scholarly journals Theoretical Investigation on the Impact of Two HDR Dampers on First Modal Damping Ratio of Stay Cable

2021 ◽  
Vol 11 (22) ◽  
pp. 10985
Author(s):  
Duy Thao Nguyen ◽  
Duy Hung Vo ◽  
Md. Naimul Haque
Keyword(s):  
Large Amplitude ◽  
Damping Ratio ◽  
Magnetorheological Damper ◽  
Design Parameters ◽  
Friction Damper ◽  
Stay Cable ◽  
Modal Damping Ratio ◽  
Stay Cables ◽  
High Damping Rubber ◽  
The Impact

Stay cables are one of the vital components of a cable-stayed bridge. Due to their flexible nature, stay cables are vulnerable to external excitation and often vibrate with large amplitude under wind action which leads to the fatigue failure of the cables. To suppress such kind of large amplitude vibration by improving the damping ratio of the cable various dampers such as magnetorheological damper, friction damper; oil damper; or high damping rubber (HDR) damper are utilized and gained popularity over time. This paper focuses on improving the damping ratio of stay cables using a combination of two HDR dampers. First, the theoretical model is formulated considering cable bending stiffness to evaluate the damping effect of cable-HDR dampers system. Then, the impact of various design parameters of HDR dampers on cable damping considering the cable stiffness is performed. The comparative analysis of results shows that the considered parameters such as loss factor, spring factor, and installation location of dampers have much effect on the stay cables damping ratio. Finally, the optimal parameters of the two HDR dampers are proposed for damper design.

Calculation on Modal Damping Ratio of Stay Cable Using Nonlinear Friction Damper

2012 ◽  
Vol 538-541 ◽  
pp. 1800-1803
Author(s):  
Hui Ping Wang
Keyword(s):  
Damping Ratio ◽  
Free Vibrations ◽  
Nonlinear Friction ◽  
Friction Damper ◽  
Stay Cable ◽  
Lumped Mass ◽  
Mass Model ◽  
Modal Damping Ratio ◽  
Stay Cables ◽  
Modal Damping

Stay cables of long span cable-stayed bridges are easy to vibrate under wind or wind/rain loads owning to their very low inherent damping. To install cable dampers near to the anchorages of cable has become a common practice for cable vibration control of cable-stayed bridge structures. In this study, the behaviors of a nonlinear frictional type of damper were investigated. The equations of motion of a cable with a friction damper were derived by using a lumped mass model. Then by introducing modal transformation, the analytical solution for the motion equations was obtained. The results show that the friction damper evokes linearly decaying of free vibrations of the cable as long as the damper does not lock the cable. The modal damping ratio of cable with the friction damper is strongly amplitude dependent. Calculation of modal damping ratio can be simplified using control parameter and the maximum modal damping ratio can be obtained. A universal estimation curve is proposed that is similar to linear viscous damper. These studies could provide design basis for the vibration mitigation of stay cables using nonlinear friction.

Theoretical Study on Cable’s Vibration Control by Single TMD

2014 ◽  
Vol 935 ◽  
pp. 211-214 ◽  
Author(s):  
Dong Liang ◽  
Ji Xiang Song
Keyword(s):  
Damping Ratio ◽  
Tuned Mass Damper ◽  
Design Parameters ◽  
Stay Cable ◽  
Coupling Vibration ◽  
Modal Damping Ratio ◽  
Modal Damping ◽  
Vibration Model ◽  
Mass Damper ◽  
Complex Models

The commonly used viscous dampers for cable’s vibration mitigation have some unfavorable factors, such as the damping effect is not obvious for super long stay cable, the limitation of installation position, coupling vibration, etc. The cable-tuned mass damper system vibration model is put forward to solve this problem. The optimal cable-tuned mass damper system modal damping ratio and optimum design parameters, including cable vibration order, TMD’s stiffness, TMD’s mass, and TMD’s damping, were obtained by the method of complex models. The results can provide important reference for the design of TMD for stay cable.

Experimental Study on Multi-Mode Vibration Control of a Stay Cable with a Passive Magnetorheological Damper

2013 ◽  
Vol 361-363 ◽  
pp. 1402-1405
Author(s):  
Zhi Hao Wang
Keyword(s):  
Vibration Control ◽  
Mr Damper ◽  
Magnetorheological Damper ◽  
Test Results ◽  
Stay Cable ◽  
Mr Dampers ◽  
Stay Cables ◽  
Modal Damping ◽  
Mode Vibration ◽  
Multi Mode

Effective vibration control technology for stay cables is extremely critical to safe operations of cable-stayed bridges. For super-long cables, passive linear damper cannot provide sufficient damping since it can be only optimum for a given mode of cable, while a long cable may vibrate with several modes. This paper focuses on multi-mode vibration control of stay cables with passive magnetorheological (MR) dampers. Firstly, a 21.6m-long model cable was designed and established in the laboratory.Then, control performance of the cable with a passive MR damper was tested. The test results show that modal damping ratios of the cable in the first four modes can be improved significantly with the MR damper. It is further demonstrated that optimal tuned passively operated MR damper can outperform the passive viscous damper.

scholarly journals Parametric Study and Uncertainty Quantification of the Nonlinear Modal Properties of Frictional Dampers

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Yekai Sun ◽  
Jie Yuan ◽  
Luca Pesaresi ◽  
Enora Denimal ◽  
Loïc Salles
Keyword(s):  
Contact Angle ◽  
Damping Ratio ◽  
Energy Levels ◽  
Design Stage ◽  
Design Parameters ◽  
Vertical Position ◽  
Beam Model ◽  
Friction Damper ◽  
Resonant Amplitude ◽  
Two Parameters

Abstract A numerical methodology is described to study the influence of the contact location and contact condition of friction damper in aircraft engines. A simplified beam model is used to represent the blade for the preliminary design stage. The frictional damper is numerically analyzed based on two parameters, contact angle and vertical position of the platform. The nonlinear modal analysis is used to investigate the nonlinear dynamic behavior and damping performances of the system. The harmonic balanced method with the continuation technique is used to compute the nonlinear modes for a large range of energy levels. By using such a modeling strategy, the modal damping ratio, resonant amplitude, and resonant frequency are directly and efficiently computed for a range of design parameters. Monte Carlo simulations together with Latin hypercube sampling is then used to assess the robustness of the frictional damper, whose contact parameters involve much uncertainties due to manufacturing tolerance and also wear effects. The influences of those two parameters are obtained, and the best performances of the frictional damper can be achieved when the contact angle is around 25 deg–30 deg. The vertical position of the platform is highly mode dependent, and other design considerations need to be accounted. The results have proved that the uncertainties that involved contact surfaces do not have significant effects on the performance of frictional damper.

Dynamic Characteristics of Steel Stay Cable in Civil Engineering Using Field Testing

2013 ◽  
Vol 634-638 ◽  
pp. 2770-2773
Author(s):  
Chern Hwa Chen ◽  
Yuh Yi Lin
Keyword(s):  
Civil Engineering ◽  
Slenderness Ratio ◽  
Damping Ratio ◽  
Field Testing ◽  
Dynamic Responses ◽  
Ambient Vibration ◽  
Stay Cable ◽  
Flexural Stress ◽  
Cable Stayed Bridge ◽  
Stay Cables

The stay cables in civil engineering are one of the most difficult components to maintain for the safety of bridge after it is open for traffic, as the slenderness ratio is large, and they are flexible, low in damping ratio and less resistant to bending. It is possible that the cable snaps under large cyclic flexural stress due to wind-induced motion, regular traffic or even ambient vibration. The loosening seal of stay cables, damaged anchors, and tendon corrosion due to damaged protection sleeve at the root will undermine dramatically the life of cable-stayed bridge and even its safety. In this paper, the field test used to determine dynamic responses for stayed cable of the bridge in civil engineering. The practice formula is used to determine the cable forces of the Kao Ping Hsi cable-stayed bridge (the largest cable-stayed bridge in Taiwan). The results obtained herein indicate that such analysis is valid and rational, and may be used to monitor the safety of cable-stayed bridge.

Damping of Stay Cable-Passive Damper System with Effects of Cable Bending Stiffness and Damper Stiffness

2012 ◽  
Vol 204-208 ◽  
pp. 4513-4517 ◽  
Author(s):  
Min Liu ◽  
Guang Qiao Zhang
Keyword(s):  
Numerical Analysis ◽  
Damping Ratio ◽  
Bending Stiffness ◽  
Damping Coefficient ◽  
Stay Cable ◽  
Modal Damping Ratio ◽  
Passive Damper ◽  
Modal Damping ◽  
Optimal Damping ◽  
Coefficient Increase

In the present paper, the asymptotic solution of modal damping ratio of stay cable-passive damper system with the influence of cable bending stiffness and damper stiffness was derived. Maximum modal damping ratio and corresponding optimal damping coefficient, which indicated the relationships of the characteristics of the damper and the cable bending stiffness was theoretically analyzed to obtain their close solutions. On the basis of these close solutions, numerical analysis of modal damping of stay cable-passive damper system with the effects of cable bending stiffness and damper stiffness was conducted. The numerical and analytical results show that the maximum modal damping ratio decrease and the corresponding damping coefficient increase, when considering the influence of the damper stiffness and the cable bending stiffness.

Vibration Analysis and Methods of Dry Friction Damping of Tubed Vortex Reducer

2020 ◽  
Author(s):  
Siyuan Chen ◽  
Yanrong Wang ◽  
Dasheng Wei ◽  
Yanbin Luo ◽  
Shimin Gao
Keyword(s):  
Dry Friction ◽  
Vibration Analysis ◽  
Damping Ratio ◽  
Vibration Reduction ◽  
Vibration Characteristics ◽  
Design Parameters ◽  
Vibration Test ◽  
Friction Damping ◽  
The Impact ◽  
Dry Friction Damping

Abstract The tubed vortex reducer is a new structure of aero-engine, which is widely used in advanced large bypass ratio high performance turbofan engines. It is usually installed between the rear two-stage discs of the high-pressure compressor, and reduces the generation of free vortex by restricting the flow path of the cooling airflow, thereby reducing the pressure loss of the cooling airflow and improving the engine efficiency. In this paper, vibration analysis of tubed vortex reducer is carried out by experiments and numerical simulations. Using the finite element method, the natural vibration characteristics of the vortex reducer are calculated with ANSYS. The sensitivity analysis of the impact of design parameters on the vibration characteristics is carried out. In addition, the vibration test bench of the vortex reducer is set up, and the vibration test of the vortex reducer is conducted by means of frequency sweeping and hammer hitting respectively. The experimental results satisfactorily reproduce the simulation results. Then the theoretical model of dry friction damping of vortex reducer is established. Based on the dynamic model of the complex contact system composed of vortex reducer and damping sleeve, the relationship between energy dissipation in different directions is derived. And a method evaluating the performance of vibration reduction is presented for calculating its equivalent damping ratio. Finally, the influence of the key design parameters and different installation methods on the damping ratio is analyzed. Overall, this work can provide reference for vibration reduction design and optimization of vortex reducer.

scholarly journals Automated Real-Time Assessment of Stay-Cable Serviceability Using Smart Sensors

2019 ◽  
Vol 9 (20) ◽  
pp. 4469 ◽  
Author(s):  
Seunghoo Jeong ◽  
Young-Joo Lee ◽  
Do Hyoung Shin ◽  
Sung-Han Sim
Keyword(s):  
Real Time ◽  
Damping Ratio ◽  
Assessment System ◽  
Smart Sensors ◽  
Stay Cable ◽  
Long Span Bridges ◽  
Long Span ◽  
Stay Cables ◽  
High Flexibility ◽  
Cable Stayed Bridges

The number of cable-stayed bridges being built worldwide has been increasing owing to the increasing demand for long-span bridges. As the stay-cable is one of critical load-carrying members of cable-stayed bridges, its maintenance has become a significant issue. The stay-cable has an inherently low damping ratio with high flexibility, which makes it vulnerable to vibrations owing to wind, rain, and traffic. Excessive vibration of the stay-cable can cause long-term fatigue problems in the stay-cable as well as the cable-stayed bridge. Therefore, civil engineers are required to carry out maintenance measures on stay-cables as a high priority. For the maintenance of the stay-cables, an automated real-time serviceability assessment system using wireless smart sensors was developed in this study. When the displacement of the cable in the mid-span exceeds either the upper or the lower bound provided in most bridge design codes, it is considered as a serviceability failure. The system developed in this study features embedded on-board processing, including the measurement of acceleration, estimation of displacement from measured acceleration, serviceability assessment, and monitoring through wireless communication. A series of laboratory tests were carried out to verify the performance of the developed system.

Research on the Modal Damping Ratio for Stay Cable with Viscoselasticity Damper in Cable-Stayed Bridges

2013 ◽  
Vol 779-780 ◽  
pp. 671-674
Author(s):  
Shui Sheng Chen ◽  
De Shan Wang
Keyword(s):  
Damping Ratio ◽  
Bending Stiffness ◽  
Complex Eigenvalue ◽  
Stay Cable ◽  
Modal Damping Ratio ◽  
Modal Damping ◽  
Out Of Plane ◽  
Damper Design ◽  
Inclined Angle ◽  
Separation Strategy

Taking the bending stiffness, cable static sag and cable inclined angle into consideration, equations of space free vibration of the cable-damper system are derived in this paper. Joining the variable separation strategy and center difference method, the partial differential equations are discretized in space and a set of complex eigenvalue equations, which are solved by state space method, are derived, and both the maximum modal damping ration and the optimal damper parameter are obtained. Several typical stay cables are investigated for both the in-plane and out-of-plane modes under different cable parameters and damper parameters. The results demonstrate that modal damping ratio for the first in-plane mode is significantly affected by the cable static sag only, but those for the other modes affected by cable sag are slight, and cable static sag do not affect the optimal damper parameter for all modes, however the bending stiffness will changes both the maximum modal damping ratios and the optimal damper parameters. Some valuable suggestions are proposed for the optimal damper design.

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