To improve the foil bearing performance

a novel foil journal bearing with top foil thickness variation in axial direction was proposed. A wide groove extending in circumferential direction

within micron magnitude

was manufactured in the mid-plane zone of top foil. To consider the top foil thickness variation

the 2D thick plate finite element model was employed to simulate the top foil deformation. Based on Newton-Raphson iterative method and finite difference method

the coupled pressure equation and foil deflection equation were solved

and the gas pressure distribution and load capacity of the novel foil bearing were obtained. The dynamic characteristics were solved using perturbation method and the influence of the wide groove depth on bearing performance was investigated theoretically. The results indicate that the novel foil bearing with top foil thickness variation axially can decrease the gas edge leakage and improve hydrodynamic pressure effectively

so the load capacity and dynamic characteristics are improved. Moreover

with the increment of the wide groove depth on top foil

the load capacity and direct stiffness are enhanced further. For the foil journal bearing with a wide groove depth of 8 μm

the load capacity and direct stiffness increase by about 11.8% and 12.1% respectively

compared with the traditional foil journal bearing.