• Title, Summary, Keyword: Damper

Search Result 2,141, Processing Time 0.039 seconds

Research for the Pulsating Pressure Characteristics by a Damper and an Accumulator in the High Frequency Hydraulic System (고주파 유압시스템에서 감치장치와 축압기에 의한 맥동 충격파 감쇄특성에 대한 연구)

  • Kim, Yang-Soo;Kim, Jae-Soo;Rho, Hyung-Woon
    • 유체기계공업학회:학술대회논문집
    • /
    • /
    • pp.641-647
    • /
    • 2004
  • Characteristics of the high frequency pulsatile flow have been investigated experimentally to understand the flow phenomena in the hydraulic system. The accumulator in high frequency hydraulic system but that is not effective all frequency zone. Therefore, a hydraulic damper used with accumulator is suggested to reduce the high frequency pulsatile where the accumulator is not effective. The pulsating pressure obtained by Pressure measurement system are analyzed to power spectral density distribution. According to the variations of pump input pressure and actuator acceleration frequency, the pressure is measured with or without an accumulator or pulsatile damper The amplitude of pressure with damper is very lower than those without accumulator or damper due to absorbing function of damper. As the frequency of actuator acceleration is increased, the effect of damper becomes very important to decrease the amplitude of pulsatile Pressure waveform with high frequencies.

  • PDF

Study of the Non-linearity of Cable Damper to Enhance Damping Performance of Stay Cable (사장교 케이블의 감쇠성능 향상을 위한 댐퍼의 비선형성 연구)

  • Seo, Ju-Won;Koh, Hyun-Moo
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.17 no.9
    • /
    • pp.785-796
    • /
    • 2007
  • This study offers a design procedure of optimum cable damper for multi-mode vibration control with nonlinear damper and also investigates the relation between mode and amplitude dependency. The proposed multi-mode damping index, which is defined as a potential energy loss ratio of cable vibration, is a main component of optimization problem of optimum nonlinear damper. In order to include the amplitude dependency of nonlinear damper, three types of multi-mode patterns such as ambient vibration, support excitation and rain-wind induced vibration are assumed. The optimum damper exponent depends on amplitude patterns. In case of ambient vibration, optimum factor is less than 0.5 and in case of support excitation or rain-wind induced vibration it is between 0.5 and 1.0.

Study of the non-linearity of cable damper to enhance damping performance of stay cable (사장교 케이블의 감쇠성능 향상을 위한 댐퍼의 비선형성 연구)

  • Seo, Ju-Won;Koh, Hyun-Moo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.147-156
    • /
    • 2007
  • This study offers a design procedure of optimum cable damper for multi-mode vibration control with nonlinear damper and also investigate the relation between mode and amplitude dependency. The proposed multi-mode damping index, which is defined as a energy loss ratio of cable potential, is a main component of optimization problem of optimum nonlinear damper. In order to include the amplitude dependency of nonlinear damper, it is assumed to exist three kinds of multi-mode patterns such as ambient vibration, support excitation and rain-win induced vibration. The optimum damper exponent depends on amplitude patterns. In case of ambient vibration, optimum factor is less than 0.5. In case of support excitation or rain-wind induced vibration is between 0.5 and 1.0. In this study, the effects of cable sag and inclination angle are included in the asymptotic design equation of damped cable structures.

  • PDF

A Experiment of the damping effect for Electromagnetic Damper using DC Motor and Ballscrew (DC Motor와 Ballscrew를 이용한 Electromagnetic Damper Damping 효과 실험)

  • Kang, Jeong-Ho;Lee, Hac-Choel;Jeong, Young-Suk
    • Proceedings of the KIPE Conference
    • /
    • /
    • pp.124-126
    • /
    • 2008
  • In this Paper, the modeling of the electromagnetic damper for automobile suspension is presented and the validation of the model is demonstrated by experiments. An electromagnetic damper, composed of a rotary DC motor, and a ball screw and nut. The damper then operates as a linear electric actuator. The damper then operate as a linear electric actuator. The results indicate the proposed system is feasible and it is proved that the electromagnetic damper has better than oil damper of passive control system.

  • PDF

Development of Performance Analysis Program for a Hydraulic Shimmy Damper of Steering System (조향계 유압 시미댐퍼의 성능해석 프로그램 개발)

  • 이재천;정용승;김진홍
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.12 no.1
    • /
    • pp.174-183
    • /
    • 2004
  • A program to analyze the performance characteristics of a hydraulic shimmy damper for automotive steering system was developed in this study. Dimensionless mathematical equations of the dynamics of shimmy damper for forward and reverse fluid flows were derived respectively and incorporated into the Simulink models. The program was validated by comparing the results of simulation and experiments for various frequencies of upstream ripple pressures into the damper. Low-pass filter characteristics of the shimmy damper at reverse flow was demonstrated which means that the shimmy damper could alleviate the high speed ripple pressures induced by the unbalance oscillation of tire in vehicle driving. The parameter sensitivity analysis was also conducted to identify the dominant parameters for the damper performance.

A Study on the Variable Damper System for Vehicle Driveline (차량구동계용 가변 댐퍼시스템에 관한 연구)

  • Park Dong-Hoon;Choi Myung-Jin
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.14 no.9
    • /
    • pp.837-845
    • /
    • 2004
  • A variable friction damper for vehicle driveline has been proposed. This new torsional damper system uses a solenoid as an actuator to vary friction force of the damper. To verify the idea of using a solenoid in a variable damper system, the test fixture and the dampers are made and tested. Also, to find out the range of damper friction forces that influence the vehicle driveline vibration, a mathematical model of the driveline had been developed and simulated. Test and simulation results show that, within electric current used in the vehicle electric system, the solenoid can develop enough friction force that will surpass resonance in the driveline of 1.5 L Gasoline engine vehicle during acceleration.

Design of MR damper with multi_stage core (다중 자기 코일 작동기를 사용한 MR damper의 설계해석)

  • Lee, Gyu-Seop;Yoo, Won-Hee;Ryu, Bong-Jo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.525-528
    • /
    • 2008
  • The dynamic range of MR damper is the most important characteristics for the usage of semi-active control system. The damping force can be increased by simply decresing the orifice gap in the traditional oil damper, but it deteriorate the dynamic range in MR damper. In this paper, the multi-stage electro-magnetic core is suggested to maintain the performance of MR damper with a large damping force. The MR damper with 3 stage core is designed and manufactured for testing and analysis.

  • PDF

Analysis of Magnetic Field of Superconducting Winding According to the Changed Damper Thickness and Material (댐퍼의 두께와 재질 변화에 따른 초전도 선재에 미치는 자장특성 분석)

  • Jeong, Jae-Sik;Lee, Sang-Ho;Hong, Jung-Pyo;Jo, Young-Sik
    • Progress in Superconductivity and Cryogenics
    • /
    • v.14 no.3
    • /
    • pp.5-8
    • /
    • 2012
  • Superconducting windings of synchronous machine have to be operated in below the critical temperature, critical current density and critical magnetic field. If one of these characteristics does not satisfied, then the quench occurred in superconducting winding. Especially the armature current dramatically increased as the superconducting generator is short-circuited at the rated load condition and magnetic field in field winding increased due to the armature current. Therefore, damper is required to reduce the magnetic field of field winding which increases reliability of the superconducting generator. Damper dimension can be decided by time constant[1-2]. In this paper the basic model is high-power and low-speed superconducting generator. Damper time constant was calculated from the changed damper thickness and material. Magnetic flux of field coil at the basic model and changed damper time constant model is analyzed.

Design of a Light Weight Watertight Damper for Offshore Rigs (해양시추선용 경량수밀댐퍼 설계)

  • HAN, Seung-Hun;JANG, Ji-Seong;JI, Sang-Won
    • Journal of Fisheries and Marine Sciences Education
    • /
    • v.28 no.5
    • /
    • pp.1470-1477
    • /
    • 2016
  • This study has designed and evaluated the safety of watertight damper for Offshore Rigs. The watertight damper is an improved design for conventional DN 350 butterfly valve. Numerical analysis has been performed to investigate the safety factor and seat leakage of the designed 3-type disk dampers. The structure analysis results present the deformations, the equivalent stresses and the safety factor. It was confirmed that the designed disk, rib-disk and streamlined disk of watertight damper are safe enough in maximum operating pressure of 0.98MPa. The results show that the disk damper had the smallest maximum deformations and stress among 3-type disk dampers and the safety factor was 4.3. Therefore it is confirmed that the disk damper has the most excellent strength. Also linear static structural analysis was individually conducted for disk and body. The results show that the maximum disk deformation was larger than the body deformation, Therefore the disk damper is causes no seat leakage.

The controllable fluid dash pot damper performance

  • Samali, Bijan;Widjaja, Joko;Reizes, John
    • Smart Structures and Systems
    • /
    • v.2 no.3
    • /
    • pp.209-224
    • /
    • 2006
  • The use of smart dampers to optimally control the response of structures is on the increase. To maximize the potential use of such damper systems, their accurate modeling and assessment of their performance is of vital interest. In this study, the performance of a controllable fluid dashpot damper, in terms of damper forces, damper dynamic range and damping force hysteretic loops, respectively, is studied mathematically. The study employs a damper Bingham-Maxwell (BingMax) model whose mathematical formulation is developed using a Fourier series technique. The technique treats this one-dimensional Navier-Stokes's momentum equation as a linear superposition of initial-boundary value problems (IBVPs): boundary conditions, viscous term, constant Direct Current (DC) induced fluid plug and fluid inertial term. To hold the formulation applicable, the DC current level to the damper is supplied as discrete constants. The formulation and subsequent simulation are validated with experimental results of a commercially available magneto rheological (MR) dashpot damper (Lord model No's RD-1005-3) subjected to a sinusoidal stroke motion using a 'SCHENK' material testing machine in the Materials Laboratory at the University of Technology, Sydney.