Attenuation of Free Vibration Using Particle Impact Damper

2007 ◽  
Author(s):  
Hamid R. Hamidzadeh
Keyword(s):  
Free Vibration ◽  
Damping Ratio ◽  
Particle Impact ◽  
Constrained Layer Damping ◽  
Equivalent Viscous Damping ◽  
Impact Damper ◽  
Equivalent Damping ◽  
Vibrating System ◽  
Damping Characteristics ◽  
Moving Particle

The particle impact damper is an effective vibration damping treatment that can be used in the cases where visco-elastic constrained layer damping fails due to excessive surrounding temperature. In this type of passive damping, particles move in a container attached to the vibrating system resulting in plastic impact with the container. In the presented theoretical study, the damping characteristics of free oscillation for a vertical system with an initial displacement are considered and a governing equation for the system under free vibration with a particle damper is derived. To evaluate the damping characteristics for the free vibrating system, the equivalent damping ratio is determined by considering both kinematics and kinetics of the particle motion and its impacts with the container. The presented solution concludes that in general damping effectiveness can be enhanced by increasing the mass of the particle in comparison with total mass of the system. Mathematical optimum clearance for the moving particle and the equivalent viscous damping ratio are determined for the best performance of the particle impact damper.

scholarly journals Damping of Beam Vibrations Using Tuned Particles Impact Damper

2020 ◽  
Vol 10 (18) ◽  
pp. 6334 ◽  
Author(s):  
Mateusz Żurawski ◽  
Robert Zalewski
Keyword(s):  
Resonant Frequency ◽  
Granular Material ◽  
Cantilever Beam ◽  
Vibration Amplitude ◽  
Active Damping ◽  
Particle Impact ◽  
Impact Damper ◽  
Vibrating System ◽  
Damping Characteristics ◽  
Dynamical Features

The presented paper reveals an innovative device which is the Tuned Particle Impact Damper (TPID). The damper enables the user change the dynamical features of the vibrating system thanks to rapidly tuning the volume of the container where the grains are locked. The effectiveness of proposed semi-active damping methodology was confirmed in experiments on vibrations of a cantilever beam excited by kinematic rule. Various damping characteristics captured for different volumes of the grains container and mass of granular material are presented. It is confirmed that the proposed TPID device allowed for efficient attenuation of the beam’s vibration amplitude in the range of its resonant frequency vibrations.

Analysis of Beam-Like Structures With Displacement-Dependent Friction Forces: Part I — Single-Degree-of-Freedom Model

1995 ◽  
Author(s):  
Wayne E. Whiteman ◽  
Aldo A. Ferri
Keyword(s):  
Dry Friction ◽  
Damping Ratio ◽  
Strong Dependence ◽  
Time Integration ◽  
Single Mode ◽  
Stick Slip ◽  
Friction Forces ◽  
Equivalent Damping ◽  
Damping Characteristics ◽  
Parameter Values

Abstract The dynamic behavior of a beam-like structure undergoing transverse vibration and subjected to a displacement-dependent dry friction force is examined. In Part I, the beam is modeled by a single mode while Part II considers multi-mode representations. The displacement dependence in each case is caused by a ramp configuration that allows the normal force across the sliding interface to increase linearly with slip displacement. The system is studied first by using first-order harmonic balance and then by using a time integration method. The stick-slip behavior of the system is also studied. Even though the only source of damping is dry friction, the system is seen to exhibit “viscous-like” damping characteristics. A strong dependence of the equivalent natural frequency and damping ratio on the displacement amplitude is an interesting result. It is shown that for a given set of parameter values, an optimal ramp angle exists that maximizes the equivalent damping ratio. The appearance of two dynamic response solutions at certain system and forcing parameter values is also seen. Results suggest that the overall characteristics of mechanical systems may be improved by properly configuring frictional interfaces to allow normal forces to vary with displacement.

Free Vibration Test for Damping Characteristics of Hybrid Polyester Matrix Composite with Carbon Particles

2016 ◽  
Vol 11 ◽  
pp. 1-6
Author(s):  
K. Karthik ◽  
R. Rohith Renish ◽  
I. Irfan Ahmed ◽  
T. Niruban Projoth
Keyword(s):  
Free Vibration ◽  
Hybrid Composites ◽  
Glass Fibers ◽  
Damping Ratio ◽  
Mode Shapes ◽  
Vibration Test ◽  
Engineering Structures ◽  
Carbon Filler ◽  
Damping Characteristics ◽  
Free Vibration Test

In this research aims to study the damping characteristics of hybrid polymer composite, which can be used in engineering structures and in many other applications. Hybrid composites are namely Glass fiber and carbon filler reinforced with polyester and epoxy matrix have been prepared by vacuum bag molding fabrication technique. Then the free vibration test were conducted using FFT analyzer with Lab VIEW software. The damping ratio and natural frequency were investigated for fabricated composites. Then through ANSYS, the mode shapes and natural frequencies were determined and the results were compared with experimental results. The damping ratio increases with increased volume fractions of E-glass fibers for both the types of polymer composites. Vibrations are concerned to large structures such as aircraft, as well as small structures such as electronic equipments.

scholarly journals Prediction of the dynamic response of a plate treated by particle impact damper

2013 ◽  
Vol 228 (5) ◽  
pp. 799-814 ◽  
Author(s):  
Moez Trigui ◽  
Emmanuel Foltete ◽  
Noureddine Bouhaddi
Keyword(s):  
Dynamic Response ◽  
Excitation Frequency ◽  
Element Model ◽  
Nonlinear Damping ◽  
Design Parameters ◽  
Particle Impact ◽  
Equivalent Viscous Damping ◽  
Impact Damper ◽  
Experimental Characterisation ◽  
Good Agreement

In this paper, an experimental characterisation of a particle impact damper (PID) under periodic excitation is investigated. The developed method allows the measurement of damping properties of PID without the supplementary use of a primary structure. The passive damping of PID varies with the excitation frequency and its design parameters. The nonlinear damping of PID is then interpreted as an equivalent viscous damping to be introduced in a finite element model of a structure to predict its dynamic response. The results of numerical simulations are in good agreement with those of experiment and show the relevance of the developed method to predict the dynamic behaviour of a structure treated by PID’s.

Viscoelastic Damping of Ortho-Planar Springs

2008 ◽  
Author(s):  
Sterling Anderson ◽  
Brian D. Jensen
Keyword(s):  
Damping Ratio ◽  
Spring Constant ◽  
Viscoelastic Damping ◽  
Viscous Damping ◽  
Constrained Layer Damping ◽  
Equivalent Viscous Damping ◽  
Background Theory ◽  
Modal Damping ◽  
Damping Treatments ◽  
Equivalent Viscous Damping Ratio

This paper presents the design of a damped ortho-planar spring that uses viscoelastic constrained-layer damping to reduce the free response oscillations of the spring and suppress modal resonances in that response. Background, theory, and applications surrounding fully-compliant ortho-planar springs and viscoelastic damping treatments are first discussed. Next, the effect of various constrained layer thickness on the spring constant, damping ratio, equivalent viscous damping ratio, modal frequencies, and modal damping ratios are compared, and trends discussed. The results show that the equivalent viscous damping co-efficient of the viscoelastically-damped spring can be increased to nearly 2.5 times that of the reference configuration without significantly changing the size of the constraining layer or the spring constant of the ortho-planar spring. Viscoelastically-damped ortho-planar springs are also shown to successfully remove mechanical noise from a contact resistance test stand.

scholarly journals Free Vibration and Damping of Rotating Composite Shaft with a Constrained Layer Damping

2016 ◽  
Vol 2016 ◽  
pp. 1-20 ◽  
Author(s):  
Yongsheng Ren ◽  
Yuhuan Zhang
Keyword(s):  
Free Vibration ◽  
Equations Of Motion ◽  
Beam Theory ◽  
Constrained Layer Damping ◽  
Rotating Shaft ◽  
Rotating Speed ◽  
Damping Characteristics ◽  
Reinforced Composite ◽  
Composite Shaft ◽  
Passive Constrained Layer Damping

The free vibration and damping characteristics of rotating shaft with passive constrained layer damping (CLD) are studied. The shaft is made of fiber reinforced composite materials. A composite beam theory taking into account transverse shear deformation is employed to model the composite shaft and constraining layer. The equations of motion of composite rotating shaft with CLD are derived by using Hamilton’s principle. The general Galerkin method is applied to obtain the approximate solution of the rotating CLD composite shaft. Numerical results for the rotating CLD composite shaft with simply supported boundary condition are presented; the effects of thickness of constraining layer and viscoelastic damping layers, lamination angle, and rotating speed on the natural frequencies and modal dampings are discussed.

scholarly journals Material damping ratio from free-vibration method

2018 ◽  
Vol 50 (2) ◽  
pp. 83-97 ◽  
Author(s):  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Wojciech Sas ◽  
Alojzy Szymański
Keyword(s):  
Free Vibration ◽  
Damping Ratio ◽  
Strain Range ◽  
Material Damping ◽  
Soil Behavior ◽  
Torsional Mode ◽  
Equivalent Viscous Damping ◽  
Number Of Cycles ◽  
Definition Of ◽  
Equivalent Viscous Damping Ratio

Abstract One important aspect of soil dynamics is attenuation or energy loses. This inherent dynamic property is essential in the analysis of soil behavior subjected to a dynamic load. Energy absorption in soils leads to the definition of an equivalent viscous damping ratio (D). In resonant column testing there are commonly two different approaches in measuring material damping: during a steady-state vibration (SSV), when the specimen is vibrated at its first mode; and during free-vibration decay (FVD). The study reports results associated with the small to medium strain range material damping from FVD method, i.e. there is a cut off the constant vibration of the specimen at resonance and the specimen is allowed to free-vibration mode while the decay strain amplitude during free-vibration is calculated. The experiments were conducted on cohesive soils (sasiCl, Cl, clSa) from various test sites located in Warsaw, Poland. All the specimens were subjected to torsional mode of vibration at their first natural frequency, at different mean effective stress. The authors paid particular attention to the number of successive cycles after the free-vibration of the material is initiated. They examined various propositions from the literature and compare the received damping values using different number of cycles of vibration. The results showed that the most stable values of material damping ratio can be obtained by selecting each time a line of best fit on the authors’ choice of number of free-vibration cycles. However, the number of these cycles should not exceed 10.

Study on Equivalent Viscous Damping of Aeolian Vibration for Transmission Line by AACSR-400 Steel Core Aluminum Alloy Wire

2016 ◽  
Vol 723 ◽  
pp. 94-99 ◽  
Author(s):  
Bo Zhang ◽  
Wang Sheng Gong ◽  
Ze Hua Wang ◽  
Meng Ge Zhang ◽  
Lin Han ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Energy Balance ◽  
Transmission Line ◽  
Damping Ratio ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Alloy Wire ◽  
Equivalent Damping ◽  
Steel Core ◽  
Balance Principle

To ensure its operational security, it is important to study the vibration state of transmission line. The equivalent viscous damping of aero-vibration for a large-span overhead conductor is obligated to be determined. In this paper, the damping characteristics of conductor by AACSR-400 steel core aluminum alloy wire are studied by use of energy balance principle. Based on the Diana wind energy curve and equivalent viscous damping, the relationship between frequency and damping ratio is conducted and discussed. Furthermore, a numerical simulation by ANSYS is performed to verify the validity of the equivalent damping coefficient and equivalent damping ratio with the same material parameters. Study shows that the result of finite element method by ANSYS is consistent well with that by energy balance principle.

Beneficial performance of a quasi-zero stiffness vibration isolator with generalized geometric nonlinear damping

2020 ◽  
pp. 095745652097238
Author(s):  
Chun Cheng ◽  
Ran Ma ◽  
Yan Hu
Keyword(s):  
Damping Ratio ◽  
Nonlinear Damping ◽  
Vibration Isolator ◽  
Equivalent Damping ◽  
Frequency Responses ◽  
Geometric Nonlinear ◽  
Resonant Region ◽  
Force Transmissibility ◽  
Isolation Performance ◽  
Force And Displacement Transmissibility

Generalized geometric nonlinear damping based on the viscous damper with a non-negative velocity exponent is proposed to improve the isolation performance of a quasi-zero stiffness (QZS) vibration isolator in this paper. Firstly, the generalized geometric nonlinear damping characteristic is derived. Then, the amplitude-frequency responses of the QZS vibration isolator under force and base excitations are obtained, respectively, using the averaging method. Parametric analysis of the force and displacement transmissibility is conducted subsequently. At last, two phenomena are explained from the viewpoint of the equivalent damping ratio. The results show that decreasing the velocity exponent of the horizontal damper is beneficial to reduce the force transmissibility in the resonant region. For the case of base excitation, it is beneficial to select a smaller velocity exponent only when the nonlinear damping ratio is relatively large.

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