for simultaneous object identification and localization in underwater environments. The proposed system leverages a Region-based Convolutional Neural Network (RCNN) for object identification, offering a favorable trade-off between precision and computational efficiency. RCNN's architecture enables it to effectively handle the complex visual features typically present in underwater imagery. For the localization task, two complementary strategies are employed: the Metric3D depth estimation algorithm, which utilizes learned monocular cues to infer depth maps with high accuracy, and a geometry-based method rooted in camera imaging principles, which estimates object distance based on intrinsic and extrinsic camera parameters. The former localization method (Metric 3D) is more computationally expensive, but it provides more robust results and easier applications.
Experimental evaluations demonstrate that the proposed integrated approach achieves robust performance in various underwater conditions. The RCNN consistently delivers accurate object classifications, while the localization strategies offer flexibility and reliability depending on the computational and environmental constraints.
Overall, this research contributes a novel and practical solution for real-time underwater object detection by unifying identification and localization. The proposed system enables safer navigation, more precise manipulation, and greater situational awareness. By addressing the methodological gaps in existing literature and emphasizing real-world applicability, this work contributes to the research of intelligent underwater operation and automation.

The Nahuel Huapi National Park, in the Lake District of Northern Patagonia, Argentina, is well known for its tourism industry all year round. After COVID-19, the area saw a significant increase in the number of tourists traveling to the area. This means that the lake located in the heart of the district, Lago Nahuel Huapi, is being used more and more to explore the environmental richness of the area by boat. Now, the capacity of mooring spaces is no longer sufficient in the region, resulting in the construction of illegal private docks along the shore. To reduce this impact on the environment the authorities granted in 2024 a concession to develop one of the last not yet commercialized marina’s in the region: the marina in Bahía López.

This report provides a consult for the concessionaire of this development. The process begins with a research phase, consisting of an area study, and the mapping of environmental and hydrodynamic constraints. Subsequently, stakeholders are categorized, as the development of a marina in a national park entails complex regulations from multiple organizations. The outcomes of the research phase are translated into specific functional requirements for the marina. These functional requirements are the basis for the next phase, the design phase. This phase begins with the formulation of a design vision statement, formulating the project response to local conditions. Based on this, three different conceptual designs with various technical solutions are developed. Through a multi-criteria analysis, the concepts are tested on their robustness in order to chose a final concept. This concept is then elaborated into a preliminary design. Presenting an overview of the marina’s facilities, including structural designs, operational needs, and capital costs. Finally, suggestions for future development
are provided, outlining the next steps to advance the marina to a next phase.

This thesis presents the design process of an active wire rope tensioner, a device designed for cranes, that serves two primary functions. Firstly, it increases the tension in the wire rope during spooling, ensuring neat and tight winding on the drum to reduce damage to the wire rope and cutting-in problems. Secondly, it reduces the required lower block weight, thereby improving the crane's load curve.

The research has commenced with a study of relevant background information and working principles. A thorough literature and patent review has followed, revealing a gap in the state-of-the-art of tensioning devices that both prevent cutting-in and reduce the required lower block weight. In the conceptual design phase, seven innovative concepts have been generated based on the literature review and current principles. These concepts have been assessed for their capability to meet the requirements and their performance against the key performance indicators (KPIs). Consequently, five concepts remain, with the clamping track concept emerging as the most promising.

The clamping track concept utilizes a chain drive with clamps attached to it that press on the wire rope. By applying force to the chain, the tension in the wire rope can be manipulated. Detailed development of the clamping track concept has yielded a conceptual design with three potential deployment scenarios, each requiring a slightly different version of the active wire rope tensioner and offering distinct advantages and disadvantages. Scenario 1 offers the greatest possible lower block weight reduction but comes with the cost of a more complex and riskier system. Scenario 3 does not allow for any lower block weight reduction but is simpler and safer. Scenario 2 strikes a balance between the two.

This thesis presents the optimization of chord-bracing connections (tubular joints) in lattice boom structures using Wire Arc Additive Manufacturing (WAAM). The research aims to enhance the static and fatigue performance of critical joints, with a focus on the 1600mt LEC crane boom, which is used for offshore wind turbine installation. Through the integration of topology optimization and WAAM, the study seeks to improve structural efficiency by optimizing weld geometry and material distribution.
Finite Element Analysis (FEA) was employed to identify high-stress regions within the tubular joints, followed by topology optimization to refine their design. The study also investigates the impact of WAAM on material efficiency, fabrication flexibility, and the overall mechanical properties of the joints. The results demonstrate that the optimized tubular joints exhibit significant improvements in fatigue life and static strength compared to traditional designs, providing a more robust and cost-effective solution for lattice boom applications.
The findings of this research contribute to advancing the use of additive manufacturing in structural engineering, particularly in enhancing the performance and sustainability of offshore crane systems. The proposed optimization framework and design methodologies offer valuable insights for future applications of WAAM in heavy-duty structural components.

Fused Deposition Modelling (FDM) is one of the most popular 3D printing technologies because of its affordability and accessibility. FDM, however, often suffers from printing errors that result in wasted time, materials and energy. To address these challenges, this thesis introduces a novel fault detection system for FDM printers. This system is designed to identify a broad range of errors without interrupting the printing process. To achieve a real-time detection system, an innovative multi-camera setup is designed, integrating two side cameras and one nozzle camera. Our hypothesis is that a system including three cameras can provide a more comprehensive view and can ensure more error types to be detected. Error detection is achieved using Convolutional Neural Networks (CNNs). This is a type of machine learning that excels at image recognition and pattern detection, making it well-suited for identifying printing errors in real-time models. Two CNN models are developed to classify images into common 3D printing errors: one model for the nozzle and another for the side cameras. The models were trained and validated on diverse datasets containing various shapes, infills, and augmented data. The nozzle camera model achieved a high validation accuracy of 97.68% with a low loss of 0.07464. The side camera model achieved comparable performance with a validation accuracy of 97.61% and validation loss of 0.1196. These two well performing models were for the first time ever integrated into a unified fault detection system based on a logic-driven priority framework. From this research, we learned that integrating multiple viewpoints into a logic-driven priority framework significantly improved the robustness of error classification, as many more error types could be detected in-situ and real-time. As a result, the integrated system successfully detected 12 common printing errors. In summary, this work shows the feasibility of developing a robust multi-input fault detection system to improve 3D printing. It paves the way for further research and implementation for complex integrated error detection and correction mechanisms.

This thesis presents a model-based design framework for incorporating mechanical intelligence into soft robotics. By integrating smart materials with morphing structures, the framework enhances the adaptability of soft robotic systems. The embedded mechanical intelligence enables the synchronization of multiple smart materials, facilitating self-actuation and customized deformations. This approach advances the development of autonomous and adaptive soft robotic systems.

The global energy sector is increasingly shifting towards sustainable solutions, driving the expansion of offshore wind farm installation to meet rising energy demands. The upcoming wind farms will be constituted of larger wind turbines, requiring larger monopile foundations. The monopiles are typically installed using impact hammers that blow several strikes until the monopile reaches a specific penetration depth. The installation process generates high underwater noise levels, posing severe risks to marine life, including hearing loss, behavioral changes, and even death.

Existing noise mitigation systems struggle to attenuate low-frequency noise below1000 Hz due to the mass law limitations of natural materials. This thesis proposes a design methodology for a novel metamaterial-based noise mitigation system–the meta-cushion–designed to brake this limitation. Placed between the monopile and the hammer, the meta-cushion filters out mechanical waves generated by the hammer’s blow that cause high underwater noise levels. The design methodology ensures adaptability to various monopile installation specifications, facilitating the implementation of the meta-cushion in real world pile driving cases.

The thesis begins with an analysis of underwater noise during pile driving and the limitations of existing mitigation solutions, emphasizing the need for novel approaches to reduce low-frequency noise. The analysis shows a strong relation between high underwater noise levels and the low-frequency vibrations of the monopile caused by the hammer’s blow. Then, the concept of metamaterials is introduced, highlighting how their unique properties contribute to reducing low-frequency vibrations. Based on the understanding of the underwater noise-vibration relationship, an initial meta-cushion design exhibiting such filtering features is defined.

The numerical modeling of the meta-cushion is then detailed, with finite element analyses being conducted to investigate the behavior of the meta-cushion when interacting with mechanical propagating waves. The attenuation capabilities are evaluated via analysis of dispersion-curve and transmission loss diagrams. To ensure both mechanical integrity and noise reduction under impact loads, a design optimization strategy is developed, from which genetic algorithm is used to investigate the trade-off behavior between mechanical and attenuation performances. Once verified, the meta-cushion’s functionality is experimentally validated through modal impact analysis and small-scale pile hammering tests, demonstrating effective noise reduction at frequencies below 1000 Hz as also indicated by the numerical results.

Finally, this thesis presents a systematic design methodology–encompassing meta-cushion design selection based on pile specifications, numerical verification, and experimental validation–that can be adapted to full-scale monopile installations. By integrating the meta-cushion into offshore pile driving operations, this work contributes to mitigating underwater noise and its environmental impact.

This thesis describes an investigation in the modeling and manufacturing of Nitinol (NiTi) superelastic metamaterials. To achieve an accurate agreement between model and experiment regarding superelasticity in Ni-rich NiTi metamaterials, the research focuses particularly on the martensitic transformation behavior. Each chapter contributes to a better understanding of the entire additive manufacturing process chain, including constitutive modeling, heat treatments and structural design, to develop NiTi-based metamaterials with tunable superelastic properties.
NiTi shape memory alloys exhibit unique shape memory effect (SME) and superelasticity due to reversible martensitic transformations. These properties make NiTi a suitable material for adaptive structures, biomedical devices, and aerospace components. Though computational models can be used to design NiTi structures and metamaterials with superelasticity and SME, the successful additive manufacturing of these designs remains challenging. Achieving full superelasticity in complex geometries produced via laser powder bed fusion (L-PBF) is particularly difficult. Thus, aiming for model-experiment consistency of superelastic metamaterials, the main research gap lies in establishing clear qualitative and quantitative relationships between material models, properties, mesoscopic structures and the resulting macroscopic responses.

In Chapter 3, the research started with the development of analytical expressions for the effective transformation stress and numerical models to evaluate the superelastic behavior and energy dissipation of truss-based metamaterials. NiTi truss-based metamaterials with body-centered cubic (BCC) and octet structures were selected to represent bending- and stretching-dominated architectures, respectively. A detailed parametric finite element analysis was performed to study the relationship between relative density and effective transformation criteria. Using L-PBF, crack-free BCC and octet samples were successfully fabricated from Ni-rich NiTi powder. However, the as-fabricated samples exhibited only partial superelasticity and premature fracture.
In Chapter 4, the study is focused on inhomogeneity of microstructural and functional properties and the underlying reasons for partial superelasticity. Through both numerical and experimental approaches, the study investigated how geometric factors, such as relative density, affect microstructural inhomogeneity and thermomechanical properties of NiTi in body-centered cubic (BCC) structures. Geometric effects on melt pool behavior lead to different solidification textures and inhomogeneous response to indentation. The numerical simulation shows that inhomogeneous transformation temperatures cause narrow stress hysteresis in the macroscopic response. This chapter reveals the interdependent relation between relative density, microstructure, localized properties of NiTi and the macroscopic response.

The focus in Chapter 5 is on understanding and mitigating premature fracture in Ni-rich NiTi metamaterials produced by L-PBF. To investigate the origins of fracture, a comparative analysis of two unit cell architectures, the a Gyroid network (bending-dominated) and a Diamond shell (stretching-dominated), was conducted. Due to the inherent tension-compression asymmetry of NiTi, the structural stability of these designs was found to be reversed compared to conventional elastic-plastic responses, leading to premature fracture and limited superelasticity in the as-fabricated samples. As large deformation can not be achieved through martensitic transformation or dislocation slip systems, partial superelasticity and low deformation recoverability were observed in the as-fabricated samples. Heat treatments were applied to address these issues and achieve qualitative agreement between experimental data and model predictions.

After the superelasticity was successfully achieved, the transformation stress-temperature relation and energy absorption in Ni-rich NiTi superelastic metamaterials were investigated in Chapter 6. Temperature dependence often restricts the practical use of superelasticity. In metallic metamaterials, energy absorption typically relies on the elastoplasticity of ductile metals; however, achieving energy absorption with recoverable deformation has not been fully explored. To address this, a numerical model of the Diamond shell structure was developed to predict temperature-dependent superelasticity and energy absorption. A heat treatment was applied to ensure agreement between the model and experimental results. The findings show that the transformation stress-temperature coefficient decreases from 9.5 MPa/°C for bulk samples to 0.9 MPa/°C for Diamond samples. Under uniaxial compression, the effective transformation stress can be controlled by relative density, with values of 41.8, 52.1, and 65.3 MPa for relative densities of 0.15, 0.2, and 0.25, respectively. A specific energy absorption of 3.5 J/g was achieved in cyclic compression tests with 15 cycles. The recoverable plateau-like response in the macroscopic stress-strain curves originated in a continuous transformation region forms along the macroscopic [100] direction under uniaxial compression. Post-yielding plasticity in the macroscopic stress-strain curves is related to a plastic shear band formed along the [110] direction.

In summary, this work successfully developed a model-manufacturing strategy for superelastic NiTi metamaterials. By addressing multiscale challenges such as microstructural inhomogeneity and tension-compression asymmetry, this study demonstrates that computation-based design and additive manufacturing can create functional NiTi structures with tunable thermomechanical properties. Multiscale issues often prevent computational designs from being fully realized in experiments. By identifying and controlling variable interdependencies across scales, this research achieves largely tunable superelasticity in experiments. This approach provides a foundation for practical applications of NiTi metamaterials in fields such as biomedical devices, aerospace, and civil engineering.

This masters thesis investigates the influence of various printing parameters on the shape memory effect of 3D printed objects, with a focus on fixity and recovery rates. Through a series of experimental tests, it was observed that printing temperature had minimal impact on fixity and recovery rates. However, correlations were identified between fixity rate and layer height, as well as between percentage infill and recovery rates. Lengthwise shrinkage, particularly prominent in samples with 0\% infill, was attributed to printing speed the formation of voids within the structure and layer height. Higher printing speeds were found to compromise mechanical properties while facilitating enhanced shape transformation responses. Additionally, changes in layer height led to observable alterations in the printed object's geometry, including bending and bulging, due to retained shape memory of the filaments original form. Moreover, certain 100\% infill samples exhibited an unexpected hardening phenomenon akin to annealing. These findings underscore the intricate interplay of printing parameters in determining shape memory properties, mechanical properties and highlight potential avenues for optimization in 3D printing processes.

Flexible robotics offers promising solutions for navigating complex environments, and this study contributes to its advancement through innovative methodologies optimizing both flexible robotic arm kinematics and a novel flexible actuator. The first methodology focuses on optimizing kinematics using quadratic programming, enabling the determination of optimal segment configurations without prior knowledge of specific materials or working principles, thus introducing a novel systematic first step in flexible robotic design. Addressing computational intensity and solver compatibility limitations, valuable insights are provided into designing segmented flexible robotic arms, offering a systematic methodology for real-world challenges. Simultaneously, an electromagnetically actuated Kresling cylinder is introduced, leveraging tunability in axial stiffness and electromagnetic actuation. Through dimensional optimization using finite element analysis (FEA), critical design considerations such as coil dimensions and core configurations are systematically explored. Experimental validation extends the application to full-sized robotic arms for package unloading in confined spaces, underscoring the significance of magnetic force in overcoming gravitational resistance, especially in logistics environments. These methodologies represent significant contributions to the field of flexible robotics. The first provides a systematic framework for kinematic optimization, while the second introduces an innovative actuation mechanism tailored for flexible robotic arms in industrial settings requiring long-reach capabilities. Their integration opens new possibilities for designing adaptable robotic systems capable of complex tasks in diverse environments. By addressing computational challenges and practical constraints, this research advances the frontier of flexible robotics, facilitating real-world implementation across various industries.

This thesis explores the fabrication of biomimetic shark skin, focusing on actively controlling the bristling effect of denticles, inspired by the passive bristling effect observed in the skin of Shortfin Mako sharks. By examining the natural structure and functionality of shark skin, the research aims to replicate its unique properties using innovative fabrication techniques. A review of previous methods for replicating shark skin structures led to the selection of an indirect fabrication approach, driven by the necessity to integrate an actuation mechanism. Drawing inspiration from soft robotics, the study identified Nitinol, a shape memory alloy, as the optimal material for actuation due to its significant force exertion and seamless integration into the silicone shark skin.
Experiments were conducted in a water tank, testing various configurations of biomimetic shark skin to evaluate the performance of the integrated actuation mechanism. The initial findings demonstrated that Nitinol wire actuation within a silicone matrix effectively mimics the bristling mechanism, even in aquatic environments, showing sufficient strength to counteract water flow. While this research successfully demonstrated the feasibility of integrating actuation mechanisms into biomimetic shark skin, further studies are necessary to optimize the design for practical applications.

In mechanical systems, energy efficiency is often reduced by unwanted forces like friction and backlash, which significantly impact performance and, over time, lead to increased wear and maintenance costs. Implementing compliant joints can address these issues, simplifying assembly and improving performance. However, compliant mechanisms introduce higher internal loads due to elastic deformation in the flexures, limiting the range of motion and affecting overall efficiency. One way to solve this is using the principle of static balancing, which ensures that a point of interest remains in equilibrium, meaning that no added forces or moments are needed to keep it at rest at certain positions. This can be done by compensating the internal potential energy, which has been implemented in literature for 1 Degree of Freedom configurations. The goal of this paper was to expand the known method into designing a multi-degree of freedom without the use of external springs. The method was based on applying a preload to the compliant joints in the mechanism and optimize in such a way to create a constant potential energy curve. The model was validated using finite element analysis, prototyping and physical testing. It can be concluded that for the first time, a two degree of freedom statically balanced mechanism has been designed. It has a peak force reduction of $95\%$ and a moment reduction of $80\%$, while having a range of motion worth $50\%$ of the size of the mechanism. The mechanism can be used in vibration isolators or as fundamental inspiration for new applications where preloading could lead to lower exerted loads and thus improve efficiency.

The importance of natural environments with rugged deformable terrain (marshes, mangroves, rainforests, coastlines) from biodiversity, carbon capture, and coastal protection to economic livelihood is significant. However, the current systems available for robots to explore those ecosystems are either large, expensive and intrusive, not application focused or consist of custom components that are difficult to integrate with existing robotic mechanisms. This thesis proposes a novel soft adaptable wheel suited for such ecosystems. The mechanism operates as a fluidic elastomer actuator constructed with Dragon Skin 30 able to change its form depending on the task at hand. Various designs were simulated in MuJoCo to test its ability to overcome rigid obstacles and terrain forms (from ramps, steps, smooth undulating terrain and terraced undulating terrain). The design's structural feasibility was then tested and further improved using Ansys with the final result having a loading capacity of 1.25N (at 0kPa) and a maximum blocked force of 1.98N (at 35kPa). Finally, the wheel was tested at 3 distinct operating configurations (neutral, partial and fully inflated) in 4 types of deformable terrain (non-compressible dry, compressible dry, non-compressible sticky, compressible sticky) using EDEM Altair. This evaluated its performance and validated the need for different forms according to the rheological properties of the terrain. The design proposed in this paper is intended to be more application-focused, with its simplicity facilitating integration into robotic systems, using off-the-shelf components, and ultimately reducing the time required to be used in environmental applications.

The escalating global demand for poultry products, coupled with the challenges of securing personnel for the often arduous tasks in poultry processing plants, has underscored the urgent need for automation in this sector. The inherent variability and delicate nature of poultry products, like chicken fillets, pose significant hurdles for traditional automation solutions. This research seeks to address this challenge by employing simulation-aided design to develop an automated solution for singulating and orienting chicken fillets. The study investigates existing technologies in poultry and other food industries and develops a practice-oriented Discrete Element Method (DEM) model to simulate chicken fillet behaviour. The model's efficacy is validated through a series of tests, including damping, bending, sliding, sensitivity analyses and real-life experiments. The insights gained from these simulations inform the design of an automated solution, which is then iteratively refined and visualised in the DEM software. The proposed solution successfully demonstrates the potential of simulation-assisted design to automate complex tasks within the poultry processing industry, paving the way for increased efficiency, productivity, and reduced reliance on manual labour. The research also underscores the importance of considering the unique characteristics of poultry products in developing effective automation solutions, highlighting the need for further exploration into advanced modelling techniques and material and interfacing equipment behaviour analysis.

This research aims to design and simulate a hinge consisting of shape-memory alloys and polymers, which can be actuated along two axes. The hinge consists of a shape-memory body that is actuated externally by shape-memory alloy springs. To achieve maximum deformation, two small single hinges are made, of which the body has the shape of a plate and which are actuated externally by two springs. The two hinges are then stacked, where the second hinge is twisted 90 degrees, so it can move in two directions. Tensile tests of Nitinol wires were carried out to investigate the behavior. Shape-memory springs were manufactured with this Nitinol wire. Then, the springs were deformed, the temperature of the springs was increased in steps of 10 degrees C, and the force was measured at each temperature step. Simulations were also carried out and compared to the force tests. The best type of Nitinol was chosen for the shape of memory wires. A prototype of the hinge was built and tested. First, the small single hinges were tested, where the displacement was documented. The hinge was not deemed energy efficient. Finally, simulations were carried out for the single and stacked hinges, which showed that the results were similar to reality. Hereafter, the range of motion of the stacked hinge is determined.

mart materials are already often used as actuator or sensors, as well in soft grippers as other fields. However, the application of thermoresponsive smart materials as actuator is still a potential field. As electroactive polymers and shape memory alloys are commonly used thermoresponsive smart materials for actuators in soft grippers, a novel design will contribute to this area by adding a new potential field: soft grippers actuated by thermoresponsive hydrogel particles. A structure, filled with thermoresponsive hydrogel particles which will swell after decreasing the temperature, will act as a gripper. After considering the relevant
parameters of soft grippers for this research, multiple demo structures are manufactured and compared with simulations. Additionally, the effect of these parameters on the bending performance is determined with
a Design of Experiments. At last, a potential configuration of a multi segmented adaptive soft grippers is presented.

The demand of offshore wind energy has increased enormously in the last decade, and continues to do so in the foreseeable future. The monopile will remain the most important foundation structure. There is however not yet a durable solution for its main disadvantage; the under water sound radiation during installation. In this report a new, silent installation method is therefore explored: screwing monopile into the ground. In this thesis the interaction between the monopile and soil is explored, along with the addition of a screw thread. Based on this the driving requirements are determined. Then a possible driving mechanism is shown, considering the driving power, connection between the ship and the monopile and driving equipment. Lastly, the implications of the logistics is explored.

The success of offshore wind farm installations is often related to the costs and time taken to be completed. Current installation strategies require several critical offshore lifts for the completion of a single wind turbine, as in most cases each component gets installed separately. This is time-consuming and has a direct link to the cost of the operation. Therefore trying to find more efficient methods of offshore wind turbine installation should be one of the main focuses in the industry. A possible solution to the problem involves the single-lift wind turbine installation. For this method, the whole wind turbine is pre-assembled and lifted onto the offshore foundation with one lift. This way the number of critical lifts offshore is reduced, which has the potential to reduce overall installation time and cost. The downside of this method is that, for the lifting of a whole wind turbine, very calm environmental conditions are required, leading to low workability. Calm environmental conditions do not often occur at offshore wind farm locations, and hence, solutions to improving the workability of this particular method are required to make it competitive with current installation methods.

The solution proposed in this thesis is to utilise the Upper Stabiliser Frame (USF), a Heerema Marine Contractors concept, which helps to eliminate unwanted motions of the wind turbine while in the air. The frame gets mounted at a height on the tower above the combined centre of gravity of the whole wind turbine. Since this frame is only a concept, its exact effect on the installation has not yet been studied in detail, and the actual design of the frame has not yet been fully developed. Therefore, the aim of this thesis was to analyse the loads experienced by the whole system (floating vessel and wind turbine) during such an installation and to investigate how the USF frame could be designed to constrain the relative rotation between the tower and the USF.

To reach the objective of the thesis, various analyses were conducted in LiftDyn, an in-house Heerema software, and OrcaFlex, where the whole system, or parts of the system, were investigated. A modal analysis and frequency domain analysis were done in LiftDyn while time domain analyses of different environmental loads were performed in OrcaFlex. The response of the system was examined, and based on the results, the maximum yaw moment acting on the tower under limiting environmental conditions was determined.

The results of the investigation showed that the WTG motions are limiting for safe operation and lead to very low acceptable environmental conditions compared to other installation methods. Based on these conditions, the maximum tower yaw-moment recorded was 2100 kNm. This moment was transformed into a tangential force acting on the tower, which the frame had to counteract. Two possible designs of the USF, both utilising friction, were created. The first design consisted of friction pads spaced around the circumference of the tower, while the second used a band brake to deliver the necessary friction. A multi-criteria analysis with weighted factors was conducted to evaluate which design performed better. Based on this analysis, the band brake design showed better performance, making it the most suitable design for the USF.

The novel concept of the single lift installation strategy with the USF is still not ready to be used yet for real projects and will require further development to become competitive with currently used strategies. This thesis has formed the basis for further research in the field by identifying key problems that must be resolved and suggesting innovative solutions for the USF design. This installation strategy has the potential to revolutionise wind turbine installation by decreasing installation time, increasing operational efficiency, and in general, streamlining the whole process.

Huisman has introduced the Windfarm Installation Vessel as a complete solution to assemble and install offshore wind turbines at sea.
Installing a floating wind turbine at sea brings two main challenges, the relative motions between the floating structures and the load transfer of the wind turbine.
The proposed installation procedure considers a connection between the installation vessel and a semi-submersible floating support structure to reduce the relative motions and facilitate the load transfer.
This research investigates how the connection's structural configuration affects the system's relative motions and loads during five defined installation stages.
The different installation stages cover varying amounts of ballast transfer, as well as the mating phase of the wind turbine.
A two-dimensional multi-body model has been formulated considering a rigid link between the installation vessel and the floating support structure.
The hydrodynamics of the floating structures and the regular wave loads on the structures are calculated using Ansys AQWA.
A system analysis is performed to investigate the effect of adding stiffness in one or combined directions of motion of the connection.
The change in dynamic effects during the installation stages are minimal, the ballast transfer mainly changes the static load on the connection.
Overall, it can be concluded that a combination of stiffness in the different connection directions will provide the most favourable results.
To limit the relative heave motions, coupled surge or pitch and heave stiffness is required.
A different stiffness on both sides of the connection is also shown to improve the system’s behaviour.
Fixing the rotation of the connection on one side improves the relative pitch motions between the wind turbine and the support structure.
More research is required to investigate favourable combinations of limiting motions on each side of the connection.
The presented model could be used for a future optimization study to find optimal stiffness values for the connection.