Modeling & Analysis of Bladed Disk with Cracks and Mistuning

Download or read book Modeling & Analysis of Bladed Disk with Cracks and Mistuning written by Tianyi Hu and published by . This book was released on 2018 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, efficient techniques are presented for analyzing the dynamics of mistuned bladed disks with cracks. The analysis of the influence of cracks coupled with the influence of mistuning on the dynamics of bladed disks is computationally challenging for several reasons: (i) complex geometry of modern turbines results in very high dimensional computational models; (ii) mistuning in these structures breaks the cyclic symmetry in these systems; and (iii) cracks further disrupt the symmetry property and introduce a piecewise-linear nonlinearity into these systems. Recently several approaches have been developed to handle these challenges individually. The component mode mistuning (CMM) approach was developed to efficiently model small mistuning in bladed disks. The X-Xr method was developed for generating reduced-order models of cyclically symmetric systems with cracks. More recently, the generalized bilinear amplitude approximation (BAA) technique was created to efficiently approximate the nonlinear vibrational response of a class of piecewise-linear nonlinear systems. This work modifies and combines these techniques, for the first time, to enable modeling and analysis of mistuned bladed disks with cracks in an efficient manner. The novel method can generate the reduced-order model of full disks using single-sector models only and approximate the nonlinear vibrational response of mistuned disks with significantly reduced computational effort. A mistuned bladed disk with a crack is parametrically studied using the proposed approach. The influence of different mistuning patterns and crack lengths on the dynamics of the system is discussed.