A Statistical Characterization of the Effects of Mistuning in Multistage Bladed Disks

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Kiran X. D’Souza ◽  
Bogdan I. Epureanu
Keyword(s):  
Reduced Order Modeling ◽  
Single Stage ◽  
Bladed Disks ◽  
Statistical Characterization ◽  
Reduced Order ◽  
Design Component ◽  
Bladed Disk ◽  
Modeling Approach ◽  
Bladed Disk Assembly

A great deal of research has been conducted on the effects of small random variations in structural properties, known as mistuning, in single stage bladed disks. Due to the inherent randomness of mistuning and the large dimensionality of the models of industrial bladed disks, a reduced order modeling approach is required to understand the effects of mistuning on a particular bladed disk design. Component mode mistuning (CMM) is an efficient compact reduced order modeling method that was developed to handle this challenge in single stage bladed disks. In general, there are multiple stages in bladed disk assemblies, and it has been demonstrated that for certain frequency ranges accurate modeling of the entire bladed disk assembly is required because multistage modes exist. In this work, a statistical characterization of structural mistuning in multistage bladed disks is carried out. The results were obtained using CMM combined with a multistage modeling approach previously developed. In addition to the statistical characterization, a new efficient classification method is detailed for characterizing the properties of a mode. Also, the effects of structural mistuning on the characterization of the mode is explored.

A Statistical Characterization of the Effects of Mistuning in Multi-Stage Bladed Disks

2011 ◽  
Author(s):  
Kiran X. D’Souza ◽  
Bogdan I. Epureanu
Keyword(s):  
Reduced Order Modeling ◽  
Single Stage ◽  
Bladed Disks ◽  
Statistical Characterization ◽  
Reduced Order ◽  
Design Component ◽  
Bladed Disk ◽  
Modeling Approach ◽  
Multi Stage

A great deal of research has been conducted on the effects of small random variations in structural properties, known as mistuning, in single stage bladed disks. Due to the inherent randomness of mistuning and the large dimensionality of the models of industrial bladed disks, a reduced order modeling approach is required to understand the effects of mistuning on a particular bladed disk design. Component mode mistuning (CMM) is an efficient compact reduced order modeling method that was developed to handle this challenge in single stage bladed disks. In general, there are multiple stages in bladed disk assemblies, and it has been demonstrated that for certain frequency ranges accurate modeling of the entire bladed disk assembly is required because multi-stage modes exist. In this work, a statistical characterization of structural mistuning in multi-stage bladed disks is carried out. The results were obtained using CMM combined with a multi-stage modeling approach previously developed. In addition to the statistical characterization, a new efficient classification method is detailed for characterizing the properties of a mode. Also, the effects of structural mistuning on the characterization of the mode is explored.

A Reduced Order Model for Nonlinear Dynamics of Mistuned Bladed Disks With Shroud Friction Contacts

2018 ◽  
Author(s):  
S. Mehrdad Pourkiaee ◽  
Stefano Zucca
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Analysis ◽  
Forced Response ◽  
Reduced Order Model ◽  
Reduced Model ◽  
Order Model ◽  
Bladed Disks ◽  
Statistical Characterization ◽  
Reduced Order ◽  
Bladed Disk

A new reduced order modeling technique for nonlinear vibration analysis of mistuned bladed disks with shrouds is presented. It has been shown in the literature that the loss of cyclic symmetry properties which is known as mistuning could considerably increase the response level, localize the vibration around few number of blades and finally bring high cyclic fatigue. The developed reduction technique employs two component mode synthesis methods, namely, the Craig-Bampton (CB) method followed by a modal synthesis based on loaded interface modeshapes (Benfield and Hruda). In the new formulation the fundamental sector is divided into blade and disk components. The CB method is applied to the blade, where nodes lying on shroud contact surfaces and blade-disk interfaces are retained as master nodes, while modal reductions is performed on the disk sector with loaded interfaces. The use of loaded interface component modes allows removing the blade-disk interface nodes from the set of master nodes retained in the reduced model. The result is a much more reduced order model with no need to apply any secondary reduction. In the paper it is shown that the reduced order model of the mistuned bladed disk can be obtained with only single-sector calculation, so that the full finite element model of the entire bladed disk is not necessary. Furthermore, with the described approach it is possible to introduce the blade frequency mistuning directly into the reduced model. In this way, reduction is performed only once in case of multiple analyses, necessary for statistical characterization of the nonlinear response of the system. The nonlinear forced response is computed using the harmonic balance method (HBM) and alternating frequency/time domain (AFT) approach. Friction contacts are introduced into the FE model using a 3D contact element. Numerical simulations revealed the accuracy, efficiency and reliability of the new developed technique for nonlinear vibration analysis of mistuned bladed disks with shroud friction contacts.

scholarly journals A nonintrusive adaptive reduced order modeling approach for a molten salt reactor system

2020 ◽  
Vol 141 ◽  
pp. 107321 ◽  
Author(s):  
Fahad Alsayyari ◽  
Marco Tiberga ◽  
Zoltán Perkó ◽  
Danny Lathouwers ◽  
Jan Leen Kloosterman
Keyword(s):  
Molten Salt ◽  
Reduced Order Modeling ◽  
Reactor System ◽  
Molten Salt Reactor ◽  
Reduced Order ◽  
Modeling Approach

scholarly journals A Reduced Order Modeling Technique for Mistuned Bladed Disks

1997 ◽  
Vol 119 (3) ◽  
pp. 439-447 ◽  
Author(s):  
M. P. Castanier ◽  
G. O´ttarsson ◽  
C. Pierre
Keyword(s):  
Monte Carlo ◽  
Degrees Of Freedom ◽  
Order Reduction ◽  
Reduced Order Modeling ◽  
Modeling Technique ◽  
Mode Analysis ◽  
Bladed Disks ◽  
Engineering Structures ◽  
Element Analysis ◽  
Reduced Order

The analysis of the response statistics of mistuned turbomachinery rotors requires an expensive Monte Carlo simulation approach. Simple lumped parameter models capture basic localization effects but do not represent well actual engineering structures without a difficult parameter identification. Current component mode analysis techniques generally require a minimum number of degrees of freedom which is too large for running Monte Carlo simulations at a reasonable cost. In the present work, an order reduction method is introduced which is capable of generating reasonably accurate, very low order models of tuned or mistuned bladed disks. This technique is based on component modes of vibration found from a finite element analysis of a single disk-blade sector. It is shown that the phenomenon of mode localization is well captured by the reduced order modeling technique.

scholarly journals A goal-oriented reduced-order modeling approach for nonlinear systems

2016 ◽  
Vol 71 (11) ◽  
pp. 2155-2169 ◽  
Author(s):  
Jeff Borggaard ◽  
Zhu Wang ◽  
Lizette Zietsman
Keyword(s):  
Nonlinear Systems ◽  
Reduced Order Modeling ◽  
Reduced Order ◽  
Modeling Approach

Modeling the Microslip in the Flange Joint and Its Effect on the Dynamics of a Multistage Bladed Disk Assembly

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
Christian M. Firrone ◽  
Giuseppe Battiato ◽  
Bogdan I. Epureanu
Keyword(s):  
Element Model ◽  
Forced Response ◽  
Flange Joint ◽  
Reduced Order ◽  
Bladed Disk ◽  
Simple Geometry ◽  
Bladed Disk Assembly ◽  
Joint Contact ◽  
Turbine Disks ◽  
Complex Architecture

The complex architecture of aircraft engines requires demanding computational efforts when the dynamic coupling of their components has to be predicted. For this reason, numerically efficient reduced-order models (ROM) have been developed with the aim of performing modal analyses and forced response computations on complex multistage assemblies being computationally fast. In this paper, the flange joint connecting two turbine disks of a multistage assembly is studied as a source of nonlinearities due to friction damping occurring at the joint contact interface. An analytic contact model is proposed to calculate the local microslip based on the different deformations that the two flanges in contact take during vibration. The model is first introduced using a simple geometry representing two flanges in contact, and then, it is applied to a reduced finite element model in order to calculate the nonlinear forced response.

Sign in / Sign up

Export Citation Format

Share Document