Cracked Blades Detuning Ye Panzhen Dynamic Coefficients

Bladed disk is a core component of turbomachinary. Theoretically speaking, it is a cyclically periodic structure. However, in practice, as a result of inevitable faults in materials, manufacturing tolerance and in-service damage, parameters of blades such as shape, stiffness and quality along the circumference are not absolutely identical, thus mistuning is caused. Mistuning may lead to vibration localization in bladed disks, which would result in the high cyclic fatigue failure, even causing a disastrous consequences.Aiming at practical problems in project, this paper researches the vibration characteristic analysis of bladed disks with cracked blades Firstly, the vibration characteristics of cracked blades is studied theoretically, theoretical analysis is correct,which has been verified by experiments,and provide basis for later research work.Secondly,according to the frequency bandpass characteristics of the bladed disk, the first put forward the concept of vibration frequency of localization, and find that mistuned bladed disk vibration localization and crack propagation can promote each other, which perfect the vibration characteristics of Mistuned bladed disk with single cracked blade. Thirdly, based on the analytical model for a bladed disk is formulated using lumped-mass beam, the effect of two cracked blades on vibration characteristic of bladed disks is investigated, comparing to vibration characteristic of bladed disk with single crack, the results demonstrate mistuned bladed disks with two cracked blades appears two localized vibration frequencies, modal information are more rich, vibration characteristics are More complicated, and discovers that two peculiar blades are extremely insensitive to changing of the crack depth. Finally, reveals the influence of distribution of cracked blades on response characteristics of mistuned bladed disk Numerical simulation indicates that distribution of the cracked blades can affect the fundamental frequency of mistuned bladed disk and level of modal localization ,and when two cracked blades are adjacent, the fundamental frequency of mistuned bladed disk is the minimum and level of modal localization is the maximum, and centrifugal force has abated effect to localization of vibration in mistuned bladed disks with cracked blades.The research conclusion, not only improving and developing the basic theory of the mistuned bladed disks vibration localization, also for providing the essential guidance required for blade disk fault diagnosis and damage identification.