Investigations on the Frictional Hysteresis Effect of Multi-Leaf Journal Foil Bearing: Modeling, Predictions and Validations

Multi-leaf journal foil bearing (MLJFB) is well known for its applications in the air cycle machines (ACMs) of airplanes. However, its frictional energy dissipation mechanism of overlapped foils has not been theoretically studied and is still not clear to researchers. This paper models the frictional sliding/sticking behaviors between adjacent foil leaves based on the tangent gap, applying the penalty method of contact mechanics. Large foil deformations are calculated to simulate the processes of foil assembly and rotor insertion using nonlinear curve beam elements. Predictions of the frictional hysteresis characteristics of MLJFB are obtained, influenced by foil boundary conditions, leaf number, bearing radial clearance and other foil structural parameters, which correlate well with the test results. This study lays solid theoretical foundations for the static and dynamic research of MLJFB.