Basic study on topological optimization of support structure in foil bearings

Abstract

Gas foil bearings are one of air bearings with a flexible bearing surface that can support the shaft in a stable condition. As a result, they have a higher damping performance than other air bearings. Since bearing characteristics is deeply dependent on the support structure, various support structures have been proposed. However, due to the complexity of the support structure, analytical evaluation is difficult. Therefore, empirical design is often used and the development speed is slow. In this study, a design method for foil bearings is proposed utilizing topological optimization which does not rely on the designer's experience. Characteristic analysis of the foil bearing with optimized support structure shows that increasing the flexibility of the leading edge results in a uniform film thickness at the trailing edge and increases the load capacity. Furthermore, by fixing the support structure at the rear, it was found that the load capacity could be maintained even when a large fluid force was applied.