• Title/Summary/Keyword: high force damper

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Analysis of Isolation System in Distinct Multi-mechanism HIF Device (이종 복합 메카니즘 HIF 기구의 충격저감시스템 해석)

  • Choe Eui Jung;Kim Hyo-Jun
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.2
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    • pp.53-59
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    • 2005
  • In this study, the isolation system for multi-mechanism HIF (high impulsive force) device has been investigated. For this purpose, parameter optimization process has been performed based on the simplified isolation system model under constraints of moving displacement and transmitted force. The design parameters for multi-mechanism HIF device have been derived with respect to HIF system I and HIF system II, respectively. In order to implement the dynamic absorbing system, the dual stage hydro-pneumatic damper and magnetorheological damper with semi-active control scheme are considered. Finally, the performance of the designed prototype isolation system has been evaluated by experimental works under actual operating conditions.

A Study on the control force of HMD for vibration control of the tall building structure (고층 구조물의 진동제어를 위한 복합형 질량댐퍼의 제어력 설계에 관한 연구)

  • Park, Jin-Il;Park, Hae-Dong;Choi, Hyun;Kim, Doo-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.276-281
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    • 2000
  • As the construction of the high-rise building increases worldwide, the effort has been exerted to improve the safety and serviceability if the structure against various types of external dynamic loads such as wind load, seismic load, etc. The mass damper, defined as dynamic absorber in mechanical engineering is known one of the effective methods to control the vibration of flexible large structures. The hybrid mass damper, HMD is known as the most appropriate type of the mass dampers. In this paper, the control force was designed for HMD by numerical simulations and the performance of HMD to control the flexible vibration of the steel tower induced by sinusoidal force excitation was evaluated, also TMD was designed for a 1-DOF lumped mass model.

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Performance Evaluation of Multi-Friction Dampers for Seismic Retrofitting of Structures (구조물 내진보강을 위한 다중 마찰댐퍼의 성능 평가)

  • Kim, Sung-Bae;Kwon, Hyung-O;Lee, Jong-Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.6
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    • pp.54-63
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    • 2022
  • This paper is a study on the friction damper, which is one of the seismic reinforcement devices for structures. This study developed a damper by replacing the internal friction material with ultra high molecular weight polyethylene (UHMWPE), a type of composite material. In addition, this study applied a multi-friction method in which the internal structure where frictional force is generated is laminated in several layers. To verify the performance of the developed multi-friction damper, this study performed a characteristic analysis test for the basic physical properties, wear characteristics, and disc springs of the material. As a result of the wear test, the mass reduction rate of UHMWPE was 0.003%, which showed the best performance among the friction materials based on composite materials. Regarding the disc spring, this study secured the design basic data from the finite element analysis and experimental test results. Moreover, to confirm the quality stability of the developed multi-friction damper, this study performed an seismic load test on the damping device and the friction force change according to the torque value. The quality performance test result showed a linear frictional force change according to the torque value adjustment. As a result of the seismic load test, the allowable error of the friction damper was less than 15%, which is the standard required by the design standards, so it satisfies the requirements for seismic reinforcement devices.

A study on the Application of Electromagnetic Type HMD for Vibration Control of Structure (구조물 진동제어를 위한 전자석구동 HMD의 응용에 관한 연구)

  • Choi, Hyun;Jeoung, Jeoung-Kyo;Kim, Doo-Hoon;Lee, Sang-Jo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.280-285
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    • 2000
  • With recent development of technology of high stiffness material and the structural design, the construction of high rise structures such as tall building, tower has increased. The more flexible and slender structure is vulnerable to the internal and external dynamic loads induced by earthquake, wind and traffic load. There have been great effort and many researches to minimize the influence of dynamic loads on the structure. The traditional and stable method, the application of the passive damper, is not able to comply with various dynamic loads, while the mass damper which active control technology is integrated can effectively comply with load types. Therefore, the application of active control of huge structures with AMD(Active mass damper) or HMD(Hybrid Mass damper) is increasing. Up to now, most of actuators are servomotor and hydraulic actuator. But it is known that the electromagnetic actuator applies non contacting control force, which makes the control system easier with no characteristic change depending on time. In this paper, Hybrid mass damper with electromagnetic actuator was designed and applied to building scaled structure. The performance of designed HMD tested by shake table test is included.

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Hybrid Control of Aircraft Landing Gear using Magnetorheological Damper (MR댐퍼를 적용한 항공기 착륙장치의 하이브리드 제어기법 연구)

  • Tak, Jun Mo;Viet, Luong Quoc;Hwang, Jai-Hyuk
    • Journal of Aerospace System Engineering
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    • v.12 no.1
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    • pp.1-9
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    • 2018
  • In this study, a hybrid control method that adjusts for the existing force control technique has been presented for consideration. The proposed hybrid control technique does away with the chattering phenomenon occurring in existing force control technique and provides high shock absorption efficiency. In order to design the controller for the landing gear with MR damper, the equation of motion of the landing gear was derived. The hybrid controller was designed after constructing a simulation model using Recur-Dyne, multi-body dynamic analysis software. The hybrid controller can reduce the maximum strut force and displacement based on the skyhook controller, and is able to get the high efficiency by making it work for the additional force control technique. In addition, an effective switching control technique and input shaping technique was applied to prevent the chattering in the drop simulation. Finally, the performance of the landing characteristics was evaluated throughout the various drop simulations.

A Parameter Study of Lateral Damper on Hunting Stability of Maglev Vehicle (자기부상열차의 주행안정성 해석에 의한 횡 댐퍼 파라미터 연구)

  • Han, Jong-Boo;Kim, Ki-Jung;Kim, Chang-Hyun;Han, Hyung-Suk
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.75-80
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    • 2011
  • In the area of wheel on rail vehicle, hunting stability which is generated by lateral motion is one of important characteristics for running safety. It might cause not only oscillation of vehicle but also derailment in an unstable area of the high speed. A Maglev vehicle is usually controlled the voltage to maintain the air gap between electromagnet and track. However, in Maglev system, an occurrence possibility of hunting motion could be high, because Maglev vehicle is not controlled directly lateral force between electromagnet and track in the curved guideway. In this paper, running safety is evaluated when Maglev vehicle run on guideway at high speed according to installment of damper between maglev vehicles and bogies, and to analyze the effect of it. Also, the parametric study is carried out for selecting effective lateral damper properties through the simulation. To accurately predict the running safety, 3d multibody dynamics models which are included air spring, guideway conditions and irregularities profile are used. With the results acquired, suggestions were made whether to adopt the damper and how to optimize the damping characteristics.

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Multi-dimensional seismic response control of offshore platform structures with viscoelastic dampers (I-Theoretical analysis)

  • He, Xiao-Yu;Li, Hong-Nan;Zhang, Jun
    • Structural Monitoring and Maintenance
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    • v.3 no.2
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    • pp.157-174
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    • 2016
  • Based on classical viscoelastic damper, a brand-new damper is designed by the change of simple construction to implement vibration control for both translational vibration and rotational vibration simultaneously. Theoretic analysis has been carried out on the restoring force model and the control parameters. Two improved models are presented to obtain high simulation precision. The influence of the size, shape of the viscoelastic material, the ambient temperature and the response frequency on the vibration control effect is analyzed. The numerical results show that the new type viscoelastic damper is capable of mitigating the multi-dimensional seismic response of offshore platform and the response control effect has complicated relations with aforementioned related factors.

Application of MR damper for Vibration Control of Adjacent Buildings (인접건축물의 진동제어를 위한 MR감쇠기의 적용)

  • Kim, Gee-Cheol;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.12 no.4
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    • pp.99-108
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    • 2012
  • In recently, sky-bridge are often applied to high-rised adjacent buildings for pedestrian bridge. the seisnic response control of adjacent buildings have been studied and magneto-rheological(MR) fluid dampers have been applied to seismic response control. In this study, vibration control effect of the MR damper connected adjacent buildings has been investigated. Adjacent building structures with different natural frequencies were used as example structures. Two typed of control methods, displacement based or velocity based, are applied to determinate control force of MR damper. In this numerical analysis, it has been shown that displacement-based control algorithm is more effective than velocity-based control algorithm for seismic response control of adjacent buildings. And, when displacement-based control method is applied to control of adjacent buildings, the control of building occurred large displacement is more efficient in reducing the seismic response.

Squeeze Film Damper for High Speed Stable Operation (고속 안정 운전을 위한 스퀴즈 필름 댐퍼)

  • Yoon, Seok-Cheol
    • Journal of the Korean Society of Safety
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    • v.19 no.1
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    • pp.131-136
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    • 2004
  • Four new types of squeeze film dampers have been experimentally investigated to develop a practical and effective damper for flexible rotors. The cylindrical bush damper was selected as the best one among them and applied in a test rotor supported on ball bearings. A stable running of the rotor exceeding the critical speed was observed.