In order to diagnose effectively the blade-casing rubbing fault, it is very much necessary to simulate the casing vibration correctively and study the casing signals' characteristics under blade-casing rubbing. In this paper, the casing vibrations in aero-engine resulting from the blade-casing rubbing are simulated. Firstly, an improved aero-engine blade-casing rubbing model is introduced, in which, the effects of the number of blades and changes in the rotor-stator clearance on rubbing forces are considered, the improved rubbing model can simulate rubbing faults for various rubbing conditions, including single-point, multi-point, local-part, and complete-cycle rubbing on the casing and rotor. Secondly, the rubbing model was applied to the rotor-support-casing coupling model, and the casing acceleration responses under rubbing faults are obtained using the time integration approach, which combines the Newmark-beta method and an improved Newmark-beta method that is a new explicit integral method named the Zhai method. Thirdly, an aero-engine rotor tester with the casings was used to carry out rubbing experiments for single-point rubbing on the casing and complete-cycle rubbing on the rotor, the simulation result was found to agree well with the experimental values, and the improved blade-casing rubbing model was fully verified. Finally, other rubbing faults were simulated for various rubbing conditions and their rubbing characteristics were analyzed. (C) 2015 Elsevier Ltd. All rights reserved.
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