• Title, Summary, Keyword: Bingham 모델

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Manufacturing of MR Dampers and Estimation of the Bingham Model Parameters (MR 댐퍼의 제작과 Bingham 모델의 매개변수 추정)

  • Lee, Gun-Myung;Park, Mun-Soo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.6
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    • pp.82-87
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    • 2014
  • Small MR dampers with a simple structure were designed and manufactured. The Bingham model was used to represent the dynamic characteristics of the damper, and the parameters of the model were estimated from experimental data which were obtained by harmonic tests. The value of the estimated yield shear force remains positive when no electric current is applied, and it increases slowly with the current. The estimated viscous damping coefficient has a value close to zero when no electric current is applied, and it increases almost linearly with the current.

Performance Evaluation of MR Damper using Equivalent Linearization Technique (선형화 기법을 이용한 MR 감쇠기 성능평가)

  • Lee, Sang-Hyun;Min, Kyung-Won;Lee, Myoung-Kyu
    • Journal of the Earthquake Engineering Society of Korea
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    • v.9 no.2
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    • pp.1-6
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    • 2005
  • The purpose of this paper is to evaluate the performance of an MR fluid damper for seismic vibration control of a structure in terms of equivalent linear damping based on linearization technique and to experimentally verify the results from linearization technique by comparing them to those from system identification testing of a building structure with the MR damper. First, among various models for the MR damper, the equivalent damping is estimated for the Bingham model which is mathematically simple. Second, the transfer function of a building structure with the MR damper is obtained by performing shaking table tests and the damping matrices of the structure are constructed using the modal information obtained by the transfer function. It is observed that the damping mathematically estimated using linearization technique for the Bingham model matches well with the damping coefficient experimentally obtained by system identification.

An Analysis of Debris Flow Movements Using Rheological Model (레올로지 모델을 이용한 토석류 이동해석)

  • 김상규;서흥석
    • Geotechnical Engineering
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    • v.13 no.5
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    • pp.133-144
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    • 1997
  • It was proved from the viscosity test for deposits of debris flows(Kim and Seo, 1997) that the property of debris flows could be represented as Bingham plastic model. Based on this bahavior, numerical analysis for the movement of debris flows is carried out by using a computer progran Polyflow which huts been developed for the analysis of the behavior of non-Newtonian fluid. The numerical results obtained from two sites agree well with the movement predicted by an empirical formula. It can be concluded, therefore. that this scheme can be used for the analysis of the movement of debris flow.

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Bingham Properties and Damping Force Control of an ER Fluid under Squeeze Mode (압착모드하에서 ER유체의 빙햄특성 및 댐핑력 제어)

  • 홍성룡;최승복
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.11
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    • pp.37-45
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    • 2002
  • This paper presents the field-dependent Bingham characteristics and damping force control of an electro-rheological (ER) fluid under squeeze mode operation. The squeeze force of the ER fluid due to the imposed electric field is analyzed and an appropriate size of the disk-type electrode is devised. On the basis of the theoretical model of the ER fluid under squeeze mode operation, the yield stress and response speed of the ER fluid are distilled from the time responses of squeeze force to the step electric potentials. Measured squeeze forces under various excitation conditions are compared with the predicted ones from Bingham model and time constant obtained at the transient response test. In addition, the controllability of the field-dependent damping force of the ER fluid under squeeze mode is experimentally demonstrated by implementing simple PID controller.

Response Reduction of a SDOF Structure based on Friction Force Ratio of MR Controller (MR제어기의 마찰력비에 따른 단자유도 구조물의 응답감소)

  • Seong, Ji-Young;Min, Kyung-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.4
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    • pp.435-443
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    • 2010
  • This study presents key parameters for the structure installed with MR controller in reducing its responses. MR controller is regarded as Bingham model of which control forces are frictional and viscous ones. The parameters are identified as friction force ratios, $R_f$ and $R_h$ which are, respectively, ratio of MR controller friction force to static restoring force for free vibration and ratio of the friction force to amplitude of harmonic force. Structure-MR controller system shows nonlinear response behavior due to friction force. Energy balance strategy is adopted to transform the behavior to linear one with equivalent damping ratio. Finally, proposed equivalent linear process is compared to the nonlinear one, which turns out to give acceptably good results.

Dynamic Modeling of Semi-active Squeeze Mode MR Damper for Structural Vibration Control (구조물의 진동 제어를 위한 압착식 MR 감쇠기의 동적 모델링)

  • Heo, Gwang-Hee;Jeon, Joon-Ryong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.2
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    • pp.172-180
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    • 2009
  • Normally in order to build a semi-active control system equipped with MR damper, the dynamic modeling of the damper is required to numerically predict its dynamic damping force and also its behavioral characteristics. For the dynamic modeling of the MR damper, this paper attempts to predict and evaluate its dynamic behavior by applying specifically both a power model and a Bingham model. Dynamic loading tests were performed on the squeeze type of damper specially designed for this research, and force-displacement hysteresis loops confirmed the effectiveness of the damper as a semi-active control device. In the meantime, in order to evaluate the effectiveness of each model applied, the model parameter for each model was identified. On the basis of the parameter, we derived the error ratio of the force-velocity relationship curve and the dynamic damping force, which was contrasted and compared with the experimental results of the squeeze type of damper. Finally, the squeeze type of MR damper developed in this research was proved to be valid as a semi-active control device, and also the evaluation of the two dynamic models showed they were working fine so that they were likely to be easily utilized to numerically predict the dynamic characteristics of any dampers with MR fluid as well as the squeeze type of MR damper.

Characteristics and Dynamic Modeling of MR Damper for Semi-active Vibration Control (준능동 진동 제어를 위한 MR 감쇠기의 동적 모델링을 통한 특성분석)

  • Heo, Gwang-Hee;Jeon, Seung-Gon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.6
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    • pp.61-69
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    • 2013
  • This research is aimed to evaluate characteristics and dynamic modeling of MR damper for semi-active vibration control. A MR damper of semi-active type was designed and made for the purpose of controlling the vibration of a real-size model structure. Usually a semi-active control system equipped with a MR damper requires a dynamic model which expresses numerical data about the damping capacity and dynamic characteristics generated by a MR damper. To fulfil the requirement, a Power model and a Bingham model were particularly employed among many dynamic models of MR damper. Those models being contrasted with other ones, a dynamic test was carried out on the developed MR damper. In the test, excitation frequencies were conditioned to be 0.15 Hz, 1.0 Hz, and 2.0 Hz, and three different currents were adopted for each frequency. From these test results, it was found that displacement affected control capacity of the MR damper. The test results led to the identification of model variables for each dynamic model, on the basis of which a force-speed relation curve and expected damping force were derived and contrasted to those of the developed MR damper. Therefore, it was proven that the MR damper designed and made in this research was effective as a semi-active controller, and also that displacement of 2mm at minimum was found to be secured for vibration control, through the test using various displacements.

Hysteresis Model of Damping Forces of MR Damper for a Passenger Car (승용차용 MR 댐퍼의 댐핑력 이력현상 모델)

  • 이순규;최승복
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.1
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    • pp.189-197
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    • 2001
  • This paper presents hysteresis models of damping forces of a magneto-rheological (MR) damper which is applicable to a middle-sized passenger vehicle. After manufacturing a cylindrical type of the MR damper, its field-dependant damping force and hysteresis behavior are experimentally evaluated. Three different models ; Bingham model, Bouc-Wen model and Polynomial model are provided to predict the hysteretic damping force. The damping force characteristics predicted from three different models are compared with the measured results under various excitation conditions.

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Bingham Charateristics of Electrorheological Fluid and Its Application to ER valve and ER Damper (전기유변유체의 빙햄특성과 밸브 및 댐퍼에의 응용)

  • 배종인
    • The Korean Journal of Rheology
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    • v.10 no.1
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    • pp.31-37
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    • 1998
  • 전기장이 인가되고 있는 유로를 유동하는 전기유변유체의 기본성질을 파악하기 위 한 실험 및 해석적 연구를 수행하여 빙햄유체로서의 유효성에 대해 알아보고 전기장과 유로 면 형상 및 진동유동으로 인한 영향에 대해 조사함으로써 ER밸브 및 ER대퍼로의 응용과 관련한 감쇄력 제어에 대해 검토하였다. 첫 번째 실험은 ER밸브의 높이가 2mm인 적극면이 평탄한것과 요철로 된 것을 사용하여 압력손실을 압력변환기로 측정함으로써 전기장 및 유 로형상에 대한 영향을 알아보았다. 압력손실 및 전단응력이 전기자세기와 함수관계를 가짐 을 알수 있었고 전기장세기와 유속의 변화시 손실계수에 의한 ER효과의 상이함이 확인되었 으며 레이놀즈수가 커지면 항복전단응력의 영향은 나타나지 않았다. 두 번째 실험은 실린더 를 정현파로 진동시켜 ER밸브에서 감쇠력제어가 가능한가를 알아보고 빙햄유체모델로 설계 된 ER댐퍼의 모델과 비교하였다. ER배르와 ER댐퍼의 수학적 모델을 시뮬레이션한 결과는 약간 벗어남이 보이기는 하나 실험결과와 일치하요 있다. 이것은 ER유체를 단순히 빙행유 체로 취급할수없으나 거시적으로는 빙햄유체로 취급할수 있음을 시사한다.

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Control Performance Investigation of MR Fluid Damper using Herschel-Bulkley Shear Model (Herschel-Bulkley 모델을 이용한 MR 댐퍼 승용차의 제어 성능 고찰)

  • 이덕영;황우석
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.323-328
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    • 2002
  • The control performance of a vehicle installed with an MR(magnetorheological) fluid-based damper is investigated on the basis of Herschel-Bulkley shear model. Generally, most of MR fluid damper has been analyzed based on a simple Bingham-plastic shear model. However, the Bingham-plastic shear model can not well describe the behavior of the damper on the condition of high velocity and high current field input. Therefore, in this study, the Herschel-Bulkley shear model in which the constant post-yield plastic viscosity in Bingham model is replaced with a power law model dependent on shear rate is used to assess control performance of a vehicle with MR fluid damper suspension system. This study deals with a two-degree-of-freedom suspension using the MR fluid damper for a quarter car model. The response for the bump input to identify the fastness of MR fluid damper embedded skyhook controller and requested magnetic field are investigated.

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