Effect of Corrosion Pit on the Structural Characteristics of Foil Journal Bearings

Abstract Due to corrosive environment, material loss in a localized area leads to formation of a corrosion pit. It diminishes the structural integrity and performance of product. To predict and analyze the effect of corrosion pit on the performance of gas foil bearings (GFBs), FEM analysis of bump-type GFBs is carried out. The effect of corrosion pit is investigated for three different shapes: circular, square and triangular. In this study, the FEM analysis of bump-type GFBs is performed in ANSYS software. Firstly, the influence of a corrosion pit is analyzed for various shapes under different pressure loading. These results show that the presence of a corrosion pit developed high-stress crack intensity, which can result in crack initiation in foil bearings. As pressure loading increased, the stress crack intensity in foil bearings increased. Among different pit shapes, the circular pit shape induces the maximum stress crack intensity in foil bearings, which shows that the crack initiation in foil bearings is observed for a circular pit. Then, the influence of a corrosion pit on the structural stiffness of foil bearings is evaluated for various foil materials under different friction coefficients. These results show that the influence of friction coefficient in foil bearings is increased within the presence of a corrosion pit.