Vibration Control for Integrally Bladed Disks Using Friction Ring Dampers

Author(s):  
Denis Laxalde ◽  
Fabrice Thouverez ◽  
Jean-Pierre Lombard

A damping strategy for integrally bladed disks (blisks) is discussed in this paper; this involves the use of friction rings located underside the wheel of bladed disks. The forced response of the blisk with friction rings is derived in the frequency domain using a frequency domain approach known as Dynamic Lagrangian Frequency-Time method. The blisk is modeled using a reduced-order model and the rings are modeled using beam elements. The results of some numerical simulations and parametric studies are presented. The range of application of this damping device is discussed. Parametric studies are presented and allow to understand the dissipation phenomena. Finally some design and optimization guidelines are given.

Author(s):  
Javier Avalos ◽  
Marc P. Mignolet

The focus of this paper is on demonstrating the potential to damp entire bladed disks using dampers on only a fraction of the blades. This problem is first considered without the presence of random mistuning, and it is demonstrated that a few dampers at optimized locations can lead to a significant reduction in the forced response of the entire bladed disk. Unfortunately, this optimum design may not be robust with respect to random mistuning and a notable fraction of the reduction in forced response obtained may disappear because of mistuning. To regain the reduction in forced response but with mistuning present, robustness to mistuning is enhanced by using intentional mistuning in addition to dampers. The intentional mistuning strategy selected here is the A/B pattern mistuning in which the blades all belong to either type A or B. An optimization effort is then performed to obtain the best combination of A/B pattern and damper location to minimize the mistuned forced response of the disk. The addition of intentional mistuning in the system is shown to be very efficient, and the optimum bladed disk design does indeed exhibit a significant reduction in mistuned forced response as compared with the tuned system. These findings were obtained on both single-degree-of-freedom per blade-disk models and a reduced order model of a blisk.


Author(s):  
Javier Avalos ◽  
Marc P. Mignolet

The focus of this paper is on demonstrating the potential to damp entire bladed disks using dampers on only a fraction of the blades. This problem is first considered without the presence of random mistuning and it is demonstrated that a few dampers at optimized locations can lead to a significant reduction in the forced response of the entire bladed disk. Unfortunately, this optimum design may not be robust with respect to random mistuning and a notable fraction of the reduction in forced response obtained may disappear because of mistuning. To regain the reduction in forced response but with mistuning present, robustness to mistuning is enhanced by using intentional mistuning in addition to dampers. The intentional mistuning strategy selected here is the A/B pattern mistuning in which the blades all belong to either type A or B. An optimization effort is then performed to obtain the best combination of A/B pattern and damper location to minimize the mistuned forced response of the disk. The addition of intentional mistuning in the system is shown to be very efficient and the optimum bladed disk design does indeed exhibit a significant reduction of mistuned forced response as compared to the tuned system. These findings were obtained on both single-degree-of-freedom per blade disk models and a reduced order model of a blisk.


Author(s):  
S. Mehrdad Pourkiaee ◽  
Stefano Zucca

A new reduced order modeling technique for nonlinear vibration analysis of mistuned bladed disks with shrouds is presented. 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 (LI) 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 are performed on the disk sector with LIs. The use of LI 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 (ROM) with no need to apply any secondary reduction. In the paper, it is shown that the ROM 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. The nonlinear forced response is computed using the harmonic balance method and alternating frequency/time domain approach. 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.


Author(s):  
S. Mehrdad Pourkiaee ◽  
Stefano Zucca

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.


2013 ◽  
Vol 136 (7) ◽  
Author(s):  
Yasharth Bhartiya ◽  
Alok Sinha

The results from a reduced order model based on frequency mistuning are compared with those from recently developed modified modal domain analysis (MMDA). For the academic bladed rotor considered in this paper, the frequency mistuning analysis is unable to capture the effects of geometric mistuning, whereas MMDA provides accurate estimates of natural frequencies, mode shapes, and forced response.


Author(s):  
Ilaria Palomba ◽  
Dario Richiedei ◽  
Alberto Trevisani

Resonant system design and optimization is usually supported by finite element models. Large dimensional models are often needed to achieve the desired accuracy in the representation of the vibrational behaviour at the frequency of interest. Unfortunately, large dimensional models are frequently too cumbersome to be actually useful, mainly at the optimization stage. On the other hand, the choice of the most appropriate reduction strategy and dimension for a reduced-order model is generally left to designers’ experience. Having recognized the effectiveness and spreading of the Craig Bampton reduction technique, the aim of this paper is to propose a rigorous ranking method, called Interior Mode Ranking (IMR), for the selection of the interior normal modes of the full order model to be inherited by the reduced order one. The method is aimed at finding the set of interior modes of minimum dimensions which allows achieving a desired level of accuracy of the reduced order model at a frequency of interest. The method is here applied to a resonator widely employed in industry: an ultrasonic welding bar horn, which is usually designed to operate excited in resonance. The results achieved through the application of the IMR method are compared with those yielded by other ranking techniques available in literature in order to prove its effectiveness.


AIAA Journal ◽  
2009 ◽  
Vol 47 (5) ◽  
pp. 1277-1287 ◽  
Author(s):  
John A. Judge ◽  
Christophe Pierre ◽  
Steven L. Ceccio

2004 ◽  
Vol 126 (1) ◽  
pp. 159-165 ◽  
Author(s):  
D. M. Feiner ◽  
J. H. Griffin

This paper is the second in a two-part study of identifying mistuning in bladed disks. It presents experimental validation of a new method of mistuning identification based on measurements of the vibratory response of the system as a whole. As a system-based method, this approach is particularly suited to integrally bladed rotors, whose blades cannot be removed for individual measurements. The method is based on a recently developed reduced-order model of mistuning called the fundamental mistuning model (FMM) and is applicable to isolated families of modes. Two versions of FMM system identification are applied to the experimental data: a basic version that requires some prior knowledge of the system’s properties, and a somewhat more complex version that determines the mistuning completely from experimental data.


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