Nonlinear Dynamic Characteristics Of Diaphragm Coupling-rotor System With Misalignment

Diaphragm coupling is a kind of high performance flexible coupling, which is widely used in many domains such as aviation, ships, oil chemical industry. It can not only play a good role in the transmission of torque and power, but also can effectively compensate for the relative displacement. So, it plays the role of shock absorption and protection for the rotor system. Misalignment of the diaphragm coupling is one of the common problems of the rotor system. The study of the dynamic characteristics of the system provides a certain basis for the safe operation and fault diagnosis of the rotor system.According to the motion characteristics of diaphragm coupling system with parallel misalignment and angular misalignment, the dynamic models of the two cases are established, and the dynamic equations of the system are obtained by using the Lagrange equation in these two cases. The average method is used to solve the dynamic equations of the diaphragm coupling with parallel misalignment, and the bifurcation equations of the resonant of the system are acquired. Then numerical iterative method is used to obtain the resonance steady solution of the system. And then the results are compared with the numerical simulation results. The system responses with the variation of the dimensionless speed, misalignment, damping coefficient and mass eccentricity are observed in the cases of parallel misalignment and angular misalignment by using numerical simulation. And finally the dynamic characteristics are analyzed.The study shows that the nonlinear dynamic response of the diaphragm coupling system is complex and variable with the changing of the dimensionless speed. The system has the motions that periodic, double-periodic, quasi-periodic and chaotic. But always a larger speed range can be found when the system running stability. And this period is suitable for the system’s working. During the influence of the misalignment, damping coefficient and mass eccentricity on the system, a critical value exists, and below which the system running stability, but unstable when exceeding.