Knowledge

Floating Power Plant (FPP) develops a hybrid floating wind and wave energy device. Pitching Wave Energy Converters (WECs) interact with the supporting structure, amplifying the motion of the WECs within the design wave frequency range. In this work we focus on the effect of the chamber geometry – without the WEC – in amplifying the waves inside the chamber. The simulations are carried out using two-phase Navier-Stokes simulations. We investigate the wave propagation and the interaction between waves and the fixed support structure. The simulations are compared to experimental tests performed in the wave basin at Aalborg University.

Offshore jacket foundations for wind turbine generators are in risk of metal fatigue at the weldedjoints due to the highly dynamic wind and wave loading. The complex multiaxial stresses occurringat the welded joints can be non­proportional and lead to increased fatigue damage as compared toproportional stresses. Furthermore, several random effects influence the response of the offshorestructures and the fatigue lives of the welded joints.

In this thesis, the fatigue response of welded joints in offshore jacket structures is assessed. The influence of non­proportional stress states on the fatigue life has been examined using experimental fatigue data from literature by modelling the published experiments using the finite element method (FEM) and assessing the stress states using the notch stress approach. The results show that a nonzero phase­shift between the governing normal and shear stress at the weld toe leads to increased damages at the weld. An approach for determining the non­proportionality penalty factors for obtaining correct fatigue life estimations has been proposed.

To quantify the level of non­proportionality in the stress states at welds a new quantification approach has been developed based on the principal component analysis (PCA). The approach is easy to implement and simple to interpret, which is often difficult for many of the already published methods. The PCA­based approach is furthermore extended to be used with variable amplitude stress states. By implementing the developed quantification approaches in the fatigue life calculation framework, it is possible to determine if non­proportionality occurs and to account for this in the fatigue life estimation automatically using the estimated penalty factors.

The stochastic finite element method (SFEM) has been used to implement approaches for considering the spatial variability occurring in the jacket structures and welds. Closed­form solutions to the stochastic stiffness and stress stiffness matrices have been proposed, making it possible to easily implement the spatial variability of the bending rigidity and other parameters in beam FE models. The matrices have been developed for both classical Euler­Bernoulli and Timoshenko beam theory and are based on the Karhunen­Loéve (KL) expansion for random field discretization. The KL expansion is then further used to formulate a stochastic size effect that takes into account that longer welds tend to fail earlier than shorter welds when considering fatigue. Other approaches for taking into account the size effect are often based on statistical evaluation of fatigue experiments which is used to determine a deterministic calibration factor. The stochastic size effect makes it possible to simulate the randomness in a full weld independently of the highest stressed zones. Using this method, the quality of the welding can be simulated and used to predict more accurate fatigue lives.

In order to design more fatigue resistant welded joints in offshore jacket structures, automatic optimization of the welded joints is required. Already published approaches to do so, often focus on only a few simple fatigue criteria. For an optimization framework to be efficient it has to take into account the complex multiaxial non­proportional fatigue and the stochastic effects of the welds. In the thesis, an optimization framework for fatigue life estimation using the developed PCA­based quantifier and the stochastic size effect has been developed. The framework is easy to use and based on simple formulations, making it possible to implement many types of fatigue criteria without having to reformulate the optimization procedure. The framework has been used to optimize the weld locations in a cast steel jacket insert and shows that considerable mass savings can be achieved by automatic
optimization.

Physical wave basin tests with a focus on uncertainty estimation have been conducted on a sphere subjected to wave loads at Aalborg University as part of the effort of the OES Wave Energy Converters Modeling Verification and Validation (formerly, OES Task 10) working group to increase credibility of numerical modeling of WECs. The tests are referred to as the Kramer Sphere Cases, and the present note is dealing with wave excitation force tests on a fixed model. The present note is including details to facilitate CFD models which replicate the physical setup in detail.

Physical wave basin tests with a focus on uncertainty estimation have been conducted on a fixed sphere subjected to wave loads at Aalborg University as part of the effort of the OES Wave Energy Converters Modeling Verification and Validation (formerly, OES Task 10) working group to increase credibility of numerical modeling of WECs.
The present note defines an idealized test case formulated to accurately represent the physical tests in a simple way. The test case consists of a fixed, rigid sphere half submerged in water subjected to regular waves of three different levels of linearity. The objective of the present note is to allow for numerical tests of the idealized test case.

Floating Power Plant is, together with several partners, preparing to design, build and test a scaled version of the complete so-called P80 device. The scaled model is to be tested in AAU's wave basin, SSPA's facilities, followed by at least one external facility. The model will be tested in combinations of wave, wind and current conditions with a view to validating the numerical models and to further develop the understanding of the interactions within the device. The purpose of this document is to gather information that is relevant to designing and building the physically scaled model, and to designing and executing the test campaign.

The project "IEA OES Task 10 Phase III - WEC Modelling" is a publicly-funded research project under the Danish Energy Agency EUDP grant with Journal no. 134232-510153. As part of the initial period of the project, a selection of three test cases has been defined under WP2. The present report forms the deliverable for Milestone "M1: Case studies defined".

The capacity to act as a port state in international law is best described by the specific powers exercised over foreign ships, namely inspection, detention, expulsion or request of any type of information prior to the entry into the port. Many of these powers are explicitly attributed to the state in multilateral instruments, whereby the flag state consents to having its ships subject to the jurisdiction of the port state. Notwithstanding the consensus around the complementary nature of port state jurisdiction with respect to certain obligations of the flag state, the port state is not limited to fulfilling a secondary role. This is especially visible in the prevention, reduction and control of ship-source pollution, where some port states have not hesitated in acting regardless of an expressed consent by the flag state to the rule or standard being applied with the support of port powers. Not only do port states use more stringent enforcement powers to ensure that international treaties are effective, but they also prescribe novel rules and standards upon any foreign ship that approaches the port, often as a means of breaking an international negotiation deadlock. This study discusses the international legal basis for such unilateral jurisdiction by analyzing the principles of state jurisdiction under the dichotomy parochial/cosmopolitan. By interpreting the stated and implicit purposes of port state actions under that dichotomy, this study proposes that states are finding a legal ground to act based on certain legal functions they fulfill in the international legal order. This argument puts into perspective the assumed self-sufficiency of territoriality and shows how unilateralism may also serve to seek to set universally applicable norms.

The content of Resolution MSC.473(ES.2) can be summarized in five main points and one invitation to IMO Member States.

The first point pertains to the implementation of the Framework of Protocols. The second point pertains to the designation of seafarers as 'key workers' in order to facilitate safe and unhindered movement for embarking or disembarking a vessel. The third point pertains to the consideration of temporary migration measures to ease mobility of seafarers, eg waivers or relaxations of visa or documentary requirements. The fourth point is on the use of prevention measures such as testing crews before embarkation; this requires active conduct by port states, namely providing access to personal protective equipment and testing facilities. The fifth point is on providing seafarers with immediate access to medical care and facilities, as well as with evacuation when the assistance required cannot be provided on board or at port; this aims to prevent humanitarian situations such as casualties on board vessels due to lack of access to intensive care units.

Furthermore, the Resolution invites Member States to designate a National Focal Point on Crew Change and Repatriation of Seafarers ('National Focal Point').

The emissions of the maritime sector caused by ship transportation and other fossil fuel sources pose a threat to the environment and human health. It drives an increasing interest in adopting electrification solutions to revolutionize the conventional maritime energy-intensive and highly polluting industry. Accordingly, this thesis is one of the pioneering attempts to implement a seaport microgrid and carbon capture shore power system of cold ironing at a port dedicated to sustainability while remaining competitive.
However, the technological and research gaps of the conventional port scheduling paradigm constitute challenges in a synergy between the two prominent maritime electrification systems of seaport microgrids and cold ironing. The incorporation of cold ironing into seaport operations introduces new challenges to handling workflow and the potential impact of such integration has not yet been quantitatively addressed. Developing strategic management to improve port performance is always an issue for the port operators. This research gap motivated this study to develop an integrated operation and energy management framework by executing forecasting and optimization techniques for coordinating these technologies toward the emission neutrality goal.
This thesis begins with an extensive review of the significant aspects of cold ironing technology and seaport microgrids. A range of factors associated with the varying demand for cold ironing in seaport microgrids, requiring advanced forecasting techniques, are described in Chapter 2. Another challenge is that the integration of cold ironing with limited capacities increases the complexity of the existing seaside operation at port namely the berth allocation problem (BAP) and quay crane allocation problem (QCAP). It prolongs the waiting time for the ships to be served at berth. Thus, a seaside operational optimization model is developed in Chapter 3 to cooperatively schedule BAP, QCAP, and cold ironing assignment problems (CIAP). Chapter 4 integrates bilevel optimization as an energy management system (EMS) framework to coordinate the joint cold ironing with the seaport microgrid concept, providing more flexibility in energy scheduling while remaining cost-effective. Finally, Chapter 5 presents the overall conclusions of the thesis, research contribution, and future recommendations.

This book explores the transformation of Danish shipbuilding from 1975-2015. Specifically it expores the closure of B&W Shipyard in 1980, Nakskov Shipyard in 1986, Aalborg Shipyard in 1987-88, Burmeister and Wain Shipyard in 1996 and Danyard Frederikshavn in 1999. The author identifies 27 firms that were spun out during the closure of five Danish shipyards and finds that several of these firms were able to apply the inherent resources in new activities with more value added. The book also finds that the competencies of the redundant workers from the four shipyards were useful in other parts of the Danish labor market. The book sheds new light how internal and external factors influence the transformation of mature industries.