Nonlinear dynamic mechanical response analysis of dual-segment single-span rotor-bearing system under normal condition and misalignment fault

As a highly widespread and practical construction, it is vital to investigate rotor bearing system’s structure, components, and faults in order to enhance functioning performance. The dual-segment single-span rotor bearing system is explored experimentally in this work. Case studies of systems with cylindrical lubricated bearings and elliptical lubricated bearings are investigated under normal operating conditions and angular misalignment faults. Through comparative analysis, the findings demonstrate that a misalignment defect increases the displacement of a dual-segment single-span rotor bearing system by 1.2–1.6 times when compared to the normal operating state. According to the instability factor distribution, the stability of system with elliptical lubricated bearings is 130–190% higher than that of cylindrical lubricated bearings. On the contrary, the system with cylinder lubricated bearings performs worse under normal operating conditions than the two examples under misalignment conditions. Furthermore, for the case of an angular misalignment fault, 2X, 3X, and 4X frequency component excitations produce relatively larger system disturbances in 1500–2500 rpm rotating speed region, 1000–2000 rpm rotating speed region, and 1000–1500 rpm rotating speed region of the system, respectively.