The maritime sector is under pressure from emission reduction regulations resulting from climate laws such as Fit for 55. With the introduction of the FuelEU Maritime regulations, which have been active since 2025, shipping companies and fuel traders are confronted with new requirements and complex decisions to reduce emissions. Solutions include retrofitting and switching to low-carbon fuels. These regulations will also indirectly impact fuel suppliers and traders, as demand for alternative fuels and strategies will increase.

Regarding the above, larger companies have the resources and capacity to respond and adapt adequately. For smaller and medium-sized companies, there are barriers that hinder or delay the transition. It is important that fuel companies also participate in the transition. Within fuel and bunker trading companies, there are traders who can play an important role as intermediaries in promoting low-carbon transition fuels. However, traders also face obstacles in communicating about sustainable fuels and regulations.

Therefore, this research focuses on the development of a digital tool that can support traders in communicating fuel options more effectively and stimulate informed decision-making towards the adoption of low-carbon transition fuels among shipping companies. A digital tool can positively influence and facilitate substantive communication and understanding between both stakeholders. The research project follows an iterative Double Diamond Design process divided into phases.

The project started with an in-depth exploration of the context, internal processes, regulations, (behavioral) barriers, and drivers among the main stakeholders. This highlighted bottlenecks such as uncertainty or the lack of knowledge and tools. But it also showed opportunities and strategies that could be implemented to stimulate communication and adoption, such as nudging strategies, intervention moments and the need for stakeholder collaboration.

Based on the insights gained, a design scope has been established, and a design vision has been defined that offers direction and constraints for the project. From that, concrete design goals and requirements have been formulated to encompass all needs and design choices.

These principles translated into 3 envisioned scenarios (standard relationship processes between stakeholders), from which associated concept ideas emerged for a calculation tool that provides strategic insight into fuel, compliance, and costs.

These concept ideas were tested with traders and found useful, effective, and strategically valuable. Traders expressed a need for a flexible and effective tool with clear insights that supported various customer interaction moments regarding sustainability, costs, and compliance.

After this validation and further insights, a final concept tool was developed with additional materials such as a toolkit, roadmap, leaflet, and mail report. All are designed to ensure the implementation and communication of the tool and its adoption, and to maximize impact. The tool is designed to meet the process and interaction needs of stakeholders. It enables fast and low-threshold scenario analyses and strategic decision considerations. In addition, it stimulates and improves stakeholder relations, makes benefits visible, minimizes barriers, and can be utilized in multiple usage scenarios.

The tool offers a scalable foundation for future digital solutions supporting informed communication and decision-making about sustainable fuel choices in the maritime sector.

Wire arc additive manufacturing (WAAM) is attributed to higher material deposition rates and medium to large build volumes. Integration of multi-axis (more than three) material deposition kinematics in WAAM can bring a paradigm shift in the metal additive manufacturing industry. The material build-up mechanism employing directed energy deposition results in localized melting and solidification of feeding wire making the fabricated structure inherently prone to deposition defects such as dimensional distortion, residual stresses, solidification cracking, and porosity. Optimization of welding process parameters can improve cracking and porosity behavior. However, the problem of distortion is inevitable, and current mitigation strategies rely on post-processing or symmetric material deposition; while the former decreases the effectiveness of WAAM and increases costs, the latter could only be implemented for specific parts. Tackling this problem with the help of computational design tools is a recent approach, and Fabrication Sequence Optimization dictating material deposition is numerically predicted to limit the extent of the distortion effectively compared to conventional planar horizontal deposition; however, this still lacks experimental validation. This research presents a series of fabrication experiments using Al5356 Aluminum-magnesium alloy wire in a 6-axis robotic WAAM setup in two parts: (1) Process parameters identification for optimal bead characteristics for Al5356 wire, (2) Fabrication of single-bead multi-layered thin-walled shell structures using planar and optimized material deposition. A digital image correlation-based non-contact in-situ distortion measurement setup is constructed to analyze strain development during fabrication process and 3D scanning of fabricated structures is performed to estimate dimensional deviation. The experimental findings revealed an improvement in geometrical formation and a qualitative indication of distortion minimization with an optimized fabrication sequence.

Wire Arc Additive Manufacturing (WAAM) is a manufacturing technique with the ability to produce large metal parts with relatively complex geometrical shapes. One obstacle limiting full exploitation of WAAM in the industry is uncertainty on the mechanical properties of manufactured parts. Mechanical properties are strongly influenced by the microstructure of the material which is a product of the thermal history of the material. Thermal history of parts manufactured with WAAM is complex which leads to uncertainty on mechanical properties and microstructure. Therefore a methodology to predict thermal history, microstructure and hardness of metal-based additive manufactured parts is presented, validated and applied in this study. The methodology is applied to high strength low alloy s690 steel parts produced with WAAM. First a part level thermal process model is utilised to predict the thermal history. Subsequently, a model is developed to predict the microstructure by modelling microstructure phase transformations. Based on thermal history and microstructure phase fractions, Vickers hardness is predicted. Predictions are validated with experimental measurements and observations obtained from a collaborating master thesis. Part temperatures of the thermal model agreed well with measurements. Although the predicted microstructure phase fractions show a lower ferrite content than experimentally observed, the trend of the microstructure phase fractions along the part height is the same in the prediction and the experiment. The predicted hardness is 49 HV higher than the measured hardness. However, hardness predictions and measurements show the same trend along the part height. The methodology to predict the thermal history, microstructure and hardness was applied on a study in which the height of a wall was varied and on a study on a geometry in which two walls cross each other at the center. For both studies the martensite content decreases over the part height, whilst the bainite content increases over the part height. This is caused by the decrease of cooling rate over the part height. Hardness also decreases over the part height. For both the change in microstructure phases and the hardness over the part height, the largest change was observed at the bottom of the part. For the study with the crossing geometry, no significant difference was found for the microstructure and hardness between the center and side of the crossing.