Design and manufacturing of Cantilever Gas Foil Bearings: Compliant Foil Analytical Stiffness Model, FEA and experimental validation
Cantilever Gas Foil Bearings provide a workaround in terms of manufacturing accuracy, due to high precision on the laser cutting of the beams on a flat foil. After the heat treatment, these beams will provide enough stiffness and damping to the bearing to operate under a wide range of conditions. Th...
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| Tipo de recurso: | tesis de maestría |
| Fecha de publicación: | 2024 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/422974 |
| Acceso en línea: | https://hdl.handle.net/2117/422974 |
| Access Level: | acceso abierto |
| Palabra clave: | Bearings (Machinery) Finite element method Coixinets (Maquinària) Elements finits, Mètode dels Àrees temàtiques de la UPC::Enginyeria electrònica |
| Sumario: | Cantilever Gas Foil Bearings provide a workaround in terms of manufacturing accuracy, due to high precision on the laser cutting of the beams on a flat foil. After the heat treatment, these beams will provide enough stiffness and damping to the bearing to operate under a wide range of conditions. The goal of this master thesis is to address the lack of available methods to design different cantilever compliant foils in addition to contributing to the heat treatment feasibility. To attain this goal, an analytical expression to determine the static stiffness of the compliant foil has been developed relying on beam theory formulations for a simply supported beam with some particularities. With the aim of verifying and finding weaknesses of the analytical model, a Finite Element Analysis has been carried out for both one section of the foil and the complete structure. Simulation results show that simulating one section is not representative of real conditions, nevertheless, a good agreement with the analytical model is found. After the appropriate determination of the geometrical parameters of the foil bearing in mind the presented requirements, a design has been suggested and manufactured. Stress relief annealing for the foil is required to achieve accurate dimensions and ensure contact of all cantilevers with the bearing sleeve while not interfering with the cantilevers’ shape. For this reason, a heat treatment tool has been designed and manufactured with excellent precision and alignment results. Prior to the manufacturing, a thermal stress simulation was carried out verifying no plastic deformation for all contact surfaces. For the purpose of verifying experimentally the analytical model and manufacturing process, a test rig has been designed and built. A series of static loading and unloading cycles at different directions of the foil have been performed obtaining displacement values for every load. With the intention of obtaining a stiffness value per unit area some assumptions on the contact area, load distribution and clearance determination have been made. In light of the results, a good congruence is found between the analytical model and simulations with the experimental results, especially on the loading area of interest, nevertheless, a certain error in the results is acknowledged to the assumptions made. For this reason, a new test rig and other cantilever compliant foil designs are suggested to circumvent reliance on the considered assumptions. |
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