• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.990-993
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• 2008

Vibration/shock affects biggest taking a train subtraction of vehicle and durability decline. Therefore, absorber is used for vibration/shock isolation and various qualities of the material and design are applied to isolation. This paper proposes vibration/shock absorber that applies 'Disc'spring. Through comparison with 'Disc' spring that has nonlinearity and coil spring that is having linearity, see effect that nonlinearity of isolation gets in vibration/shock isolation. Coil spring and 'Disc' spring are non-linear numerical analysis and simulation through theory for this, get and investigate comparison result through an experiment finally. Expressed and formulated shock through 'Runge-Kutta' method/impact response to nonlinear-vibration-equation of 1 degree of freedom for numerical analysis. Double half sine pulse of excitation used and analyzed result through spectrum response analysis here. Response of disc spring is compared to response of coil spring by changing ho/t ratio with computer simulation and the usage of disc spring is increased through analysis of effect of design factors. The purpose of this paper is that the shock response of disc spring is calculated through numerical simulation and to design the optimal absorber under the limited condition. And then, the isolation effect was analyzed through the shock test.

• 대한기계학회논문집B
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• 제35권10호
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• pp.1047-1052
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• 2011

디젤엔진은 기동 정지 시간이 빠르고 내구성과 신뢰성이 높아 대용량 발전소의 비상 발전기뿐 아니라 제한된 도서지역의 발전용으로 유용하게 사용되고 있다. 그러나 디젤엔진에 고진동이 발생될 경우 엔진 구조물 자체의 손상뿐 아니라 운전 신뢰성을 저해하는 요소가 될 수 있다. 본 논문은 고진동으로 인하여 수년간 출력을 감발하여 운전되었던 대형 발전용 디젤엔진의 고 진동 원인을 분석하기 위하여 수행한 시험 및 해석과 대책 수립에 대하여 기술하였다. 진동의 원인으로는 발전기 축의 비틀림 가진으로 인한 엔진 구조물의 공진으로 분석되었으며 수립된 대책을 시뮬레이션 후 실제 발전소에 적용하여 양호한 진동 저감 결과를 얻을 수 있었다.

• 한국산학기술학회논문지
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• 제20권10호
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• pp.296-302
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• 2019

본 연구에서는 이수순환시스템 핵심 장비 중의 하나인 셰일 셰이커 시작품의 핵심 부품을 선정하여 기초 내구성 평가를 수행하고 분석하였다. 기초 내구성 평가의 경우, 바이브레이터 모터(이하, 모터)가 장시간 운전에 따른 모터 베어링의 수명과 모터로 부터 유발된 진동에 의한 지지 스프링의 강성저하가 장비의 내구성에 적지 않은 영향을 미칠 수 있을 것이란 가정을 두었다. 모터 연속운전에 있어, 전 초기 진동 가속도의 P-P 수준은 0.72 g 수준 이었으나 운전 100 시간 경과 후, 진동 가속도의 P-P 수준은 1.26 g로 급격히 상승함을 볼 수 있었으며, 진동 상승의 원인분석을 위해 볼 결함주파수 분석기법을 통해 베어링 결함을 추정할 수 있었다. 또한, 셰일 셰이커의 가진 조건을 피로내구시험에 적용하여 시험 2,000 시간 경과 시, 스프링의 강성이 약 3.78 % 감소함을 확인 할 수 있었다. 향후 본 연구는 스프링 강성의 저하가 셰일 셰이커의 입자제거 효율이 미치는 영향 분석과 그에 따른 고장수명에 예측에 관한 후속 연구를 수행 할 예정이다.

• 한국산업융합학회 논문집
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• 제25권6_3호
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• pp.1239-1246
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• 2022

This paper introduces the effect of grease on the degradation characteristics of bearings used as key components of packaging equipment and automation systems. Bearings parts are installed to fix and support the rotating body of the system, and performance degradation of the bearings has a great effect on the life of the system too. When bearings are used in various devices and systems, the grease is applied to reduce friction and improve fatigue life. Determining the type of lubricant (grease) is important because it has a great influence on the operating environment and lifespan and ensures long lifespan of systems and facilities. However, studies that simultaneously compared and analyzed the change in mechanical degradation characteristics and the comparison of chemical degradation characteristics according to grease types under actual operating conditions are insufficient. In this paper, three types of small harmonic drive, high-load reducer, and low-load reducer grease used in power transmission joint modules are experimentally selected and finally injected into ball bearings with a load (19,500N) to improve bearing durability. Degradation characteristics were tested by attaching to test equipment. At this time, after the durability test under the same load conditions, the mechanical degradation characteristics, that is temperature, vibration according to the three greases types. In addition, the chemical degradation characteristics of the corresponding grease was compared to present the results of mutual correlation analysis.

• Journal of Advanced Marine Engineering and Technology
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• 제37권1호
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• pp.91-98
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• 2013

엔진 및 회전기기의 진동은 선체의 피로도를 증가시켜 내구성을 저하시키는 원인이 된다. 이를 방지하기 위하여 엔진 및 회전기기와 선체사이에는 댐퍼를 부착하여 진동을 최소화 하고 있다. 일반적으로 선박에 부착하는 댐퍼는 수동형 댐퍼로 중 고주파의 특정 진동영역에 대하여 제진 특성을 갖도록 설계되어있지만 저주파영역에서는 그 효과를 기대하기 힘들다. 이에 본 연구에서는 보다 광대역의 진동신호에 대해 높은 제진특성을 얻기 위하여 VCM을 이용한 능동형 제진 장치를 개발하였다. 제진장치를 제어하기 위해 라우스휴리츠 안정조건과 한계감도법을 이용하여 PID제어기를 구성하였고, 제어기 출력은 2상한과 4상한 초퍼회로를 이용하여 VCM을 구동할 수 있도록 하였다. 시뮬레이션과 실제 실험을 통하여 제어알고리즘과 제어장치의 유용성을 확인하였다.

• 한국자동차공학회논문집
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• 제8권1호
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• pp.148-156
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• 2000

For the in-line three cylinder engine whose crankshaft has a phase of 120 degrees, the total sum of unbalanced inertia forces occurring in each cylinder will be counterbalanced among three cylinders. However, parts of inertia forces generated at the No.1 and No.3 cylinders will cause a primary moment about the No.2 cylinder. In order to eliminate this out-of-balance moment, a single balance shaft has been attached to the cylinder block so that the engine durability and riding comfort may be further improved. Accordingly, the forced vibration analysis of the in-line three cylinder engine must be implemented to meet the required targets at an early design stage. In this paper, a method to reduce noise and vibration in the 800cc, in-line three cylinder LPG engine is suggested using the multibody dynamic simulation. The static and dynamic balances of the in-line three cylinder engine are investigated analytically. The multibody dynamic model of the in-line three cylinder engine is developed where the inertia properties of connecting rod, crankshaft, and balance shaft are extracted from their FE-models. The combustion pressure within the No.1 cylinder in three significant operating conditions(1500rpm-full load, 4000rpm-full load and 7000rpm-no load)is measured from the actual tests to excite the engine. The vibration velocities at three engine mounts with and without balance shaft are evaluated through the forced vibration analysis. Obviously, it is shown that the vibration of the in-line three cylinder engine with balance shaft is reduced to the acceptable level .

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.649-655
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• 2011

In this paper, the content to carry out the modal testing and to analyze the data as the target of the main transformer installed on KTX is mentioned. The main transformer for KTX is a structure which is over 10 Ton. For the possibility to occur a stress concentration phenomenon exists, the dynamic durability of the system is experimentally needed to understand. To do this, we obtained the vibration data using an accelerometer, an impact hammer, a measuring instrument and gained the frequency response function of the main transformer based on the acquisition data. In this content, when the theoretical model for structural analysis should be established, we think it will be used for the property verification of analytical model. Also, we expect that the measured and analysed data will offer basic research material to maintain the system and diagnose the condition by monitoring the natural frequency of the main transformer for KTX periodically.

• Advances in aircraft and spacecraft science
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• 제5권2호
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• pp.239-249
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• 2018

Physical tests are performed at various stages of the development cycle of a product, from prototype validation to product qualification. Although costly, there are growing demands for qualification tests like endurance vibration testing to be more representative of the real world. At the same time there are growing demands to assess the durability of these items based on FEA simulation. In this paper, we will explain how to set up a CAE-based test and how to correlate the results with some physical measurements. Specific assumptions will be explained and some advantages of using virtual tests will be highlighted such as the reduction of the number of prototypes needed, investigations on failures, evaluation of the level of reliability via sensitivity analysis, evaluation of the margins are at the end of a successful test. This presentation will therefore focus on explaining and showing how virtual tests can enrich the exploitation of physical tests.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.356-359
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• 2005

Ionic-polymer-metal-composite(IPMC), one of new actuation materials of electroactive polymers plated with noble metallic electrodes is known for the fast bending upon electric field. The IPMC strip bends towards anode under electrical field. It has many merits of low driving voltage, quick responsiveness, high durability, possibility of miniaturizability. In this paper, we studied for developing the large deflection of IPMC according several fabricating parameters. We measured the large deflection by the different process of sandpaper and sandblasting in surface treatment, the initial compositing process and the surface electroding process, and the different counter ions in ion exchanging process. In fundamental, the displacement of IPMC strip depends on voltage magnitude and applied signal frequency and its maximum deformation is observed at a critical frequency, resonant frequency.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.658-661
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• 2008

Vibrations transmitted through rolling tire are major sources of road noise in vehicle interior on the range of $0{\sim}500Hz$. Among various road noises, tire cavity noise makes many problems recently. Vehicle NVH performance has improved better and road surfaces are made well. But tires are changed to high inches and low series. So tire cavity noise becomes more serious. In this paper, a designed material for reducing tire cavity noise is proposed. On the surface inside tire, this material is attached at one position using double-tape. This material disperses the pressure variations inside the tire. So a spindle forces at wheel center are reduced. And tire cavity noise at vehicle interior is also reduced. Durability is verified by tire only test and vehicle test. Noise performance also compared with peak levels after attaching this material.