Nonlinear vibration characteristics of rotor-bearing system with disc-shaft insufficient interference and flexible coupling misalignment fault

Abstract

Abstract For the traditional rotor system, the looseness fault caused by disc-shaft insufficient interference is always ignored. Aimed at the disc-shaft looseness caused by insufficient interference, a novel dynamic model of rotor-bearing system in the presence of coupling misalignment is established in this paper to make an investigation on the fault characteristics of disc-shaft looseness fault. Due to the nonlinearity of contact model between disc-shaft, the iterative solving of kinetic equations can be obtained by the combination of Newmark-β and Newton-Raphson methods. The vibration characteristics of the rotor-bearing system with and without the disc-shaft looseness caused by insufficient interference are compared and analyzed. The comparison results show that the slight collision between disc-shaft can be caused in the disc-shaft early looseness fault, and the beat vibration of system is appeared when the disc-shaft looseness become severe. Considering the effect of coupling misalignment, the vibration responses of system under different coupling misalignment are further discussed and parallel misalignment is proved to have a significant effect on the disc-shaft looseness. It is expected that the research results provide a useful reference for the identification and diagnosis of the looseness fault caused by disc-shaft insufficient interference.