Effects of shear stiffness in top foil structure on gas foil bearing performance based on thick plate theory

The effects of top foil shear stiffness for an incompressible journal foil bearing are discussed based on thick plate theory of top foil. The structural model includes bending, shear of thick plate and elastic foundation effects of bump foil. By employing the finite element method and the finite difference method, the compressible gas lubricated Reynolds equation and the film thickness equation are solved coupled together. The static characteristics such as film thickness and attitude angle are obtained and compared with literature results to verify the validation of the proposed method. Then the numerical results of thick plate model are compared with Kirchhoff plate model to study the shear stiffness effects in top foil structure on bearing performance. Results demonstrate that shear stiffness effects are significant in an elastically supported foil bearing and the shear effects should be considered in the estabilishment of 2D plate top foil model.