Model Localization Of Bladed-Disk System

Periodic structures in the astronautic and aeronautical engineering, building structures and large rotating machine, and other engineering fields have been widely used. For example, a satellite antenna structure, high-rise architecture framework, and turbine blade-disc structure are typical cycle structures. Bladed-disc system is circular symmetric structure. The design and study of dynamic characteristics of aviation turbine engine, fault diagnosis, and improvement of its reliability are of great significance.Mistuning of bladed-disk assemblies is caused by small differences of the geometrical shape and/or material property among the blades. Such small differences are inevitable in practice even though people always try to reduce them in the manufacturing process. Theoretical investigation and practical measurements show that there exists vibration localization in the mistuning bladed-disk assemblies, and the blades may be damaged and destroyed in serious cases. In large-scale bladed-disk assemblies, the bracing that plays a very important role in the enhancement of stability of the structure is often simplified as a linear spring without mass, and the effect of the bracing mass on the dynamical responses and vibration localization of the system is neglected.The primary objective of the present study is to investigate the mechanism of vibration localization caused by mistuning and find an effective way to eliminate the vibration localization by properly choosing the mass and stiffness of the bracing. The coupled bladed-disk structure is described in terms of a coupled pendulum system. In such a way, the simplicity of the model makes it possible to understand the characteristics of the vibration localization involved in the system. The maximum forced vibration amplitudes of the blades are examined around their natural frequencies using MATLAB. The combined effects of mistuning, stiffness coupling, damping, and the bracing mass on vibration localization of bladed-disk assemblies are also investigated. The analytical approach proposed here may be used as a valuable guideline for safe and reliable designs of bladed-disk assemblies.