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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2022, Vol. 43 ›› Issue (9): 625442.doi: 10.7527/S1000-6893.2021.25442

• Special Topic: Operation Safety of Aero-engine • Previous Articles     Next Articles

Vibration characteristics of rotating cracked-blade-flexible-disk coupling system

WU Zhiyuan1, YAN Han1, WU Linchao1, MA Hui2, QU Yegao1, ZHANG Wenming1   

  1. 1. State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China;
    2. School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
  • Received:2021-03-03 Revised:2021-04-07 Online:2022-09-15 Published:2021-06-29
  • Supported by:
    National Science and Technology Major Project (2017-V-0009);National Natural Science Foundation of China (11972112)

Abstract: Being exposed to severe environments with complex excitation for a long time, aero-engine blades can easily cause damage and cracks, which will change the modal characteristics of the blade-disk coupling system and deviate from the initial design state. Taking the rotating cracked-blade-flexible-disk coupling system as the research object, a dynamic model is established, in which the flexible disk and rotating blades are investigated based on Kirchhoff plate and Timoshenko beam theories; the blade crack is equivalent to the rotational stiffness based on the released strain energy and Castigliano's theorem. The proposed method is verified by modal test and finite element method. In addition, the effects of crack length, crack position, disk thickness and rotating speed on the inherent characteristics of the coupling system are investigated. The research results show that: the crack leads to the destruction of the initial orthogonal blade-disk coupling modal and the phenomenon of modal localization, and the corresponding frequencies decrease with the increase of the crack length; the closer the crack position is to the blade tip, the modes localization disappears, and two-order orthogonal modes are formed; with the increase of the disk thickness, the frequency veering phenomenon occurs, and the blade-bending mode is related to multi-order modes of the disk; with the increase of speed, the frequency veering phenomenon occurs, and the blade-bending mode is related to the rest blade-bending modes at the high rotational speed.

Key words: rotating cracked blade, flexible disk, modal test, finite element method, frequency veering, modal localization

CLC Number: