Dynamic Analysis and Safety Design for Aero-Engine Rotor-Support System Under the Blade-off

Considering turbine blade-off event in the typical turboshaft engine, dynamic model of the rotor-support system is established, and the modal characteristic, as well as vibration response under the turbine blade-off are investigated with centered finite difference method. Impact load is detected at the moment of blade loss due to the sudden unbalance, and the vibration response goes to extreme when the rotor decelerates though the critical speeds. The bearing loads on each support are investigated and the response on the rear supports is much high than the front supports, possible leads to bearing failure and structure damage. Structural safety designs are proposed, including the sealing brake structure and the metal-rubber ring, to ensure the integrity of the bearings and the support structure. The validity of these applications is quantitatively analyzed. It is demonstrated that the vibration amplitude and the bearing loads are both significantly reduced during the rotor deceleration when applied with the safety designs. Some other conclusions instructive for further engineering applications are also obtained.