A Finite Element Model for Static Performance Analysis of Gas Foil Bearings Based on Frictional Contacts

Abstract

In gas foil bearings, frictional contacts are one of the main factors that affect bearing performance, which is highly nonlinear. Using a finite element method, this article presents a nonlinear model for static performance analysis of foil bearings based on frictional contacts. The model incorporates the top foil and the interactions between bumps by modeling the foil structure with beam elements. The penalty method and the node-to-segment contact scheme are utilized to model the contacts of the structure. The stick–slip motions of the contact nodes are considered. Because the contact behavior is path dependent when the friction is taken into account, a step-by-step incremental iterative method is used for solution, in which the calculation at the present step is based on the results from the previous step. An algorithm is designed to determine the contact states, and the calculation at the next incremental step will not be performed until all contact states meet the check conditions in the present step. To couple the structure domain with the fluid film, each iterative step of the pressure calculation using the finite difference method is regard as an incremental step. This model is validated by comparisons with published results. Using this model, hysteretic behavior caused by friction and dissipative properties of the foil structure are analyzed under static condition.