• Title/Summary/Keyword: Rubber Damper

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Consideration of Frequency Dependent Complex Stiffness of Rubber Busings in Transmission Force Analysis of a Vehicle Suspension System (고무 부싱의 주파수 의존 복소 강성을 고려한 차량 현가 장치에서의 전달력 분석)

  • 이준화;김광준
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1998.04a
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    • pp.34-39
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    • 1998
  • In order to compute the forces which are transmitted through rubber bushings with a commercial multibody dynamic analysis (MBDA) program, a rubber bushing model is needed. The rubber bushing model of MBDA programs such as DADS or ADAMS is the Voigt model which is simply a parallel spring-viscous damper system, meaning that the damping force of the Voigt model is proportional to the frequency. However, experiments do not necessarily support this proportionality. Alternatively, the viscoelastic characteristics of rubber bushings can be better represented by the complex stiffness. The purpose of this paper is to develop a viscoelastic rubber bushing model for the MBDA programs. Firstly, a methodology is proposed to calculate the complex stiffness of rubber bushings considering static and dynamic load conditions. Secondly, a viscoelastic rubber bushing model developed which uses standard elements provided by DADS. The proposed methods are applied to the rubber bushings of the lower control arms of a rear suspension of a 1994 Ford Taurus model. Then, the forces computed for the rubber bushing model are analyzed and compared with the Voigt model in time and frequency domains.

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Cyclic compressive behavior of polyurethane rubber springs for smart dampers

  • Choi, Eunsoo;Jeon, Jong-Su;Seo, Junwon
    • Smart Structures and Systems
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    • v.20 no.6
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    • pp.739-757
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    • 2017
  • The main goal of this study is to investigate the hysteretic behavior of polyurethane rubber springs in compression with and without precompression. The precompression is introduced to provide rigid force in the behavior, and thereby a precompressed rubber spring can be used for a restoring element. For the goal, this study prepares nine rubber springs for three suites which are all cylindrical in shape with a hole at the center. The rubber springs in each suite have different dimensions of diameter and length but have similar shape factors; thus, they are designed to have a similar compressive stiffness. Three rubber springs from the nine are tested with increasing compressive strain up to 30% strain to investigate the behavior of the rubber springs without precompression as well as the effect of the loading strain. The nine springs are compressed up to 30% strain with increasing precompressive strain from 0 to 20% at increments of 5%. The study analyzes the effective stiffness and damping ratio of the rubber springs with and without precompression, and the rigid force of the precompressed rubber springs is discussed. Finally, this study suggests a regression method to determine the minimum required precompression to eliminate residual strain after unloading.

Shape Optimization of Uniaxial Vibrating Metal Damper (일축 진동형 금속제진장치 형상 최적설계)

  • Yoon, Ji-Hoon;Park, Ji-Woon;Lim, Yun-Mook;Yoon, Gil-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.4
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    • pp.313-318
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    • 2017
  • This study performs the structural analysis and the optimum design of a vibrating metal damper to absorb vibration energy. Unlike other dampers such as rubber bearing, friction or viscose dampers, the present vibrating metal damper utilizes the plastic deformation of a steel and its associated hysteresis phenomenon to reduce vibrations of structures. To optimize this vibrating metal damper, it is important to obtain plastic deformation through the damper. To achieve this, the shape optimization method is developed and applied to find out optimal envelopes of the metal damper. Depending on the parameterization scheme, some novel optimal shapes can be found.

Analytical Study to Determine the Dynamic Property of Control Equipment Room using LRB (납-고무베어링을 적용한 제어장치의 동적평가를 위한 해석적 연구)

  • 김우범;김대곤;이경진;박병구
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.09a
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    • pp.473-480
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    • 2003
  • In these days, The base isolation system is often used improve the seismic capacity of the structure Instead of conventional techniques of strengthening the structural members. The purpose of this study is to evaluate dynamic property evaluation of control equipment using Lead Rubber Bearing. In this study, analysis numerical was performed to determine the optimal dynamic property of lead rubber bearing and damper which minimize the response of base from in main control room. Also the analytical results was composed with the test results peformed in previous study

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The Transmissibility of the Compact Disc Player due to Temperature (온도변화에 기인한 컴팩트디스크 플레이어의 전달율)

  • Kim, Byoung-Sam;Lee, Tae-Keun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.207-211
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    • 2009
  • To investigate the vibration characteristics of compact disc player(CDP) due to excited vibration and disturbances, it is necessary to consider the transmissibility of the CDP. The disturbances as well as the temperature in the vehicle are the one of the important factors when CDP is designed. In this study, the effect on the temperature of the oil damper, which is applied to anti-vibration system of the CDP, was investigated. When the temperature was changed from -30 to 90 and the properties of the oil damper (hardness of rubber, viscosity of oil) were changed, the transmissibility was measured.

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Improvement of dynamic characteristics of optical pick-up actuator using ferrofluidic damper (자성유체 댐퍼를 이용한 광픽업 액츄에이터의 동특성 개선)

  • 송병륜;신경식;김진기;남도선;성평용;이주형
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.496-503
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    • 2001
  • The suspension of the optical pickup actuator is damped by the presence of silicone rubber damper bond at its termination. In spite of the presence of it, the actuator still exhibits a strong mechanical resonance which affects its settling time and vibrational characteristics. This resonance can cause errors in reading information from the disk, particularly in high speed CD-ROM and DVD-ROM drives. Ferrofluids are stable colloidal suspensions of sub-micron sized magnetic particles in a carrier liquid. In the actuator design, ferrofluid is applied to the surface of the magnets until the quantity is sufficient to maintain intimate contact with the bobbin/carrier assembly. The fluid is retained in the magnetic field and its viscosity provides the desired mechanical damping to the moving assembly, improving the actuators settling time and vibrational characteristics. Access time is also improved, particularly on warped or eccentric discs.

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A Tuned Liquid Mass Damper(TLMD) for Controlling Bi-directional Responses of a Building Structure (건축구조물의 2방향 진동제어를 위한 동조액체질량감쇠기)

  • Heo, Jae-Sung;Park, Eun-Churn;Lee, Sang-Hyun;Lee, Sung-Kyung;Kim, Hong-Jin;Cho, Bong-Ho;Jo, Ji-Seong;Kim, Dong-Young;Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.3
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    • pp.345-355
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    • 2008
  • This paper presents a design of a tuned liquid mass damper(TLMD) for controlling bi-directional response of high-rise building structure subjected to windload. The proposed damper behaves as a tuned mass damper(TMD) of which mass is regarded as the mass of a tuned liquid column damper(TLCD) and the case wall of the TLCD itself in one direction and the TLCD in the other direction. Because the proposed device has coupled design parameter along two orthogonal directions, it is very important to select designing components by optimal fine tuning. In the designing TLMD, for easy maintenance, the rubber-bearing with small springs was applied in TMD direction. In this study, the Songdo New City Tower 1A in Korea, which has been designed and constructed two TLCDs in order to control bi-directional response, was chosen as the model building structure. The results of rotation test proved the effectiveness of bi-directional behavior of TLMD.

The effect of base isolation and tuned mass dampers on the seismic response of RC high-rise buildings considering soil-structure interaction

  • Kontoni, Denise-Penelope N.;Farghaly, Ahmed Abdelraheem
    • Earthquakes and Structures
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    • v.17 no.4
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    • pp.425-434
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    • 2019
  • The most effective passive vibration control and seismic resistance options in a reinforced concrete (RC) high-rise building (HRB) are the base isolation and the tuned mass damper (TMD) system. Many options, which may be suitable or not for different soil types, with different types of bearing systems, like rubber isolator, friction pendulum isolator and tension/compression isolator, are investigated to resist the base straining actions under five different earthquakes. TMD resists the seismic response, as a control system, by reducing top displacement or the total movement of the structure. Base isolation and TMDs work under seismic load in a different way, so the combination between base isolation and TMDs will reduce the harmful effect of the earthquakes in an effective and systematic way. In this paper, a comprehensive study of the combination of TMDs with three different base-isolator types for three different soil types and under five different earthquakes is conducted. The seismic response results under five different earthquakes of the studied nine RC HRB models (depicted by the top displacement, base shear force and base bending moment) are compared to show the most suitable hybrid passive vibration control system for three different soil types.

Influence of the deteriorated anti-seismic devices on seismic performance and device behavior of continuous girder bridges

  • Shangtao Hu;Renkang Hu;Menggang Yang;Dongliang Meng
    • Earthquakes and Structures
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    • v.24 no.5
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    • pp.333-343
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    • 2023
  • Various seismic isolation and reduction devices have been applied to suppress the longitudinal vibration of continuous girder bridges. As representative devices, lead rubber bearing (LRB) and fluid viscous damper (FVD) might suffer from deterioration during the long-term service. This study aims to evaluate the impact of device deterioration on the seismic responses of continuous girder bridges and investigate the seismic behavior of deteriorated LRBs and FVDs. Seismic performance of a simplified bridge model was investigated, and the influence of device deterioration was evaluated by the coefficient of variation method. The contribution of LRB and FVD was assessed by the Sobol global sensitivity analysis method. Finally, the seismic behaviors of deteriorated LRBs and FVDs were discussed. The result shows that (i) the girder-pier relative displacement is the most sensitive to the changes in the deterioration level, (ii) the deterioration of FVD has a greater effect on the structural responses than that of LRB, (iii) FVD plays a major role in energy dissipation with a low degradation level while LRB is more essential in dissipating energy when suffering from high degradation level, (iv) the deteriorated devices are more likely to reach the ultimate state and thus be damaged.

The Application of Resettable Device to Semi-Active Tuned Mass Damper Building Systems for Multi-level Seismic Hazard Mitigation

  • Chey, Min-Ho
    • Architectural research
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    • v.14 no.3
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    • pp.99-108
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    • 2012
  • An innovative multi-story Semi-Active Tuned Mass Damper (SATMD) building system is proposed to control seismic response of existing structures. The application of adding new stories as large tuned mass and semi-active (SA) resettable actuators as central features of the control scheme is derived. For the effective control of the structures, the optimal tuning parameters are considered for the large mass ratio, for which a previously proposed equation is used and the practical optimal stiffness is allocated to the actuator stiffness and rubber bearing stiffness. A two-degree-of freedom (2-DOF) model is adopted to verify the principal efficiency of the suggested structural control concept. The simulations for this study utilizes the three ground motions, from SAC project, having probability of exceedance of 50% in 50 years, 10% in 50 years, and 2% in 50 years for the Los Angeles region. 12-story moment resisting frames, which are modified as '12+2' and '12+4' story structures, are investigated to assess the viability and effectiveness of the system that aims to reduce the response of the buildings to earthquakes. The control ability of the SATMD scheme is compared to that of an uncontrolled and an ideal Passive Tuned Mass Damper (PTMD) building system. From the performance results of suggested '12+2' and '12+4' story retrofitting case studies, SATMD systems shows significant promise for application of structural control where extra stories might be added.