• 동력기계공학회지
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• 제1권1호
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• pp.98-105
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• 1997

In general, crankshafts which are used in internal combustion reciprocating engines are subjects to high torsional vibration. Therefore, a damper is often used to minimize the torsional vibration in reciprocating engines. In this paper, in order to investigate damping performance of viscous damper, the real effective viscosity and complex damping coefficient of silicone oil, and the effective inertia moment of inertia ring are calculated considering the relative motion between damper casing and inertia ring. Based on these results multi-cylinder shaft is modeled into equivalent 2-degree of freedom system and optimum condition is estimated by calculating the amplification factor of viscous damper. Also the test damper was manufactured according to the result of theoretical investigation, the performance and durability was ascertained through experimental examination.

• 한국지진공학회논문집
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• 제26권4호
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• pp.149-156
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• 2022

Magneto-Rheological Fluid (MRF) is a functional fluid in which flow characteristics change into magnetic force due to its magnetic particles. When the semi-active control device does not use MRF for a long time, precipitation of magnetic particles and abnormal control force occur. Thus, Electro Magneto-Rheological Fluid (EMRF), which improves the precipitation of magnetic particles for MRF and exhibits existing control performance, was developed in this study. First, the optimal mix proportion ratio was selected by conducting a precipitation experiment and a controlled force test by varying the content of grease based on the existing MRF components. Also, EMRF was applied to the shear-type damper to evaluate the control performance when applied to the control device. The cylinder-type damper was developed to apply to the structure, and control performance evaluation was conducted. The result confirmed that the precipitation of the magnetic particles was improved, while the damper using EMRF exhibited excellent control performance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.344-349
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• 2012

This paper presents a new small-sized damper featuring magneto-rheological (MR) fluid which can be applied to vibration control system. The proposed MR damper consists of cylinder, piston, a couple of bearings, oil-seals and magnetic circuit which has two coils. In this damper, approximately 5cc of MR fluid is used. The damping force of the MR damper is designed to be followed by linear shear-mode Bingham-plastic model. In order to verify the performance of the MR damper, an experimental apparatus is established. In the experimental test, the damping force of the MR damper is measured with respect to time, displacement and velocity. In addition, the time response of MR damper is measured when 1A of step current is applied. Finally, The proposed small MR damper is applied to vibration control. In this process, a simple 1-DOF system is modeled and controlled using PID controller.

• 한국소음진동공학회논문집
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• 제22권11호
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• pp.1121-1127
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• 2012

This paper presents a new small-sized damper featuring magneto-rheological(MR) fluid which can be applied to vibration control system. The proposed MR damper consists of cylinder, piston, a couple of bearings, oil-seals and magnetic circuit which has two coils. In this damper, approximately 5cc of MR fluid is used. The damping force of the MR damper is designed to be followed by linear shear-mode Bingham-plastic model. In order to verify the performance of the MR damper, an experimental apparatus is established. In the experimental test, the damping force of the MR damper is measured with respect to time, displacement and velocity. In addition, the time response of MR damper is measured when 1A of step current is applied. Finally, the proposed small MR damper is applied to vibration control. In this process, a simple 1-DOF system is modeled and controlled using PID controller.

• 한국지진공학회논문집
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• 제23권4호
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• pp.211-219
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• 2019

In this study, SMG(Smart Material with Grease) was developed, which was improved the precipitation minute particle in grease during long term standstill. Also, small-sized cylinder damper equipped with an electromagnet in a piston was developed for using a performance evaluation of the damper with SMG and the dynamic load test, and damping force using Power model and Bingham model was derived in order to compare to the result of that of the damper. The data obtained from the dynamic load test were analyzed and plotted, and then a dynamic range was calculated to evaluate the usability of the damper with SMG. The performance of the damper with SMG was compared to the damping forse derived from the Power and Bingham model. The result of this evaluation shown that the usability of SMG damper was demonstrated by this test as a semi-active controlling equipment of small-sized damper.

• 한국기계가공학회지
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• 제5권3호
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• pp.5-10
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• 2006

The objective of this paper is to investigate the Intelligence control characteristics of a digital damper. This paper deals with a two-degree-of-freedom suspension using the damper with ER fluid for a quarter vehicle system. The control law for semi-active suspensions modeled in this study is developed using passive and ANFIS control method. Computer simulation results show that the semi-active suspension with ER damper has good performances of ride quality.

• 대한기계학회논문집A
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• 제25권4호
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• pp.685-694
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• 2001

In this study, a transfemoral prosthesis system of which both stance phase and swing phase are controllable has been developed for the recovery of the biomechanical function of the amputated leg. It consists of a 5 bar link mechanism, a hydraulic-rubber knee damper for stance phase control and a pneumatic cylinder controlled via a microprocessor for stance phase control. The mechanical characteristics of the knee damper which absorbs the impact energy generated at the heel contact were investigated. The characteristics of the pneumatic cylinder essential for the speed adaptation of the prosthesis during swing phase were also studied for its mechanical characteristics. The prosthesis was subject to the clinical tests, and the gait characteristics obtained were very close to those of normal subjects. The stance and swing controlled prosthesis that were developed in this study showed good stability during the stance phase and showed good controllability during the swing phase.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.504-509
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• 2000

In this study, a transfemoral prosthesis system of which stance phase and swing phase are controlled during walking has been developed for the recovery of the biomechanical function of the amputated leg. It consists of a 5 bar link mechanism, a hydraulic-rubber knee damper for stance phase control and a pneumatic cylinder controlled via a microprocessor for stance phase control. The mechanical characteristics and behaviour of the knee damper which absorbs the impact energy generated at the heel contact was investigated. The characteristics of the pneumatic cylinder essential for the speed adaptation of the prosthesis during swing phase was also studied for its mechanical characteristics. The prosthesis was subject to the clinical test ant the gait characteristics obtained were very close to those of normal. The stance and swing controlled prosthesis that were developed in this study showed good stability during the stance phase and showed good controllability during the swing phase.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.826-830
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• 1996

The pneumaic systems are widely applied to chemical factory of fire dangry and factory automation. by using compressed air, it is difficult to dynamics action analysis that the pneumatics system acts to nonlinear motion through orifices and valve flow. This paper was studied to a nonlinear chararistics of pneumaic spring, damper and absorber of pneumaic cushion cylinder.

• 한국항공우주학회지
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• 제35권12호
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• pp.1089-1094
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• 2007

연구에서는 코일 스프링 및 작동유체가 없는 새로운 감쇠기의 개념을 소개한다. 이 감쇠기는 영구자석과 전도체 실린더로 구성된다. 극성이 반대인 자석은 반발력을 발생시키고, 이는 코일 스프링과 같은 역할을 한다. 영구자석과 전도체 실린더 사이의 상대운동은 기전력을 발생시키는 와전류를 생성하고, 이로 인해 감쇠 유체를 대신할 수 있는 감쇠력을 만든다. 이러한 감쇠를 와전류 감쇠기라고 한다. 본 연구에서 제안된 와전류 감쇠기의 중요한 장점은 감쇠 유체 및 어떠한 외부의 전력도 필요로 하지 않고, 비접촉식이며, 온도에도 민감하지 않다. 본 연구에서는 제안된 와전류 감쇠기를 제작하고 실험을 통하여 감쇠기의 동적 특성을 조사하였다. 본 연구의 결과는 제안된 와전류 감쇠기가 우수한 감쇠 성능을 가짐을 보였다.