Coupled bending and torsional vibrations of geared rotor system

CHE Yong-qiang1， XU Jing-xia2， QIAN Xiao-dong2， LI Wei1，SHENG De-ren1， CHEN Hui3
（1. Department of Energy Engineering， Zhejiang University， Hangzhou 310027， China；
2. Hangzhou Chinen Steam Turbine Power Co.， Ltd. ， Hangzhou 310018，China；
3. Shandong Electric Power Engineerig Consulting Institute Co.，Ltd.， Jinan 250000， China）

Abstract： In order to analyze vibration of geared rotor system，according to Finite element method and Lagrange method，gyroscopic effect and oil bearing was taken into consideration，a coupled lateral and torsional vibration model of rotor-bearing system was presented for analyze geared rotor vibration. The variation of mesh stiffness and mesh damping was taken into consideration，and the coupled lateral and torsional vibration model of gear pair system was established. Then，according to gear pair practical arrangement，the coordinate of rotor model and gear pair model was coupled and united by defining azimuth angle. A rotor-gear model which was closer to practice was obtained，and the critical speeds and models were calculated. The result shows that the critical speed of geared rotor is lower than single rotor's，and gear drive has obvious influence on rotor vibration.
Key words： gear drive；coupled bending and torsional vibrations；mesh stiffness；mesh damping