Abstract: Rod fastening rotor is usually used in heavy duty gas turbine rotor-support system, of which critical speed calculation differs from that of the integral rotor. In the framework of Riccati transfer matrix method, discretization of central tie-rod fastening rotor structure with detailed analysis was conducted. Taking into account the impacts which are brought by bearing support and meshing face tooth on dynamic characteristics of rotor system, a computation model of rotor-support system was further established. In this way, critical speeds and the corresponding modes were obtained.The calculated result shows a good agreement with the test measurement result, which implies that the method is accurate and computation model  is reliable. This approach can also be applied to analyze dynamic characteristics of rotors with homogenous structure.  

Key words: dynamical modeling, critical speed, central tie-rod fastening rotor, transfer matrix