Characteristic analysis of gas foil bearing by using directing stiffness and damping model

This paper presents a directing stiffness and damping model of foil structure of gas foil bearings (GFBs) based on Castigliano’s theorem and virtual work theory. This theoretical model coupled with the Reynolds equation is solved by the finite difference method (FDM) to calculate the static and dynamic characteristics. The validity of the theoretical model of GFBs is verified by comparison with the experimental results. Several studies are conducted to visualize the performance of GFBs by examining the dynamic stiffness and damping coefficients in relation to rotational speeds, loads, structural parameters of foils, film clearances, and preloads. The results show that the influence of rotation speed and load on the rotor has an opposite trend. Structural parameters of foils have little effect on bearing performance under a low load. The improvement of bearing performance should mainly come from the radial and axial clearances of the gas film. The preload of foils is also a way to improve the stability.