The Experts below are selected from a list of 1938 Experts worldwide ranked by ideXlab platform
Chao Zhang - One of the best experts on this subject based on the ideXlab platform.
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Simplified analysis of cable-stayed bridges with longitudinal viscous dampers
Engineering Construction and Architectural Management, 2020Co-Authors: Xiaoyi Zhang, Jianfeng Gao, Chao ZhangAbstract:PurposeViscous dampers are commonly used in large span cable-stayed bridges to mitigate seismic effects and have achieved great success.Design/methodology/approachHowever, the nonlinear analysis on damper parameters is usually computational intensive and nonobjective. To address these issues, this paper proposes a simplified method to determine the viscous damper parameters for double-tower cable-stayed bridges. An empirical formula of the Equivalent Damping Ratio of viscous dampers is established through decoupling nonclassical Damping structures and linearization of nonlinear viscous dampers. Shaking table tests are conducted to verify the feasibility of the proposed method. Moreover, this simplified method has been proved in long-span cable-stayed bridges.FindingsThe feasibility of this method is verified by the simplified model shaking table test. This simplified method for determining the parameters of viscous dampers is verified in cable-stayed bridges with different spans.Originality/valueThis simplified method has been validated in cable-stayed bridges with various spans.
Xiaoyi Zhang - One of the best experts on this subject based on the ideXlab platform.
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Simplified analysis of cable-stayed bridges with longitudinal viscous dampers
Engineering Construction and Architectural Management, 2020Co-Authors: Xiaoyi Zhang, Jianfeng Gao, Chao ZhangAbstract:PurposeViscous dampers are commonly used in large span cable-stayed bridges to mitigate seismic effects and have achieved great success.Design/methodology/approachHowever, the nonlinear analysis on damper parameters is usually computational intensive and nonobjective. To address these issues, this paper proposes a simplified method to determine the viscous damper parameters for double-tower cable-stayed bridges. An empirical formula of the Equivalent Damping Ratio of viscous dampers is established through decoupling nonclassical Damping structures and linearization of nonlinear viscous dampers. Shaking table tests are conducted to verify the feasibility of the proposed method. Moreover, this simplified method has been proved in long-span cable-stayed bridges.FindingsThe feasibility of this method is verified by the simplified model shaking table test. This simplified method for determining the parameters of viscous dampers is verified in cable-stayed bridges with different spans.Originality/valueThis simplified method has been validated in cable-stayed bridges with various spans.
Nguyen Thi Ngoc - One of the best experts on this subject based on the ideXlab platform.
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study on the variation characteristics of vertical Equivalent Damping Ratio of tire soil system using semi empirical model
Journal of Terramechanics, 2014Co-Authors: Sihong Zhu, Do Minh Cuong, Nguyen Thi NgocAbstract:Abstract Prediction and determination of the Damping Ratio of a tire–soil system is very important to the design of the suspension system of the tractor. With this aim, a test rig was designed and developed to measure the vertical Equivalent Damping Ratio of tire–soil system using Free-VibRation Logarithmic Decay Method. The test was performed with three kinds of tractor tire using a combination of five inflation pressure levels, three soil depths and four soil moisture contents in the paddy soil. The results revealed that the vertical Equivalent Damping Ratio of tire–soil increases with the increase in soil depth and decreases with the increase in tire inflation pressure. It also increases with relative increase in soil moisture contents (observed at 37.9%, 48.8% and 66.7% soil moisture content) then decreases as soil moisture content is too high (observed at 77.4% soil moisture content). So, it is concluded that the vertical Equivalent Damping Ratio of tire–soil system is evidently dependent on tire inflation pressure, soil moisture content and soil depth. These have to be noticed and used in design parameters of tractor suspension system.
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Study on the variation characteristics of vertical Equivalent Damping Ratio of tire–soil system using semi-empirical model
Journal of Terramechanics, 2014Co-Authors: Do Minh Cuong, Sihong Zhu, Nguyen Thi NgocAbstract:Prediction and determination of the Damping Ratio of a tire–soil system is very important to the design of the suspension system of the tractor. With this aim, a test rig was designed and developed to measure the vertical Equivalent Damping Ratio of tire–soil system using Free-VibRation Logarithmic Decay Method. The test was performed with three kinds of tractor tire using a combination of five inflation pressure levels, three soil depths and four soil moisture contents in the paddy soil. The results revealed that the vertical Equivalent Damping Ratio of tire–soil increases with the increase in soil depth and decreases with the increase in tire inflation pressure. It also increases with relative increase in soil moisture contents (observed at 37.9%, 48.8% and 66.7% soil moisture content) then decreases as soil moisture content is too high (observed at 77.4% soil moisture content). So, it is concluded that the vertical Equivalent Damping Ratio of tire–soil system is evidently dependent on tire inflation pressure, soil moisture content and soil depth. These have to be noticed and used in design parameters of tractor suspension system.
Do Minh Cuong - One of the best experts on this subject based on the ideXlab platform.
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study on the variation characteristics of vertical Equivalent Damping Ratio of tire soil system using semi empirical model
Journal of Terramechanics, 2014Co-Authors: Sihong Zhu, Do Minh Cuong, Nguyen Thi NgocAbstract:Abstract Prediction and determination of the Damping Ratio of a tire–soil system is very important to the design of the suspension system of the tractor. With this aim, a test rig was designed and developed to measure the vertical Equivalent Damping Ratio of tire–soil system using Free-VibRation Logarithmic Decay Method. The test was performed with three kinds of tractor tire using a combination of five inflation pressure levels, three soil depths and four soil moisture contents in the paddy soil. The results revealed that the vertical Equivalent Damping Ratio of tire–soil increases with the increase in soil depth and decreases with the increase in tire inflation pressure. It also increases with relative increase in soil moisture contents (observed at 37.9%, 48.8% and 66.7% soil moisture content) then decreases as soil moisture content is too high (observed at 77.4% soil moisture content). So, it is concluded that the vertical Equivalent Damping Ratio of tire–soil system is evidently dependent on tire inflation pressure, soil moisture content and soil depth. These have to be noticed and used in design parameters of tractor suspension system.
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Study on the variation characteristics of vertical Equivalent Damping Ratio of tire–soil system using semi-empirical model
Journal of Terramechanics, 2014Co-Authors: Do Minh Cuong, Sihong Zhu, Nguyen Thi NgocAbstract:Prediction and determination of the Damping Ratio of a tire–soil system is very important to the design of the suspension system of the tractor. With this aim, a test rig was designed and developed to measure the vertical Equivalent Damping Ratio of tire–soil system using Free-VibRation Logarithmic Decay Method. The test was performed with three kinds of tractor tire using a combination of five inflation pressure levels, three soil depths and four soil moisture contents in the paddy soil. The results revealed that the vertical Equivalent Damping Ratio of tire–soil increases with the increase in soil depth and decreases with the increase in tire inflation pressure. It also increases with relative increase in soil moisture contents (observed at 37.9%, 48.8% and 66.7% soil moisture content) then decreases as soil moisture content is too high (observed at 77.4% soil moisture content). So, it is concluded that the vertical Equivalent Damping Ratio of tire–soil system is evidently dependent on tire inflation pressure, soil moisture content and soil depth. These have to be noticed and used in design parameters of tractor suspension system.
Kyung-won Min - One of the best experts on this subject based on the ideXlab platform.
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Optimal shape of LCVA for vibRation control of structures subjected to along wind excitation
Smart Structures and Systems, 2012Co-Authors: Jihun Park, Kyung-won MinAbstract:In this study, a procedure to design an optimal LCVA that maximizes the Equivalent Damping Ratio added to the primary structure subjected to along-wind excitation is proposed. That design procedure does not only consider the natural frequency and Damping Ratio of the LCVA, but also the proportion of the U-shaped liquid, which is closely related to the participation Ratio of the liquid mass in inertial force. In addition, constraints to ensure the U-shape of the liquid are considered in the design process, so that suboptimal solutions that violate the optimal tuning law partly are adopted as a candidate of the optimal LCVA. The proposed design procedure of the LCVA is applied to the control of the 76-story benchmark building, and the optimal proportions of the liquid shape under various design conditions are compared.
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Equivalent Damping Ratio based on earthquake characteristics of a sdof structure with an mr damper
Transactions of The Korean Society for Noise and Vibration Engineering, 2008Co-Authors: Byoungwook Moon, Jihun Park, Sungkyung Lee, Kyung-won MinAbstract:Seismic control performance of MR dampers, which have severe nonlinearity, varies with respect to the dynamic characteristics of an earthquake such as magnitude, frequency and duRation. In this study, the effects of excitation characteristics on the Equivalent linear system of a building structure with the MR damper are investigated through numerical analysis for artificial ground motions generated from different response spectrums. The Equivalent Damping Ratio of the structure with the MR damper is calculated using Newmark and Hall`s equations for ground motion amplification factors. It is found that the Equivalent Damping Ratio of the structure with the MR damper is dependent on the Ratio of the maximum friction force of the MR damper over excitation magnitude. Frequency contents of the earthquake ground motion affects the Equivalent Damping Ratio of long-period structures considerably. Also, additional Damping effect caused by interaction between the viscousity and friction of the MR damper is observed. Finally. response reduction factors for Equivalent linear systems are proposed in order to improve accuracy in the prediction of the actual nonlinear response.
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Evaluation of Equivalent Damping Ratio of a structure with added dampers
Engineering Structures, 2004Co-Authors: Sang-hyun Lee, Kyung-won Min, Jae-seung Hwang, Jinkoo KimAbstract:The purpose of this study is to propose a new method for evaluating the Equivalent Damping Ratio of a structure with supplemental Damping devices to assess the vibRation control effect quantitatively. The modal-energy-formed Lyapunov function is defined first, and the Riccati matrix and Damping rate parameter are derived. Then from its analogy with the definition of a viscous modal Damping Ratio, the Equivalent Damping Ratio is defined. The proposed approach is applied to estimate the Equivalent Damping Ratio of a structure with various added Damping devices. Then a closed-form solution is derived to obtain an Equivalent modal Damping Ratio without carrying out numerical analysis. Results from the numerical analysis verify that the proposed method provides an Equivalent Damping Ratio of a structure equipped with nonlinear as well as linear Damping devices quite accurately.
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Equivalent Damping of a structure with vibRation control devices subjected to wind loads
Wind and Structures, 2003Co-Authors: Jae-seung Hwang, Sang-hyun Lee, Jinkoo Kim, Kyung-won MinAbstract:The purpose of this study is to propose a procedure for evaluating quantitatively the increase of the Equivalent Damping Ratio of a structure with passive/active vibRation control systems subjected to a stationary wind load. A Lyapunov function governing the response of a structure and its differential equation are formulated first. Then the state-space equation of the structure coupled with the secondaryrnDamping system is solved. The results are substituted into the differential equation of the Lyapunov function and its derivative. The Equivalent Damping Ratios are obtained from the Lyapunov function of the combined system and its derivative, and are used to assess the control effect of various Damping devicesrnquantitatively. The accuracy of the proposed procedure is confirmed by applying it to a structure with nonlinear as well as linear passive/active control systems.
