Experimental and simulation-based investigation of oil film stiffness in thrust bearings

The thrust bearing is a critical component ensuring the axial stability of the crankshaft, yet its characteristics are often overlooked in most dynamic research. The oil film formed during its operation is often regarded as a spring structure with fixed stiffness, resulting in deviations between the analysis results and actual situations. In this study, a combination of simulation and experimentation was employed to investigate the oil film stiffness characteristics of the crankshaft thrust bearing based on its operating principle. Segmented equivalent oil film stiffness values were inversely identified from the load-dependent axial resonance characteristics of the test rig and correlated with the sensor-indicated thrust clearance under the present test configuration. Based on these experimentally identified results, an empirical stiffness-clearance relationship was established for engineering use.