The aim of this thesis is to develop alternative designs for structural support elements used within cryostats. These support elements need to perform as thermal isolators or with minimum thermal conductance, since they are connected between two flanges at different temperatures. Also, they need to have good mechanical performance to provide adequate structural stability to the cryostat. The existing supports were analysed for their mechanical and thermal design, manufacturing time and costs, which served as a reference point, against which the new alternative designs were compared to. In all, three designs were developed with iterative CAD principles and keeping Design for Manufacturing as the central focus. Static heat load arising due to the new supports was calculated for each design respectively. To understand the structural characteristics of the new support designs, FEA was done on all the designs under loads that resembled operational conditions occurring in the cryostat. After the designs were found viable from FEA results, they were prototyped with relevant fabrication methods and suppliers. These designs were then tested for their mechanical performance by conducting inhouse bending and tensile load tests. Their thermal performance was also tested by installing them in cryostats and cooling until 4K. Qualitative feedback and analysis was also done during the testing phase.
The findings were presented as a comparison amongst four support designs-one existing and three new. The factors that were prioritized in this comparison were- mechanical performance in bending and tensile loading tests, heat load from thermal tests, manufacturing process complexity and cost. It was found that relatively cheaper supports can be manufactured when DFM is applied in early design stage, which is in accordance with the literature review. Some of the proposed designs show significantly lower heat loads than the standard support but are weaker in the mechanical aspect. In all, it is a matter of which characteristic to prioritize the most and then select a design accordingly. The proposed designs showed promising results and are a good starting point for the case company to delve deeper into. The limitations mainly involved stress singularities arising in FEA and reliability of mechanical test setup. Vibration testing and extending modularity aspect to other cooling stages and cryostat models are future endeavours of this project.
