A comparison between the friction and piezoelectric synchronized switch dampers for blisks

2018 ◽  
Vol 29 (12) ◽  
pp. 2693-2705 ◽  
Author(s):  
Jiuzhou Liu ◽  
Lin Li ◽  
Yu Fan
Keyword(s):  
Piezoelectric Materials ◽  
Vibration Reduction ◽  
Harmonic Balance Method ◽  
Single Mode ◽  
Excitation Level ◽  
State Response ◽  
Lumped Parameter ◽  
Engine Order ◽  
Lumped Parameter Models ◽  
Promising Solution

In this work, we explore the feasibility of applying the synchronized switch damping on negative capacitor damper to integrally bladed disks (blisks) by comparing its damping performance with that of the friction ring with the same added mass. Both dampers are coupled to the disk of the blisk. Namely, the friction ring is in contact with the underside of the wheel and the piezoelectric materials for synchronized switch damping on negative capacitor are bonded on the disk as well. The lumped parameter models are used for the blisk and dampers, and the multi-harmonic balance method is employed to obtain the steady-state response under engine-order excitations. The vibration-reduction performance of the dampers are compared with respect to the excitation level, the engine order, and multi-mode. This leads to a discussion concerning the parameter design for the synchronized switch damping on negative capacitor damper to achieve a comparable single-mode damping as the friction ring. We show that the synchronized switch damping on negative capacitor damper has a better performance for multiple modes and at a wider range of excitation level. These results indicate that the synchronized switch damping on negative capacitor damping can be a promising solution for the vibration reduction of blisks where the spatial and spectral distributions of the excitation are rich.

scholarly journals Friction Damper Optimisation: Simulation of Rainbow Tests

1999 ◽  
Author(s):  
Kenan Y. Sanliturk ◽  
David J. Ewins ◽  
Robert Elliott ◽  
Jeff S. Green
Keyword(s):  
Harmonic Balance Method ◽  
Lumped Parameter Model ◽  
Friction Damper ◽  
Blade Vibration ◽  
Friction Dampers ◽  
Lumped Parameter ◽  
Engine Order ◽  
Resonance Response ◽  
Theoretical Predictions ◽  
Different Characteristics

Friction dampers have been used to reduce turbine blade vibration levels for a considerable period of time. However, optimal design of these dampers has been quite difficult due both to a lack of adequate theoretical predictions and to difficulties in conducting reliable experiments. One of the difficulties of damper weight optimisation via the experimental route has been the inevitable effects of mistuning. Also, conducting separate experiments for different damper weights involves excessive cost. Therefore, current practice in the turbomachinery industry has been to conduct so-called ‘rainbow tests’ where friction dampers with different weights are placed between blades with a predefined configuration. However, it has been observed that some rainbow test results have been difficult to interpret and have been inconclusive for determining the optimum damper weight for a given bladed-disc assembly. A new method of analysis — a combination of Harmonic Balance Method and structural modification approaches — is presented in this paper for the analysis of structures with friction interfaces and the method is applied to search for qualitative answers about the so-called ‘rainbow tests’ in turbomachinery applications. A simple lumped-parameter model of a bladed-disc model was used and different damper weights were modelled using friction elements with different characteristics. Resonance response levels were obtained for bladed discs with various numbers of blades under various engine-order excitations. It was found that rainbow tests, where friction dampers with different weights are used on the same bladed-disc assembly, can be used to find the optimum damper weight if the mode of vibration concerned has weak blade-to-blade coupling (the case where the disc is almost rigid and blades vibrate almost independently from each other). Otherwise, it is very difficult to draw any reliable conclusion from such expensive experiments.

Modeling and Analysis of Friction Rim Dampers for Blisks

2005 ◽  
Author(s):  
Denis Laxalde ◽  
Jean-Jacques Sinou ◽  
Fabrice Thouverez ◽  
Jean-Pierre Lombard
Keyword(s):  
Steady State ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Design Guidelines ◽  
Lumped Parameter Model ◽  
Dynamical Analysis ◽  
Steady State Response ◽  
Modeling And Analysis ◽  
State Response ◽  
Lumped Parameter

A damping strategy for blisks of turbomachinery involving a friction rim is investigated. These rims, located in grooves underside the wheel of the blisks, are held in by centrifugal loads and the energy is dissipated when relative motions between the rim and the disk occur. A method of dynamical analysis of a cyclic blisk nonlinearly coupled with a split rim is presented: the steady-state response being calculated using an multi-harmonic balance method. Numerical simulations on a lumped-parameter model are presented for several damper characteristics and several excitation configurations. From these results, the performance of this damping strategy is discussed and some design guidelines are given. Finally the influence of mistuning on the damping performances is analysed.

scholarly journals Nonlinear vibration of knitted spacer fabric under harmonic excitation

2020 ◽  
Vol 15 ◽  
pp. 155892502098356
Author(s):  
Fuxing Chen ◽  
Hong Hu
Keyword(s):  
Nonlinear Vibration ◽  
Harmonic Balance Method ◽  
Harmonic Excitation ◽  
Polyurethane Foams ◽  
Excitation Level ◽  
Harmonic Amplitude ◽  
Damping Force ◽  
Spacer Fabric ◽  
Fabric System ◽  
Quadratic Stiffness

Knitted spacer fabrics can be an alternative material to typical rubber sponges and polyurethane foams for the protection of the human body from vibration exposure, such as automotive seat cushions and anti-vibration gloves. To provide a theoretical basis for the understanding of the nonlinear vibration behavior of the mass-spacer fabric system under harmonic excitation, experimental, analytical and numerical methods are used. Different from a linear mass-spring-damper vibration model, this study builds a phenomenological model with the asymmetric elastic force and the fractional derivative damping force to describe the periodic solution of the mass-spacer fabric system under harmonic excitation. Mathematical expression of the harmonic amplitude versus frequency response curve (FRC) is obtained using the harmonic balance method (HBM) to solve the equation of motion of the system. Parameter values in the model are estimated by performing curve fit between the modeled FRC and the experimental data of acceleration transmissibility. Theoretical analysis concerning the influence of varying excitation level on the FRCs is carried out, showing that nonlinear softening resonance turns into nonlinear hardening resonance with the increase of excitation level, due to the quadratic stiffness term and the cubic stiffness term in the model, respectively. The quadratic stiffness term also results in biased vibration response and causes an even order harmonic distortion. Besides, the increase of excitation level also results in elevated peak transmissibility at resonance.

Dynamics of the Gear Train Set in Wind Turbine

2011 ◽  
Vol 697-698 ◽  
pp. 701-705
Author(s):  
D.D. Ji ◽  
Y.M. Song ◽  
J. Zhang
Keyword(s):  
Wind Turbine ◽  
Dynamic Model ◽  
Harmonic Balance Method ◽  
Planetary Gear ◽  
Gear Train ◽  
Dynamic Responses ◽  
Multi Stage ◽  
Lumped Parameter ◽  
Cartesian Coordinate ◽  
The Impact

A lumped-parameter dynamic model for gear train set in wind turbine is proposed to investigate the dynamics of the speed-increasing gear box. The proposed model is developed in a universal Cartesian coordinate, which includes transversal and torsional deflections of each component, time-varying mesh stiffness, gear profile errors and external excitations. By solving the dynamic model, a modal analysis is performed. The results indicate that the modal properties of the multi-stage gear train in wind turbine are similar to those of a single-stage planetary gear set. A harmonic balance method (HBM) is used to obtain the dynamic responses of the gearing system. The responses give insight into the impact of excitations on the vibrations.

Lumped parameter models for two-ventricle and healthy and failing extracardiac Fontan circulations

2021 ◽  
Author(s):  
Matthew G Doyle ◽  
Marina Chugunova ◽  
S Lucy Roche ◽  
James P Keener
Keyword(s):  
Single Ventricle ◽  
Left Ventricular ◽  
Sensitivity Analyses ◽  
Surgical Strategies ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Fontan Failure ◽  
Existence Of Periodic Solutions ◽  
Mathematical Definitions ◽  
Extracardiac Fontan

Abstract Fontan circulations are surgical strategies to treat infants born with single ventricle physiology. Clinical and mathematical definitions of Fontan failure are lacking, and understanding is needed of parameters indicative of declining physiologies. Our objective is to develop lumped parameter models of two-ventricle and single-ventricle circulations. These models, their mathematical formulations and a proof of existence of periodic solutions are presented. Sensitivity analyses are performed to identify key parameters. Systemic venous and systolic left ventricular compliances and systemic capillary and pulmonary venous resistances are identified as key parameters. Our models serve as a framework to study the differences between two-ventricle and single-ventricle physiologies and healthy and failing Fontan circulations.

scholarly journals Vibration Analysis of a Nonlinear System With Cyclic Symmetry

2010 ◽  
Vol 133 (2) ◽  
Author(s):  
Aurélien Grolet ◽  
Fabrice Thouverez
Keyword(s):  
Nonlinear Differential Equations ◽  
Geometrical Nonlinearity ◽  
Harmonic Balance Method ◽  
Dynamic Responses ◽  
Cyclic Symmetry ◽  
Force Amplitude ◽  
Closed Curves ◽  
Nonlinear Modes ◽  
Nonlinear Localization ◽  
Engine Order

This work is devoted to the study of nonlinear dynamics of structures with cyclic symmetry under geometrical nonlinearity using the harmonic balance method (HBM). In order to study the influence of the nonlinearity due to large deflection of blades, a simplified model has been developed. It leads to nonlinear differential equations of the second order, linearly coupled, in which the nonlinearity appears by cubic terms. Periodic solutions in both free and forced cases are sought by the HBM coupled with an arc length continuation and stability analysis. In this study, specific attention has been paid to the evaluation of nonlinear modes and to the influence of excitation on dynamic responses. Indeed, several cases of excitation have been analyzed: punctual one and tuned or detuned low engine order. This paper shows that for a localized, or sufficiently detuned, excitation, several solutions can coexist, some of them being represented by closed curves in the frequency-amplitude domain. Those different kinds of solution meet up when increasing the force amplitude, leading to forced nonlinear localization. As the closed curves are not tied with the basic nonlinear solution, they are easily missed. They were calculated using a sequential continuation with the force amplitude as a parameter.

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