Examensarbeten för masterexamen
Länka till denna samling:
Browse
Senast publicerade
- PostThe Design, Optimization and Experimental Framework for Pressure Sensors(2024) Al Rawahi, Sabah; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Sun, Jinhua; Sun, JinhuaThis thesis explores the fabrication and optimization of thin-film pressure sensors (TFPS) using graphite (Gr) as the active material and polyvinyl alcohol (PVA) as the binder. Three TFPS samples were fabricated and tested under both lowpressure (below 800 Pa) and high-pressure (1 MPa to 5.5 MPa) conditions, with key performance parameters—sensitivity, limit of detection (LOD), response time, and stability—evaluated. Results indicated that the sensors demonstrated high sensitivity in the high-pressure range but exhibited limited sensitivity for low-pressure range. Sensitivity values in the low-pressure range were 6.8×10−5kPa−1±1.8×10−4kPa−1 2.1 × 10−5kPa−1±1.9 × 10−4kPa−1 and 3.4 × 10−5kPa−1±1.8 × 10−4kPa−1, while in the high-pressure range, they were 1.9 × 10−4kPa−1±2.9 × 10−5kPa−1, 1.6 × 10−4kPa−1±2.6 × 10−5kPa−1 and 1.5 × 10−4kPa−1±3.0 × 10−5kPa−1 for samples 1, 2, and 3, respectively. The LOD ranged from 6.6 × 10−2 kPa±2.8 × 10−2 kPa to 5.6 × 10−2 kPa±2.9 × 10−2 kPa in the low-pressure range and 1.7 × 10−3 kPa ±8.2×10−9 kPa to 2.0×10−3 kPa ±9.5×10−9 kPa in the high-pressure range. Stability tests suggested potential applications in health monitoring and insole pressure sensing. However, the response time (82 ms) of the fabricated sensors is relatively slow. Proposed improvements include the use of automated systems to reduce human error and alternative coating methods to improve film homogeneity. As well as, incorporating an additional component between the CCAF and the film to allow better stress distribution within the material; since the rigidity of the film promotes slippage between the CCAF and the film. Additional testing methods to observe the unloading behavior of the film in respect to pressure and relative resistance could contribute to further observations not covered. The study, however, highlights the feasibility of using accessible, low-cost materials for TFPS fabrication, offering insights for future sensor optimization
- PostChallenges and Opportunities within Design for Additive Manufacturing(2024) Dasappa Ashoka, Vijaya Kumar; Sidnekoppa, Luqmaan; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Hryha, Eduard; Soundarapandiyan, Gowtham; Hryha, Eduard; Knuts, Sören; Andersson, PetterAdditive manufacturing (AM) is transforming the design and manufacturing industries by allowing production of complex geometrical components that enhances efficiency and performance. However, despite its significant potential, AM poses several challenges, particularly in achieving cost-effective mass production. This study focused on interviewing engineers within an aerospace product development organization to identify the challenges and opportunities related to AM powder bed development. The responses were analyzed, and the findings were visually represented using an (Design for additive manufacturing) DfAM AIM diagram. Additionally a benchmark was performed with the additional industrial partner that has experienced in this area. The results from the interviews highlighted several key challenges in the AM design process and within the organization design practice. Design for additive manufacturing is a specialist area closely related to specific AM process. The study also identifies knowledge gaps and lack of communication between people and parts of organization. Process simulation software is not a standardized platform within the company, and difficult to use which means that front loading in design is still hard to perform. A conclusion is that, the organization needs to undertake several strategic improvements such as bridging the knowledge gap and improve the communication. Implementing standardized design guidelines specific to AM will streamline the design process and reduce reliance on trial-and-error methods. Furthermore, by integrating advanced simulation tools early in the design phase support structures can be optimized, and material waste can be reduced, and manufacturing outcome can be more accurately predicted. This integration will not only improve efficiency but also reduce costs. Lastly, investing in research and development to refine post-processing techniques and explore alternative materials could further enhance the economic viability of AM.
- PostGraphene oxide based ion-sieving membranes for water purification(2024) Macialowicz, Michal; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Klement, Uta; Xia, ZhenyuanGraphene oxide (GO), a promising two-dimensional (2D) material, has attracted much attention in membrane filtration techniques such as selective ion filtration and contaminant removal in water treatment. However, its versatility is limited by the fact that GO-based membranes tend to swell when submerged in water. This swelling behaviour will lead to an expansion of the 2D interlayer space, resulting in their inability to block particles in subnano-scale. In this thesis, I studied the modification of GO membrane to fine-tune the 2D interlayer distance and tested the ion-selectivity behaviour of modified GO membrane in lithium ion extraction applications. The impact of functional groups on GO membrane was evaluated by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy measurements. This work will provide a simple strategy in the development of emerging filtering materials for water purification applications.
- PostMachinability of bainitic steelsPapadopoulos, Pavlos; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Malakizadi, Amir; Malakizadi , AmirRecently, Volvo Trucks has been exploring various methods to reduce the CO2 footprint of large automotive vehicles. This involves not only limiting the emissions produced during vehicle operation but also minimizing the ecological impact of their manufacturing processes. One promising approach is the adoption of new materials that enable more efficient and lightweight designs. Bainitic steels are a class of materials that could meet these requirements. They offer superior mechanical properties compared to traditionally used steels with a pearlitic-ferritic microstructure, allowing for the design and production of smaller and lighter components without compromising strength. However, their enhanced mechanical properties can present challenges during machining operations. Thus, the aim of this thesis is to explore the machinability of bainitic steels and compare it with that of the currently adopted pearlitic-ferritic steels. Both materials were characterized in detail, focusing on microstructure evaluation, examination of non-metallic inclusions, and hardness testing. Additionally, a series of face turning operations were performed on each material to obtain data regarding cutting insert wear development, the impact of tool wear on machining forces, the interaction between the workpiece material and the cutting tool, the protective layers formed on the tool surfaces, and the effects of different cutting conditions on machining forces and chip formation. Overall, it was found that tool wear is more aggressive when machining bainitic steels, and machining forces are also higher. The layer formed on the cutting inserts exhibits relatively small differences between the two materials. Furthermore, chip breakability is slightly better during the machining of bainitic steel.
- PostInvestigating the User Experience of Physical and Digital Interfaces in Automotive Design(2020) Morvaridi Farimani, Hossein; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; I.C. MariAnne, Karlsson; Novakazi, FjollëAbstract With the continuous addition of new infotainment and driver assist features, In-Vehicle Infotainment systems (IVIs) are evolving to enhance convenience. However, balancing the system's output (information presentation) and input (vehicle controls) has become a major challenge for automotive companies. To address the complexity and information overload, many have shifted from physical controls to embedded digital touchscreens, raising questions about how far this transition should go. This shift from physical to digital interfaces presents both benefits and drawbacks. On one hand, digital touchscreens can increase driver distraction due to the visual load and eliminate haptic feedback and muscle memory. On the other hand, they offer flexibility and modern aesthetics. The primary research question was: What are the pros and cons of physical and digital interfaces from a user perspective? The secondary question focused on how the context of use (driving vs. non-driving) impacts user experience with each interface type. To explore these questions, this thesis investigated user satisfaction with both physical controls and digital touchscreens. Online user interviews and a literature review were conducted to assess the pros and cons of each interface in different contexts. The findings revealed that no single interface type is universally preferred. Users favored physical controls while driving, due to the haptic feedback and ease of use, but preferred digital interfaces in non-driving situations, due to their modern appeal and functionality. The study also revealed that user preferences varied based on behavior and attitudes, with early adopters perceiving digital interfaces as more trendy, while conservative users viewed physical interfaces as more reliable. These insights led to the development of design guidelines and a hybrid interface concept, blending physical and digital elements. The concept was evaluated and deemed a better solution than existing systems, though some refinements were suggested. The results provide a foundation for balancing physical and digital elements in future IVI designs. The design guidelines, developed from user needs and research findings, aimed to balance the strengths of physical and digital interfaces. These guidelines led to a conceptual UI design that combined physical controls for driving tasks with digital touchscreens for flexibility in non-driving contexts. The hybrid design was evaluated by both original participants and a wider audience, receiving positive feedback as an improvement over current systems. However, some aspects, like balancing ease of use with digital complexity, needed refinement. Overall, the guidelines, impact map, and evaluations represent progress toward more intuitive and user-friendly in-vehicle interfaces