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Senast publicerade

Ultrasonic Signal Response from Internal Manufactured Defects in Laser- Based Powder Bed Fusion (PBF-LB) Manufactured superalloys
(2026) Surendran, Anupama
Additive manufacturing (AM) is an advanced technology reshaping global product fabrication by enabling lightweight and complex structures directly from CAD models [1]. While AM provides design freedom and material efficiency, challenges remain in ensuring consistent quality, as defects such as porosity, microcracks, and lack of fusion (LOF) voids can degrade mechanical performance [7–9]. Non-destructive testing (NDT) methods are therefore critical, with X-ray Computed Tomography (XCT) and Ultrasonic Testing (UT) emerging as the most promising despite limitations of cost, speed, and geometry sensitivity [16,20]. UT, in particular, enables early detection of internal flaws without damaging the component, and recent advances such as phased array and laser-based techniques are expected to further enhance inspection capability [2,24,25]. This study evaluates the ultrasonic signal response from intentionally introduced defects in PBF-LB manufactured Alloy 247 and Inconel 939 samples. Both immersion UT and PAUT were applied to investigate the influence of defect morphology, orientation, and surface finish. Results showed that defects down to 0.4 mm could be reliably detected when oriented perpendicular to the scanning surface. Machined surfaces significantly improved defect detectability, while partially melted powder around defects increased scattering and reduced signal clarity. Among probes, the 3.25" transducer provided the most consistent response due to its larger aperture, which enhanced beam focus, signal strength, and defect detectability across varied geometries and surface conditions. Defect morphology strongly influenced detectability, with angled and roof-shaped defects showing reduced visibility compared to cylindrical or spherical ones. Comparison of inspection methods demonstrated that PAUT enhanced sensitivity and imaging in geometrically complex regions, whereas XCT provided more accurate defect characterization but with slower scan speed and higher cost. These findings highlight the importance of probe selection, surface condition, and defect morphology for developing robust in-situ inspection strategies and support the integration of PAUT and XCT as complementary methods for standardized quality control in metal additive manufacturing.
Body design of electric three-wheeler
(2026) Romell , Joakim
Electric three-wheeler manufacturer Omotion, located in Lund, Sweden, was in the process of improving the performance of their only existing vehicle model, the Omotion 2. A new vehicle model was desired in which the performance increase could be implemented. Omotion wanted to achieve a “modern” and “sporty” design which utilised the performance efficiently. Aerodynamics was therefore a concern. Included in the requirements was that the design had to have a roof over the occupants. As a roof was a necessity, how individuals enter and exit the vehicle was considered in the work. Because the work was very aesthetics driven, aesthetic trends for motorcycles and sportscars in several Western European countries were studied. Naked and adventure motorcycles were determined to be trending and consisted of features such as exposed mechanics and small complex bodywork panels. Sports cars shared similarities such as low to the ground and slightly sloped hood. A function analysis was also done as part of the prestudy and guided the concept development. The function identified were kept vague to allow for a wide variety of solutions. Concept development was done with the help of sketches, morphological matrices, CAD models, and a clay model. Concept generation was also attempted using artificial intelligence (AI) but was unsuccessful. The work resulted in a satisfactory concept despite difficulties ascertaining the aerodynamic performance. Mechanical solutions to make the concept feasible would still be developed but the mechanisms were already in use on other vehicles. With continued development of the concept, Omotion should have the ability to realise the concept within ten years
Integrated Fast Battery Charger Using an Electrically Excited Synchronous Machine-Based Drive System
(2026) Ma, Xinyu
This thesis investigates an integrated off-board fast battery charging system utilizing an Electrically Excited Synchronous Machine (EESM)-based drive topology. The aim is to reuse the existing traction inverter and machine windings as part of a DC/DC boost converter, thereby reducing system cost, volume, and component redundancy. To achieve this goal, three levels of simulation were carried out. First, an excitation-based Finite Element Analysis (FEA) in ANSYS Maxwell was per formed to determine losses and inductances of the EESM under various operating conditions. Second, a system-level co-simulation between Maxwell and ANSYS Simplorer/Simulink was conducted, in which the electromagnetic model of the machine interacted dynamically with the converter and control system. This enabled real time calculation of inductances and losses under variations in both shift angle and rotor position. Finally, a Simulink-based system simulation was carried out to analyze current ripple, torque generation, and efficiency across different frequencies. The results show that phase-shift modulation predominantly affects the current waveform and ripple behavior, while the magnetic coupling and inductance remain almost constant. Increasing the switching frequency reduces stator core losses but has minimal impact on copper losses. Overall, the proposed integrated EESM-based fast charger demonstrates high feasibility and efficiency. It achieves compact system integration, stable electromagnetic performance, and effective control of current ripple and core losses - offering a sustainable approach for future electric vehicle charging architectures.
Our future through a film lens: A speculative exploration of the future’s architecture based on today’s development plans & films
(2025) Lennartsson, Nadja
The future city consists of tightly built high buildings, so the sky is barely visible. People will no longer eat food, but rather take pills, and the traffic will be moved to the air. Everywhere you go, there will be some sort of technology, and society relies on AI. Natural disasters are more common with greater effects and more problems in the utopia arise. The dream people once had has turned into a nightmare. The thesis speculated and explored the future of Gothenburg, which was shown in a final film. Today, architects don’t use the art of storytelling, but rather technical drawings to communicate their ideas, and the images they create are seldom emotionally affecting. On the other hand, films communicate a range of emotions that affect the viewers. In this thesis, storytelling and communicating emotions through hand drawings, aquarelle colouring and film in architecture is explored. By inspiration from films, architects can communicate emotions in architecture and enhance the experience of spaces. They can also take inspiration from films and other media to design buildings or reflect on our society’s architecture. How do film and museums communicate and portray dystopia and anxiety? What will Gothenburg look like every 25th year from today to 2125, based on the architectural developments happening today? Rosenlundsverket is a deteriorating building in Gothenburg with many layers that contribute to a dystopian appearance. By an analysis of five films, this thesis discovers how time, colour, light and shadow can communicate emotions and how those strategies can be applied to buildings. That results in a reconstructed version of the building that metaphorically is our distorted future. The analysis consisted of watching films, choosing particularly emotional scenes, sketching them and placing them on a timeline. They were then analysed to determine how they portrayed and evoked emotions such as anxiety. Based on the analyses and research about utopia, dystopia and filmmaking, perspectives of the Rosenlundsverket’s rooms were painted. The perspectives of the utopian and dystopian rooms were then assembled into a film. The tools learned from the explorations were then used when creating and materialising my personal view of the future Gothenburg city, which was lastly shown in a film.
Introducing the ModularML Framework - A transparent and modular machine learning framework made as a tool for research and education
(2025) Norland, William; Bremer, Måns; Sättemo, Gabriel; Carlsson, Sander; Nilsson, Elias; Carlsson, Tim
This thesis explores the process of creating a highly modular machine learning framework in C++, without performance compromises. The framework can parse ONNX models into dynamic C++ objects, modify the implementation of core computational functions (like GEMM), and use the models to perform inference. The framework reproduces results achieved in peer frameworks like PyTorch and TensorFlow. The usefulness of this framework stems from its pure C++ implementation, with no API layers to compiled modules or other black-box functionality. This makes it highly suitable for use in education and research, where debuggability, modularity, and ease of use are paramount.