Dynamic modelling and vibration transmission analysis of three-support flexible rotor system with active elastic support dry friction dampers

Flexible rotor is supported on multiple elastic supports to avoid large bending vibrations in critical speed regions. The vibration transmission characteristic of flexible rotor with elastic support is important in the dynamic response of entire rotor system. In this paper, the nonlinear dynamic response and vibration transmission characteristic of three support flexible rotor (TSFR) with active elastic support dry friction dampers (AESDFDs) is studied. Firstly, the dynamic FEM model of TSFR is derived and friction contact model of the AESDFD is built based on trajectory tracking method (TTM). The vibration transmission dynamic model is established by simplifying rolling bearing, elastic support and pedestal as a multi-degree-of-freedom (DOF) system. Then the steady state unbalance response of the AESDFDs-TSFR under acceleration and constant speed conditions were obtained and supporting system dynamic responses were analyzed by using numerical methods. In order to verify the dynamic characteristic of entire system, experimental test rig for the AESDFDs-TSFR was set up. The influence of normal force on the unbalance response curves and resonance peak values of disks and supporting system at the critical speed regions were compared and discussed. It is shown that the unbalance response of the AESDFDs-TSFR could be suppressed effectively by the AESDFDs. The simulated transmitted force of supporting system is suppressed by using AESDFD, the pedestal acceleration signals are reduced too. Then the experimental measured pedestal acceleration signals are reduced at same tendency. The vibration transmission through rolling bearing and elastic support to the pedestal is analyzed by orbit diagram, time waveform and frequency spectrum. The results could provide theoretical guide for vibration transmission analysis of flexible rotor and its supporting system.