Large amplitude dynamic behavior of thrust air bearings: Modeling and experiments

Large dynamic loading of air thrust bearings may result in undesired contact between bearing surfaces. The counteracting nonlinear aerodynamic forces delivered by the thin air film in the bearing, which determine if contact will occur, may be computed either by solving the nonlinear Reynolds equation or by using a grid with position dependent dynamic bearing coefficients. It is shown by a numerical case study that both numerical approaches give similar response results. Moreover, it is demonstrated that the model based on the nonlinear Reynolds equation accurately predicts the experimental large amplitude dynamic behavior of an axial-symmetric air thrust bearing. Hence, both numerical approaches may be used to predict if bearing surfaces will make contact due to large impulsive external forces.