• Title, Summary, Keyword: Damper characteristics

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Analysis of Continuously Variable Damper Characteristics for Semi-Active Suspension Systems (반능동형 현가시스템을 위한 연속가변댐퍼의 특성 해석)

  • 허승진;박기홍
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.7
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    • pp.128-137
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    • 2003
  • Continuously variable damper can yield diverse damping forces for a single damping velocity. It is widely used in the semi-active suspension system since, with right control logics, it can enhance ride comfort compared to the passive damper while not degrading driving safety. A key to the successful design of the continuously variable damper is the knowledge of its complex and nonlinear characteristics. In this paper, research has been done for analyzing characteristics of the continuously variable damper. Various damper components have been investigated and their effects upon the force-velocity characteristics of the damper have been examined. The effects of the damper characteristics change upon ride comfort and driving safety have also been investigated by numerical simulations.

A Study on the Dynamic Characteristics of Free-Friction Stroke Damper by Finite Element Method (유한요소법을 이용한 Free-Friction Stroke 댐퍼의 동특성 해석)

  • Ku, Hi-Chun;Lee, Jae-Wook;Yoo, Wan-Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.12
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    • pp.1417-1426
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    • 2009
  • Various types of damper are usually applied to reduce noise and vibration for mechanical systems. Especially, for washing machines, the free-friction stroke damper is installed. The behavior of the free-friction stroke damper has nonlinear characteristics such as hysteresis and viscoelastic properties because of its foam material. First of all, the dynamic experiments were carried out by using a MTS machine to find characteristics of the free-friction stroke damper. And the simulation model of the free-friction stroke damper and characteristics of a foam material were evaluated by using optimization technique. To make a good simulation model which can show the dynamic characteristics, it is important to understand the working mechanism of the damper. The Finite Element Method (FEM) technique can help us instinctively understand the damping phenomenon under operating conditions, because we can observe the condition of damper at every step in the simulation by using it. Also, by changing factors, we can comprehend the variation of characteristics of damper. So, in this paper, a study on the dynamic characteristics of free-friction stroke damper by FEM is focused on. Finally, the possibility which physical experiments can be replaced into simulations is shown.

A Study on the Characteristics of an Amplitude Proportional Friction Damper (변위비례식 마찰댐퍼의 특성에 관한 연구)

  • 박동훈;최명진
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.717-720
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    • 2002
  • An Amplitude Proportional Friction Damper (APFD) system is considered in order to improve the stick-slip characteristics of Coulomb friction damper. The frictional force is proportional to the amplitude in APFD system and the system is non-linear as is Coulomb damper system. The free vibration analysis on an 1-DOF system has conducted to demonstrate the characteristics of the APFD system and the results show that the APFD system has similar damping characteristics to the viscous damper system. It is concluded that the APFD system may become a cost effective substitution for the viscous damper and it also has certain advantages over Coulomb damper system since the APFD system can be designed to work with no stick-slip.

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Impulse Response Analysis of an Amplitude Proportional Friction Damper System (변위비례식 마찰댐퍼 시스템의 임펄스 가진 응답해석)

  • 최명진;박동훈
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.5
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    • pp.377-384
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    • 2004
  • An Amplitude Proportional Friction Damper (APFD), in which the friction force is proportional to the system displacement, has been introduced and mathematically modeled. To understand the damping characteristics of APFD, analytical solutions for the impulse response has been derivedand compared to the viscous damper. It is found that APFD system has very similar damping characteristics to viscous damper even though it is a friction damper. APFD may be used as a cost-effective substitution for the viscous damper and could also be used to improve the simple friction or Coulomb dampersince APFD works with no stick-slip and always returns to original position when external disturbance is disappeared.

An Experimental Study on Performance Evaluation of Hysteretic Steel Slit Damper (슬릿형 강재이력 감쇠장치의 성능평가를 위한 실험연구)

  • Choi, Ki-Sun;Lee, Hyun-Jee;Kim, Min-Sun;You, Young-Chan
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.1
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    • pp.33-39
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    • 2018
  • This study performed experimental validation of the hysteretic steel slit damper's basic and dependent characteristics, which should be considered for the design. The basic characteristic of the steel slit damper is used for determining design properties of non-linear analysis, such as yielding strength, yielding displacement, elastic stiffness and post-yielding stiffness. In order to evaluate dependent characteristics of the hysteretic steel slit damper, repeated deformation capacity with respect to the displacement, velocity and aspect ratio of the damper was evaluated. In this study, steel slit damper, which is widely used in Korea, was considered. The slit dampers with 55kN and 240kN of yielding strength were produced and tested. It was concluded that the slit damper's hysteresis behavior was affected by the dependent characteristics: displacement, velocity and aspect ratio. In other words, the steel slit damper's behavior was stable within limit displacement, and aspect ratio of the strut affected repeated deformation capacity of the damper subjected to large deformation. In addition, it was observed that the repeated deformation capacity abruptly decreased at the high speed range (${\geq}60mm/sec$). Furthermore, the experimental results were evaluated with the criterion of the damping device specified in ASCE7-10.

Mechanical Characteristics Analysis of Coil Spring & Viscous Damper System (Coil Spring & Viscose Damper System의 동적거동특성분석)

  • Kim, Min-Kyu;Choun, Young-Sun
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.471-478
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    • 2006
  • This paper presents the results of experimental studies of the mechanical characteristics of the Coil Spring and Viscous Damper system. The Coil Spring and Viscous Damper systems were selected for the isolation of Emergency Diesel Generator (EDG) which is located in Nuclear Power Plant (NPP). The Coil Spring and Viscous Damper systems were developed for, the operating vibration isolation and seismic isolation for scaled Model EDG System. The damping properties of the viscous damper changes as the variation of velocity. As a results, nonlinear damping characteristics of viscous damper system were evaluated.

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Vibration Analysis of an Amplitude Proportional Friction Damper System (변위비례식 마찰댐퍼 시스템의 진동해석)

  • 박동훈;최명진
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.5
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    • pp.171-179
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    • 2003
  • An Amplitude Proportional Friction Damper (APFD) is considered in order to improve the characteristics of Coulomb friction damper. The frictional force is proportional to the amplitude in APFD system and the system is non-linear as is Coulomb damper system. A free vibration analysis on the 1-DOF system has made to demonstrate the characteristics of the APFD system. The results show that APFD system has similar damping characteristics to the viscous damper. Also, the solution for the response of a base-excited system with APFD is developed through the application of a Fourier series to represent the frictional force of APFD. It is assumed that no stick-slips occur during any portion of the steady-state oscillation.

Nonlinear Dynamic Characteristics of an Automobile Damper (자동차용 댐퍼의 비선형 동특성)

  • Cho, Sung-Jin;Jeon, Kwang-Ki;Choi, Sung-Jin;Choi, Gyoo-Jae;Choi, Yeon-Sun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.873-876
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    • 2005
  • The nonlinear characteristics of a damper is directly related to the car behavior and performance, both for handling and comfort. So considering the nonlinear characteristics of a damper such as hysteresis is important to analyze the dynamic characteristics of a car suspension. In this study, a mathematical nonlinear dynamic damper model based on experimental data is devised to estimate the nonlinear parameters of a NEW EF-SONATA damper using the least square method. The devised nonlinear dynamic damper model is used to analyze the reaction force of a NEW EF-SONATA suspension using ADAMS. The simulation results are good agreement with the experimental data than those of the linear model.

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Damping Force Characteristics of MR Damper with Additional Flow Path (부가적인 유로가 있는 MR 댐퍼의 감쇠력 특성)

  • Sohn, Jung Woo;Oh, Jong-Seok;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.25 no.6
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    • pp.426-431
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    • 2015
  • In this work, a new type of MR damper with additional flow path in piston is proposed and damping force characteristics are numerically evaluated. Flow-mode type MR damper is considered and mathematical model is established based on Bingham rheological model of MR fluid to obtain accurate prediction of damping force characteristics. Damping force of the proposed MR damper are calculated with respect to piston velocity and input current. In addition, investigation on damping force characteristics is carried out according to number of additional flow path and excellence of the proposed MR damper is demonstrated.

A Review of Optimum Damper Characteristics of Dual Mass Flywheel (듀얼매스 플라이휠의 최적 댐퍼 특성에 대한 고찰)

  • 박동훈;최명진
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.986-990
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    • 2002
  • Dual Mass Flywheel(DMF) is used in order to improve the vibration characteristics of drivetrain of manual transmission vehicles. Regardless of its complexity and high cost, application of DMF is keep increasing due to a trend of using Diesel engines in passenger cars and light weight design of drivetrains. Modeling and analysis of DMF is rather simple, but finding out optimum parameters of damper may not be easy. Furthermore, its realization in DMF has some limitations due to DMF's structure and its structure dependent damping characteristics. Requirements on spring-damper characteristics of DMF has been reviewed and investigations on structures and damping characteristics of currently Produced DMFs have been made in this paper. Also, ideal spring and damper characteristics has been proposed based on such investigations.

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