Dynamic Characteristic Analysis of a Rotor System With Pedestal Looseness Under Two Load Cases

By taking a single-span rotor system with two discs as the research object,the pedestal looseness fault was simulated using a piecewise linear spring/damping model and then this model was combined with the finite element(FE) model of the rotor system.Two different load conditions were determined based on API Standard 617 and the spectrum cascade and rotor orbit were used to analyze the influence of dynamic characteristics on shaft system by the stiffness of non-loose bolts,looseness clearance and rotating speed.The results show that different bifurcation forms,multiple periodic and quasi-periodic motions can be observed under two load cases,and the system motion is more complicated under the second load case.The results will provide theoretical references for fault diagnosis,dynamic design,and safe operation of rotor-bearing system.