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.

scholarly journals Study on the Aging Time Variation Law of Mechanical Properties of the Laminated Rubber Bearing in Coastal Bridges considering Frictional Slip

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yue Li ◽  
Chongming Gao ◽  
Chong Li ◽  
Qian Li
Keyword(s):  
Mechanical Properties ◽  
Aging Time ◽  
Damping Ratio ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Coastal Bridges ◽  
Shape Coefficient ◽  
Rubber Bearings ◽  
Frictional Slip ◽  
Equivalent Viscous Damping Ratio

As an important support member in the structural system of coastal bridges, the frictional slip and the rubber aging of laminated rubber bearings will affect the service safety of the overall structure in earthquakes. In order to investigate the mechanical properties aging law of the rubber bearings considering frictional slip in the coastal bridges, a frictional slip experiment was carried out on the laminated rubber bearings. Moreover, the influence of rubber aging on the mechanical properties of the bearings with various shape coefficients was analyzed by the finite element method during the 100 years of service life of bridges. The results indicate that (1) the horizontal and vertical stiffness of the bearing increase linearly with the aging time of the rubber. The amplification of the bearing stiffness also grows with the shape coefficient of the bearing. (2) The frictional slip initiation displacement of the bearing grows with the rubber aging time. Furthermore, the larger the shape coefficient of the bearing is, the more the frictional slip initiation displacement of the bearing increases. (3) With the increase of the aging time, the equivalent viscous damping ratio of the bearing continues to increase and more energy is consumed by frictional slip. For the bearing with the shape coefficient of 16.38, the equivalent viscous damping ratio at 100 years of rubber aging time is 1.17 times higher than that of the initial state of the bearing, and 33.21% more energy is consumed through frictional slip. Given that the marine environment accelerates rubber aging and changes the mechanical properties, the effects of the frictional slip and rubber aging properties of the laminated rubber bearings on the seismic dynamic response of bridges should be considered in the seismic design of coastal bridges.

Predominant period and equivalent viscous damping ratio identification for a full-scale building shake table test

2017 ◽  
Vol 46 (14) ◽  
pp. 2459-2477 ◽  
Author(s):  
Michelle C. Chen ◽  
Rodrigo Astroza ◽  
José I. Restrepo ◽  
Joel P. Conte ◽  
Tara Hutchinson ◽  
...  
Keyword(s):  
Damping Ratio ◽  
Full Scale ◽  
Shake Table Test ◽  
Viscous Damping ◽  
Shake Table ◽  
Equivalent Viscous Damping ◽  
Predominant Period ◽  
Equivalent Viscous Damping Ratio

scholarly journals Simplified Vibration Model and analysis of a single-conductor transmission line with dampers

2016 ◽  
Vol 231 (22) ◽  
pp. 4150-4162 ◽  
Author(s):  
O Barry ◽  
R Long ◽  
DCD Oguamanam
Keyword(s):  
Transmission Line ◽  
Equations Of Motion ◽  
Frequency Equation ◽  
Mode Shapes ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Proposed Model ◽  
Vibration Model ◽  
Mass Spring ◽  
Discrete Mass

A novel model is developed for a vibrating single-conductor transmission line carrying Stockbridge dampers. Experiments are performed to determine the equivalent viscous damping of the damper. This damper is then reduced to an equivalent discrete mass-spring-mass and viscous damping system. The equations of motion of the model are derived using Hamilton’s principle and explicit expressions are determined for the frequency equation, and mode shapes. The proposed model is verified using experimental and finite element results from the literature. This proposed model excellently captures free vibration characteristics of the system and the vibration level of the conductor, but performs poorly in regard to the vibration of the counterweights.

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.

A New Method for the Identification of Coulomb and Viscous Friction

Tribology ◽  
2005 ◽  
Author(s):  
Lilan Liu ◽  
Hongzhao Liu ◽  
Ziying Wu ◽  
Daning Yuan
Keyword(s):  
Damping Ratio ◽  
Viscous Friction ◽  
Least Square Method ◽  
Least Square ◽  
New Method ◽  
Exponential Fitting ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Fitting Method ◽  
Friction Parameters

In this paper, a new method for simultaneously estimating Coulomb and viscous friction parameters from the free vibration of a damped oscillator is put forward. In the method, the nonlinear vibration equation with Coulomb and viscous friction is transformed into a linear procedure with equivalent viscous damping which is a function of velocity. The proposed method works well with both the displacement and velocity response data, while the case of zero velocity is not considered. From the displacement decaying curve, the equivalent viscous damping ratios are obtained by means of the local exponential fitting method, and different velocities corresponding to the equivalent viscous damping ratios are also obtained from the velocity decaying curve. Then, according to the relationship between the equivalent viscous damping ratio and the velocity, the Coulomb friction and the viscous damping are achieved using the least square method. The validity and accuracy of the proposed method are demonstrated through good simulation results.

scholarly journals Study on Equivalent Viscous Damping Coefficient of Sucker Rod Based on the Principle of Equal Friction Loss

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Qin Li ◽  
Bo Chen ◽  
Zhiqiang Huang ◽  
Haipin Tang ◽  
Gang Li ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Friction Loss ◽  
Damping Coefficient ◽  
Theoretical Formula ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Equivalent Damping ◽  
Rod System ◽  
Sucker Rod ◽  
Equivalent Damping Coefficient

Equivalent viscous damping coefficient is an important parameter of wave equation for sucker rod string. In this paper, based on the principle of equal friction loss, when the viscous energy consumption and the local damping energy consumption are taken into account, effects of equivalent viscous damping coefficients are obtained. Through deducing energy consumption equation of oil and energy consumption equation of the coupling, theoretical formula for equivalent damping coefficient of sucker rods is received. Results show that the smaller the K is (K is the ratio of sectional area of tubing to sucker rod), the larger the proportion of damping coefficient caused by viscous energy consumption in the equivalent damping coefficient of sucker rod system is. When K< 0.095, the proportion of damping coefficient caused by viscous energy consumption is more than 90%. Reducing the sudden change of cross-section area at sucker rod coupling has remarkable effect on reducing damping force of the sucker rod system. The research provides a theoretical basis for the application and design of sucker rod and tubing.

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.

Quality Factors of Rotors With Hydrodynamic Bearings

1993 ◽  
Vol 115 (2) ◽  
pp. 261-265 ◽  
Author(s):  
J. S. Rao
Keyword(s):  
Quality Factor ◽  
Damping Ratio ◽  
Maximum Amplitude ◽  
Viscous Damping ◽  
Quality Factors ◽  
Equivalent Viscous Damping ◽  
Hydrodynamic Bearings ◽  
At Resonance ◽  
Equivalent Viscous Damping Ratio ◽  
Undamped Natural Frequency

The quality factor of a system is a measure of the maximum amplitude of vibration that occurs at resonance when the frequency of excitation is equal to the undamped natural frequency. This factor can be easily determined for a given mode of vibration, given its equivalent viscous damping ratio, as Q = 1/2ξ. Such a definition becomes complicated for a rotor mounted on hydrodynamic bearings. This note discusses some factors involved in estimating the quality factor of a rotor.

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