Stability analysis of tilting pad journal bearings with flexible bases under sinusoidal loads

The tilting-pad journal bearing (TPJB) is widely used in gas turbine rotor systems due to its high load capacity and stability. However, high temperatures can cause significant thermal deformation of the bearing base, which will reduce the reliability of TPJBs. This study develops a novel transient lubrication model for TPJBs with a flexible base and applies an improved stability criterion. Stability under sinusoidal loads is compared between rigid and flexible bases, and stability boundaries under varying parameters are determined. The results show that the flexible base significantly reduces the stability of TPJBs, while increasing the length–diameter ratio and preload coefficient raises the critical load amplitude. The study provides theoretical guidance for TPJB design and selection.