Dynamic characteristics of vibration localization of mistuned bladed disk due to shroud and blade damages

Abstract

Dynamic behaviors of turbine blades are important for the dynamic design of whole-bladed disk systems. The bladed disk systems with shrouds are used to achieve advanced functions in operation. The shrouds are used to connect several blades as a bladed packet, and several bladed packets are assembled as a bladed disk. Previous researches mainly focus on the mistuning of the bladed disk. However, in operation, the shrouds often suffer damage and wear, and it will lead to shrouds mistuning. The shroud is a critical component for adjusting the coupling strength of the blade to the blade. The innovation of this paper is to study the coupling dynamics problem caused by blade mistuning and shroud damage. The localized vibration of the bladed disk is caused by the blade mistuning, and the shroud damage can also cause the localized vibration of the bladed disk. The coupling dynamic behaviors of bladed disk caused by blade mistuning and shroud damage are important. Therefore, the dynamic behaviors of a mistuned bladed disk with the shroud are important for the bladed disk. A numerical method is conducted to investigate the dynamic characteristics of the whole bladed disk with shroud. The coupling effect between shroud and blade mistuning on the dynamic behaviors of the bladed disk is researched. The numerical model is validated by assuming the shroud and blade mistuning is zero. The coupling effect of shroud and blade mistuning leads to the characteristics being more complicated. Bladed packet is the basic part of the bladed disk with shroud. In order to study the modal characteristics of bladed packets due to shroud, an experiment is conducted. It is worth noting that the first sub remains invariable with the increasing of stiffness ratio.