Reduced Order Models and Coupling Characteristics of the Mistuned Blade-Disk-Shaft Integration Rotor.

Background: The disc-blade-shaft integration rotor is a new type of structural component used to improve the performance of aeroengine. It usually suffer from severe vibration problems due to the low stiffness and low damping capacity. Therefore, the dynamic behavior is an important issue to be researched in the design process. Purpose: The main purpose of this work is to investigate the coupling vibration characteristics of multi-component and the influence of blade mistuning on the vibration localization of the integrated rotor. Methods: To solve the large-scale calculation problem in dynamic analysis, the improved prestress hybrid interface component mode synthesis method is adopted to obtain reduced-order model of the complex rotor. By combining with nodal diameter spectrum (NDS) method, the natural characteristics and the forced vibration response of the integration rotor system are analyzed. Then, deterministic mistuning mode is introduced into the reduction model and vibration localization characteristics is investigated. Results: Compared with the full finite element model, the error of frequency calculation with the reduced-order model of the integration rotor is relatively small. After considering prestress effects, the frequency of the integration rotor increases. The vibration response of the integrated rotor changes obviously when the parameters such as excitation order, coupling stiffness changed. Conclusion: The results of frequency and mode shapes verified the validity of the improved prestress hybrid interface component mode synthesis method. For the integration rotor, the multi-stage and multi-component coupled mode appears mainly with low nodal diameters, with the increase of ND number, the mode coupling degree among the dominated vibration stage blisk and other stage blisk decreases. Besides, the mistuning pattern, the excitation order and the inter-stage coupling stiffness have great influence on the vibration localization of the rotor system. [ABSTRACT FROM AUTHOR]