Influence of diaphragm coupling on vibration characteristics

　　1. The influence of bending vibration
　　In the rotor system, bending vibration has a great influence on the normal operation of the unit.The second-order critical speeds obtained by independent calculation of span, third span, and fourth span are given, and the second-order critical speeds are the critical speeds of the entire rotor system.
　　Through the comparison of the critical speeds in the two tables, the critical speed of the rotor system coincides with the single-span critical speed, that is, the critical speed of the single-span rotor is the critical speed of a certain order of the entire rotor system.It shows that the diaphragm coupling can well absorb the bending vibration of the rotor system, and the elastic deformation of the diaphragm is used to compensate the displacement caused by the bending, which effectively reduces the influence of the bending vibration between the spans.
　　2. The effect of coupled bending and torsion vibration
　　Through the finite element method, the critical speed of the flexural-torsional coupled vibration of the rotor system is obtained.Moreover, after considering the bending and torsion coupling, the critical speed of the flexural vibration of each order of the rotor system has not changed much, but the obvious changes can be seen from the vibration mode of each order, indicating that the diaphragm coupling is relatively more elastic in torque transmission. Low, the cushioning and damping performance is worse than for bending vibration.