Dynamic Analysis Of Geared Rotor System Using Modal Synthesis Method

The study of dynamic behavior of geared rotor system was done by modal synthesis method in this dissertation. The main contributions and conclusions of the thesis were summarized as follows:Firstly, the models of gear tooth deformation and meshing stiffness were built by equivalent tooth profile method, and the results were compared with FEM. Then the modeling of rotor system using FEM, derivation of the equations of motion, solution of its critical speed and unbalance response were sutdied. Based on the study, the modeling of geared rotor system and the application of modal synthesis method for rotor system were discussed.Secondly, the critical speeds and corresponding modes of some geared rotor system were analyzed with the method proposed. The results indicated that, the critical speeds of the rotor system supported on elastic bearing were smaller than those on rigid bearing, and the critical speeds of geared rotor system included the ones that their value were near to single rotor and some new derived ones. Some new coupling modes were produced except single rotor modes and coupling modes being similar to single rotor.Finally, unbalance response of some geared rotor system was studied. The influence of bearing conditions, coupling and unbalance distribution of rotor system was analyzed. Numerical result showed that the node amplitude of unbalance response of the rotor system supported on elastic bearing was larger than that on rigid bearing. In some conditions, unbalance response of system would decrease or increase because of the coupling. The speed of rotor was higher, the vibration response was larger. In order to improve the dynamic quality of the whole system, the dynamic balance precision of the high speed rotor should be improved.Dynamic behavior of geared rotor system was analyzed using modal synthesis method,...