Modelling a Friction Damper: Analysis of the Experimental Data and Comparison With Numerical Results

2006 ◽  
Author(s):  
Christian M. Firrone ◽  
Daniele Botto ◽  
Muzio M. Gola
Keyword(s):  
Experimental Data ◽  
Dry Friction ◽  
Negative Impact ◽  
Real Life ◽  
Forced Response ◽  
Nonlinear Frequency ◽  
Friction Damper ◽  
Typical Application ◽  
Static Test ◽  
Underplatform Damper

High cycle fatigue is one of the main causes of failure of blades in turbomachinery. The negative impact of HCF on turbomachinery blades can be reduced by dry friction vibration damping. A typical application of dry friction damping in gas turbine is the so called “underplatform damper”. In this work a ‘real life’ asymmetric underplatform damper is experimentally tested with two real blades. A static test rig is used to obtain the nonlinear frequency response function of a mock-up made with two real blades with an underplatform damper between them. This paper addresses an underplatform damper model taking into account damper rotation. The proper mathematical formulations have been developed and forced response calculation of the system have been performed. Comparison with experimental data are carried out for different values of excitation forces and for pre-load similar to real centrifugal force values.

Fatigue Damage Prevention on Turbine Blades: Study of Underplatform Damper Shape

2007 ◽  
Vol 347 ◽  
pp. 159-164 ◽  
Author(s):  
Teresa Berruti ◽  
Christian M. Firrone ◽  
M. Pizzolante ◽  
Muzio M. Gola
Keyword(s):  
Turbine Blades ◽  
Forced Vibrations ◽  
Forced Response ◽  
Numerical Code ◽  
Vibration Energy ◽  
Test Rig ◽  
Blade Vibration ◽  
Static Test ◽  
Underplatform Damper ◽  
Contact Parameters

Forced vibrations can lead to an irreparable damage of a blade array. Devices called “underplatform damper” that dissipate the vibration energy are employed in order to reduce blade vibration amplitude. The present paper deals with the design of the underplatform damper. A numerical code to calculate the forced response of a blade array with dampers has been previously purposely developed. A method is here proposed for the estimation of the unknown contact parameters demanded by the code. The computation results are here validated by means of comparison with experimental results on a static test rig. Three dampers with different shape are tested.

Forced Response of Shrouded Bladed Disc Assemblies: A Jointed Experimental Numerical Approach

2004 ◽  
Author(s):  
F. D’Ambrosio ◽  
E. Chatelet ◽  
J. Ravoux ◽  
G. Jacquet-Richardet
Keyword(s):  
Dynamic Behavior ◽  
Dry Friction ◽  
Flexible Structures ◽  
Numerical Approach ◽  
Forced Response ◽  
Friction Damper ◽  
Element Analysis ◽  
First Results ◽  
Numerical Finite Element ◽  
Set Up

The objective of the proposed study is to progress towards a better modeling of bladed assemblies dynamic. Coupling devices are introduced in bladed stages to increase frequencies of resonance above the range of possible excitations. Commonly they are not only used to stiffen flexible structures but also to increase damping by dry friction, reducing the amplitude of vibration. Consequently, the resulting dynamic behavior is complex and highly non linear. In order to improve numerical capabilities used for the design of part span shrouds and to gain a better understanding of the dynamic behavior of shrouded assemblies, a jointed experimental and numerical approach has been conducted. A first experimental test based on a cantilever beam is considered. The beam, excited by a controlled electrodynamic shaker, is associated to a dry friction damper at its free end. A numerical finite element analysis and a macroslip model of contact has been developed. The solution method in time domain allows accurate computations of response levels and gives the main harmonics of the steady state response. Comparison between numerical and experimental results is very good. A second experimental set up is constituted by an assembly of 13 beams, cyclically mounted around a common disk and linked by geometrically simplified shrouds. The set up allows controlling the resultant forces in the contact and is able to exhibit all states of contact from fully slipping to fully stuck. The first results obtained are associated to a single couple of blades brought into contact.

Blades Forced Response Analysis With Friction Dampers

1998 ◽  
Vol 120 (2) ◽  
pp. 468-474 ◽  
Author(s):  
M. Berthillier ◽  
C. Dupont ◽  
R. Mondal ◽  
J. J. Barrau
Keyword(s):  
Time Domain ◽  
Dry Friction ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Forced Response ◽  
Response Analysis ◽  
Friction Damper ◽  
Friction Dampers ◽  
Fan Blade

A multiharmonic frequency domain analysis combined with a Craig-Bampton component mode synthesis is presented to compute the dry friction damped forced response of blades. The accuracy of the analysis is established, for a cantilever beam with a dry friction damper attached, by comparison with experimental results and time domain analysis. The method has then been applied to a model fan blade damped by a blade to ground damper.

scholarly journals Application of Artificial Intelligence (AI) for Sustainable Highway and Road System

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 60
Author(s):  
Md Arifuzzaman ◽  
Muhammad Aniq Gul ◽  
Kaffayatullah Khan ◽  
S. M. Zakir Hossain
Keyword(s):  
Experimental Data ◽  
High Performance ◽  
Adhesion Force ◽  
Model Development ◽  
Real Life ◽  
Bayesian Optimization ◽  
Support Vector ◽  
Adhesive Properties ◽  
Bayesian Optimization Algorithm ◽  
The Mean

There are several environmental factors such as temperature differential, moisture, oxidation, etc. that affect the extended life of the modified asphalt influencing its desired adhesive properties. Knowledge of the properties of asphalt adhesives can help to provide a more resilient and durable asphalt surface. In this study, a hybrid of Bayesian optimization algorithm and support vector regression approach is recommended to predict the adhesion force of asphalt. The effects of three important variables viz., conditions (fresh, wet and aged), binder types (base, 4% SB, 5% SB, 4% SBS and 5% SBS), and Carbon Nano Tube doses (0.5%, 1.0% and 1.5%) on adhesive force are taken into consideration. Real-life experimental data (405 specimens) are considered for model development. Using atomic force microscopy, the adhesive strength of nanoscales of test specimens is determined according to functional groups on the asphalt. It is found that the model predictions overlap with the experimental data with a high R2 of 90.5% and relative deviation are scattered around zero line. Besides, the mean, median and standard deviations of experimental and the predicted values are very close. In addition, the mean absolute Error, root mean square error and fractional bias values were found to be low, indicating the high performance of the developed model.

scholarly journals Improved Reliability of Bladed Disks due to Friction Dampers

1997 ◽  
Author(s):  
Walter Sextro ◽  
Karl Popp ◽  
Ivo Wolter
Keyword(s):  
Dry Friction ◽  
Three Dimensional ◽  
Line Contact ◽  
Two Dimensional ◽  
Centrifugal Forces ◽  
Friction Damper ◽  
Blade Vibration ◽  
Friction Dampers ◽  
Bladed Disk ◽  
Bladed Disk Assembly

Friction dampers are installed underneath the blade platforms to improve the reliability. Because of centrifugal forces the dampers are pressed onto the platforms. Due to dry friction and the relative motion between blades and dampers, energy is dissipated, which results in a reduction of blade vibration amplitudes. The geometry of the contact is in many cases like a Hertzian line contact. A three-dimensional motion of the blades results in a two-dimensional motion of one contact line of the friction dampers in the contact plane. An experiment with one friction damper between two blades is used to verify the two-dimensional contact model including microslip. By optimizing the friction dampers masses, the best damping effects are obtained. Finally, different methods are shown to calculate the envelope of a three-dimensional response of a detuned bladed disk assembly (V84.3-4th-stage turbine blade) with friction dampers.

Research on Damping Vibration Reduction Design Method of Aeroengine Supporting Structure System

2020 ◽  
Author(s):  
Chao Li ◽  
Binglong Lei ◽  
Yanhong Ma ◽  
Jie Hong
Keyword(s):  
Dry Friction ◽  
Dynamic Stiffness ◽  
Vibration Reduction ◽  
Vibration Response ◽  
Contact Friction ◽  
Friction Damper ◽  
Support Structure ◽  
Response Control ◽  
Structure System ◽  
Supporting Structure

Abstract Typical turbofan engine-support-structure systems having a high thrust-to-weight ratio are light, and the structure primarily comprises a plate and shells. The local vibration response of the support structure is excessively large when different frequency loads are applied. A structural vibration response control method based on dry friction damping is proposed to control the excessive vibration response. A dry friction damper with dynamic suction was designed to enhance the damping characteristics of the rotor supporting structure system in the wide frequency domain, without sacrificing the dynamic stiffness of the structure. The system is designed to effectively control the vibration response of the supporting structure at the working-speed frequency. Through theoretical modeling and simulation analyses, the influence of friction contact and damper structure characteristics on the damping effect is described quantitatively. Furthermore, the design idea and the damping process of the supporting structure are described. The calculation results show that the contact friction of the dry friction damper can consume the vibration energy of the supporting frame. A reasonable design of the contact characteristics and geometric configuration parameters of the damper can further optimize the vibration-reduction effect, and thereby improve the vibration response control design of the supporting structure system of aeroengines.

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