Cracking-Induced Mistuning in Bladed Disks PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Cracking-Induced Mistuning in Bladed Disks PDF full book. Access full book title Cracking-Induced Mistuning in Bladed Disks by . Download full books in PDF and EPUB format.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 13
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 13
Get Book Here
Book Description
Author: Tianyi Hu
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 43
Get Book Here
Book Description
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.
Author: Vsevolod Kharyton
Publisher:
ISBN:
Category :
Languages : en
Pages : 206
Get Book Here
Book Description
The general aim of the study is to offer mathematical model of the process, which can allow crack identification in the compressor or turbine blade of aircraft gas-turbine engine in operation. Within the frameworks of this goal cracked blade non-linear dynamic model was elaborated and introduced to the global model of the bladed disk. Crack induced non-linearity was taken into account applying contact analysis elements in conjunction with harmonic balance method. For system size reduction the sub-structuring methodology using fixed-interface method was applied. It supposes the crack location to be considered as interface between two dependent, in this case, substructures. Such approach was applied to the both uncoupled cracked blade and bladed disk models. Also considering uncoupled cracked blade the centrifugal forces effect was examined. It was concluded, that depending on crack properties (location and size), it will be enough to use the linear crack presence formulation supposing crack to be always open (initial gap). During simulation of the bladed disk forced response containing cracked blade the effect of blade mistuning was simulated. Simulation results shown that at certain level of mistuning it becomes impossible to separate cracked blade response. Furthermore such crack detectability decreases with absence of cracked blade frequency localization. The last one phenomenon is very important diagnostic sign, which simplifies cracked blade detection at almost all cases. The last phase of the work was devoted to simulation of blade tip-timing method application for cracked blade identification. It consisted in blade arriving time generation, blade tip amplitudes reconstruction and bladed disk frequency response calculation on the base of measured (simulated) time data. Such approach allowed us to identify cracked blade in the same way as in frequency response analysis. Generally speaking, blade tip-timing method can be used as the part of engine health monitoring system for compressor or turbine blades dynamic performances monitoring.
Author: American Institute of Aeronautics and Astronautics
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 960
Get Book Here
Book Description
Author: Elhamosadat Alavifoumani
Publisher:
ISBN:
Category : University of Ottawa theses
Languages : en
Pages :
Get Book Here
Book Description
Crack initiation and propagation in the bladed disks of aero-engines caused by high-cycle fatigue under cyclic loads could result in the breakdown of the engines if not detected at an early stage. Although a number of fault detection methods have been reported in the literature, it still remains very challenging to develop a reliable online technique to accurately diagnose defects in bladed disks. One of the main challenges is to characterize signals contaminated by noises. These noises caused by very dynamic engine operation environment. This work presents a new technique for engine bladed disk crack detection, which utilizes advanced analysis of clearance and time-of-arrival signals acquired from blade tip sensors. This technique involves two stages of signal processing: 1) signal pre-processing for noise elimination from predetermined causes; and 2) signal post-processing for characterizing crack initiation and location. Experimental results from the spin rig test were used to validate technique predictions.
Author: Jan Ronnie Bladh
Publisher:
ISBN:
Category :
Languages : en
Pages : 596
Get Book Here
Book Description
Author: Gísli Sigurbjörn Óttarsson
Publisher:
ISBN:
Category :
Languages : en
Pages : 442
Get Book Here
Book Description
Author: Jia Li
Publisher:
ISBN:
Category :
Languages : en
Pages : 398
Get Book Here
Book Description
Author: Sang-Ho Lim
Publisher:
ISBN:
Category :
Languages : en
Pages : 482
Get Book Here
Book Description
Author: John A. Judge
Publisher:
ISBN:
Category :
Languages : en
Pages : 576
Get Book Here
Book Description
