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.
WU Zhiyuan
,
YAN Han
,
WU Linchao
,
MA Hui
,
QU Yegao
,
ZHANG Wenming
. Vibration characteristics of rotating cracked-blade-flexible-disk coupling system[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2022
, 43(9)
: 625442
-625442
.
DOI: 10.7527/S1000-6893.2021.25442
[1] LIU M R, ZHU J, LIANG E B, et al. Vibration measurement on compressor rotor blades of aero-engine based on tip-timing[J]. Journal of Aerospace Power, 2019, 34(9): 1895-1904 (in Chinese). 刘美茹, 朱靖, 梁恩波, 等. 基于叶尖定时的航空发动机压气机叶片振动测量[J]. 航空动力学报, 2019, 34(9): 1895-1904.
[2] LIU M R, TENG G R, XIAO X, et al. Vibration measurement of turbine rotor blades of aero-engine based on blade tip-timing[J]. Journal of Aerospace Power, 2020, 35(9): 1954-1963 (in Chinese). 刘美茹, 滕光蓉, 肖潇, 等. 基于叶尖定时的航空发动机涡轮叶片振动测量[J]. 航空动力学报, 2020, 35(9): 1954-1963.
[3] ZENG J, CHEN K K, MA H, et al. Vibration response analysis of a cracked rotating compressor blade during run-up process[J]. Mechanical Systems and Signal Processing, 2019, 118: 568-583.
[4] XU H L. Research on key technology of crack detection in rotating blades by non-contact on-line blade tip-timing method[D]. Changsha: National University of Defense Technology, 2018: 1-18 (in Chinese). 徐海龙. 旋转叶片裂纹的叶端定时非接触在线检测关键技术研究[D]. 长沙: 国防科技大学, 2018: 1-18.
[5] LESAFFRE N, SINOU J J, THOUVEREZ F. Stability analysis of rotating beams rubbing on an elastic circular structure[J]. Journal of Sound and Vibration, 2007, 299(4-5): 1005-1032.
[6] CARASSALE L, MAURICI M, TRAVERSONE L. Reduced-order modeling of compressor blades by 1D finite elements[C]//Proceedings of ASME Turbo Expo 2015: Turbine Technical Conference and Exposition, 2015.
[7] SUN Q, MA H, ZHU Y P, et al. Comparison of rubbing induced vibration responses using varying-thickness-twisted shell and solid-element blade models[J]. Mechanical Systems and Signal Processing, 2018, 108: 1-20.
[8] LIU C, JIANG D X. Crack modeling of rotating blades with cracked hexahedral finite element method[J]. Mechanical Systems and Signal Processing, 2014, 46(2): 406-423.
[9] XIE J S, ZI Y Y, ZHANG M Q, et al. A novel vibration modeling method for a rotating blade with breathing cracks[J]. Science China Technological Sciences, 2019, 62(2): 333-348.
[10] BEHZAD M, GHADAMI A, MAGHSOODI A, et al. Vibration based algorithm for crack detection in cantilever beam containing two different types of cracks[J]. Journal of Sound and Vibration, 2013, 332(24): 6312-6320.
[11] DADO M H F, ABUZEID O. Coupled transverse and axial vibratory behaviour of cracked beam with end mass and rotary inertia[J]. Journal of Sound and Vibration, 2003, 261(4): 675-696.
[12] ZHAO C G, ZENG J, MA H, et al. Dynamic analysis of cracked rotating blade using cracked beam element[J]. Results in Physics, 2020, 19: 103360.
[13] YANG L H, YANG Z S, MAO Z, et al. Dynamic characteristic analysis of rotating blade with transverse crack—part Ⅰ: Modeling, modification, and validation[J]. Journal of Vibration and Acoustics, 2021, 143(5): 051010.
[14] HUANG B W, KUANG J H. Variation in the stability of a rotating blade disk with a local crack defect[J]. Journal of Sound and Vibration, 2006, 294(3): 486-502.
[15] KUANG J H, HUANG B W. The effect of blade crack on mode localization in rotating bladed disks[J]. Journal of Sound and Vibration, 1999, 227(1): 85-103.
[16] HUANG B W. Effect of number of blades and distribution of cracks on vibration localization in a cracked pre-twisted blade system[J]. International Journal of Mechanical Sciences, 2006, 48(1): 1-10.
[17] FANG X, TANG J, JORDAN E, et al. Crack induced vibration localization in simplified bladed-disk structures[J]. Journal of Sound and Vibration, 2006, 291(1-2): 395-418.
[18] SHE H X, LI C F, TANG Q S, et al. Veering and merging analysis of nonlinear resonance frequencies of an assembly bladed disk system[J]. Journal of Sound and Vibration, 2021, 493: 115818.
[19] CHIU Y J, HUANG S C. The influence of a cracked blade on rotor's free vibration[J]. Journal of Vibration and Acoustics, 2008, 130(5): 054502.
[20] YUAN H Q. Rotor dynamics fundamentals[M]. Beijing: Metallurgical Industry Press, 2013: 227-235 (in Chinese). 袁惠群. 转子动力学基础[M]. 北京: 冶金工业出版社, 2013: 227-235.
[21] MA H, LU Y, WU Z Y, et al. A new dynamic model of rotor-blade systems[J]. Journal of Sound and Vibration, 2015, 357: 168-194.
[22] OKABE A, KUDO T, SHIOHATA K, et al. Reduced modeling for turbine rotor-blade coupled bending vibration analysis[J]. Journal of Engineering for Gas Turbines and Power, 2012, 134(2): 022502.
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