Design and analysis of one-pad gas foil bearing with three-part gas film produced by adjusting the length of sliding beams

The one-pad sliding-beam gas foil bearing is studied in this paper. The size of the multiple sliding beams in the bearing is adjusted, which results in dividing the gas film pressure into three parts. The finite element mesh of the bottom foil is established based on rectangle and triangle elements, and the finite element model of sliding beams is established based on the plate element with five degrees of freedom. The separation and friction of the foils are considered, and the model of the foils is established based on minimum potential energy theorem and Newton–Raphson method. The mechanical model of the bearing is finally established by fluid-solid interaction. The calculation scheme is programmed by MATLAB, and the reliability of the model is verified by experiments. The numerical results show that with the increase of preload or the decrease of nominal clearance, the gas film pressure is divided into three parts gradually. Compared with the three-pad structure, the bearing in this paper has better bearing capacity. With nominal clearance being 30 µm, the maximum bearing capacity is obtained with a preload of 10 µm, and the maximum direct damping is obtained with a preload of 20 µm. A proper layout of sliding beams can improve the bearing capacity, but it could also weaken the dynamic performance. The variation of the initial bending stiffness distribution of sliding beams has little impact on the dynamic performance, but it can significantly affect the bearing capacity. When the stiffness of sliding beams of axial middle face is larger than that of the end face, the bearing capacity is obviously improved.