Design of a test system for dynamic load characteristics of radial foil air bearings

Abstract

To meet the performance-testing requirements of radial foil air bearings with different specifications, a test system enabling rapid shaft replacement was designed and constructed to address the structural complexity, difficulty in shaft replacement, and alignment errors caused by repeated assembly in existing experimental platforms. The system employs a shaftconnection structure combining tapered-surface fitting with bolt preloading, allowing test shafts with different journal diameters to be replaced efficiently while reducing assembly-induced errors. Modal analysis of the rotor system was performed using ANSYS Workbench. The results show that the first critical speed of the rotor system is higher than the designed operating speed, indicating that resonance can be effectively avoided. A Python-based measurement and control program was developed to implement rotational-speed control, multi-sensor data acquisition and system-level safety protection. Six repeated experiments were conducted on a commercially available radial foil air bearing to evaluate the start-up torque, shutdown torque and temperature rise. The coefficients of variation of the starting and stopping torques were 10.7% and 11.2%, respectively, while that of the temperature rise was 10.5%. These results demonstrate that the proposed test system exhibits good repeatability and operational stability.