Identification of Distributed Dynamic Characteristics of Journal Bearing with Large Aspect Ratio under Shaft Bending

The classical theory of centralized dynamic characteristics with eight coefficients is adopted for traditional journal bearings. However, under cantilevered load, distributed along the axial direction will be generated bearing a large aspect ratio (L/D). A double-section loading method simulating shaft bending and excitation was developed, characteristic test-rig large-aspect-ratio set-up, novel four-time vertical eight-time cross were put forward, equations 16 deduced. test carried out. results showed that had small response amplitude in horizontal direction, vulnerable to interference by vibration test-rig. higher SNR more accurate identification results. When load not applied, evenly stiffness fluctuated slightly as rotation rate increased, while main damping decreased significantly. Shaft resulted significant increase local coefficients, which relative greater than coefficients. Increasing rotational speed can weaken effect bending, key factors cause axially nonuniform distribution are low load.