• 한국철도학회논문집
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• 제10권6호
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• pp.806-811
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• 2007

탈선은 차륜 플렌지가 레일에 접촉할 때 발생하는 횡방향의 힘이 커져 차륜이 레일을 이탈하는 현상이다. 탈선 또는 주행안전도를 평가하는 대표적인 기준은 탈선계수이다. 차륜에 스트레인게이지를 부착하여 탈선계수를 측정하는 기존방법은 대단히 복잡하고 측정의 실패확률도 높으며, 고도의 측정기술과 고가의 비용이 요구되고 있다. 따라서 안전성확인이 필요한 그 시점에 즉시 확인하지 못하고 있어 안전확보에 어려움을 겪고 있다. 본 논문에서는 차륜과 레일간의 접촉력인 윤중과 횡압을 쉽게 측정할 수 있는 방안을 집중적으로 연구하였으며, 가속도과 변위의 거동만으로 탈선 가능성을 예측할 수 있는 새로운 탈선계수 측정방법을 제시하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제27권2호
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• pp.198-208
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• 2003

• 한국전산구조공학회논문집
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• 제13권1호
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• pp.87-95
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• 2000

양단이 단순지지 상태이고, 정현상으로 taper진 부재의 두 고유치(탄성임계하중과 횡방향 고유진동수)를 유한요소법으로 산정하였다. 그 결과로 얻어진 고유치의 계수들을 실무에 종사하는 구조 기술자들이 쉽게 이용할 수 있도록 각각의 경우에 대하여 간단한 대수 방정식으로 표시하였다. 유한요소법으로 구한 고유치 계수값과 대수 방정식에 의한 추정 계수값들의 상관계수는 어느 경우에나 거의 단위치(1)에 가까운 값으로 대수 방정식의 정당성을 뒷받침 하였다. 횡방향 진동수에 미치는 압축하중의 영향도 검토하였다. 이를 위하여 부재에 작용하는 축방향력을 차례로 증가시키면서 여기에 대응하는 진동수를 산정하였다. 그 결과 압축하중비 (P/P/sub cr/)와 진동수 비의 제곱 ((ω/ω/sub 0/)²)의 합은 어느 경우에나 거의 단위치(1)로 나타났다.

• 한국소음진동공학회논문집
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• 제22권11호
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• pp.1128-1136
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• 2012

This paper analyzes the vibration characteristics of an optical pickup actuator, which has six wire-suspensions and is used in optical disc drives(ODDs). The vibration characteristics of the actuator is mathematically described by analyzing its beam configuration and motion condition confined to lateral and longitudinal directions of the beams. The accuracy of the vibration characteristics is proved by comparing mode frequencies with a finite element analysis. Finally, it is shown that mode frequencies and shapes can be modified by changing design parameters in mathematical expressions.

• Journal of Positioning, Navigation, and Timing
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• 제11권2호
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• pp.119-126
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• 2022

This paper presents a method to reduce the vibration-induced noise effect of an inertial measurement device mounted on a self-driving vehicle. The inertial sensor used in the GNSS/INS integrated navigation system of a self-driving vehicle is fixed directly on the chassis of vehicle body so that its navigation output is affected by the vibration of the vehicle's engine, resulting in the degradation of the navigational performance. Therefore, these effects must be considered when mounting the inertial sensor. In order to solve this problem, this paper proposes to use an in-house manufactured vibration suppression device and analyzes its impact on reducing the vibration effect. Experimental test results in a static scenario show that the vibration-induced noise effect is more clearly observed in the lateral direction of the vehicle, but can be effectively suppressed by using the proposed vibration suppression device compared to the case without it. In addition, the dynamic positioning test scenario shows the position, speed, and posture errors are reduced to 74%, 67%, and 14% levels, respectively.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1990년도 추계학술대회논문집; 한양대학교, 서울; 24 Nov. 1990
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• pp.199-203
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• 1990

본 연구에서는 일반적인 형상을 갖는 회전축에서 축 방향 하중과 토오크를 각각 또는 동시에 고려할 수 있는 전달 행렬을 수식화하였고, 이에 의한 진 동 특성을 해석하기 위하여 강제진동 해석 및 자유진동 해석을 수행하였으 며, 해석결과에 대한 신빙성을 얻기 위하여 과도진동 해석 및 이산화 FFT를 통하여 검산기능을 추가하였다. 그리고 전달 행렬법에 새로운 고유치 수치해 법과 수치 적분법의 적용을 통하여 `수렴성과 안정성을 개선하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.439-443
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• 2001

The steering wheel vibrations such as shimmy, brake judder and shake are affected by the vibration characters of steering and suspension. For the analysis of shimmy, nonuniformities of tire can be considered the major sources. This study investigates unbalances and uniformities of tire in which the lateral force variation is highly correlated with shimmy. The hardness of suspension bushes can be modified to change the dynamic behavior of suspension that is effective to reduce the sensitivity of shimmy.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.667-668
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• 2012

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 춘계학술대회 논문집
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• pp.85-90
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• 1996

In the word, there is varied types of vibration, and these affect the mechanical industry. In this paper is plates with two parallel sides fixed. Electronic speckle pattern interferometry (ESPI) is one of the optical nondestructive testing technique. By using the ESPI, vibration modes for excitation point, a/b(ratio of longuitudinal and lateral length), and kind of specimen are measured and compared qualitatively with theoritical analysis that Warburton proposed.

• 대한인간공학회지
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• 제32권4호
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• pp.355-361
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• 2013

Objective: The aim of this study is to investigate the gender-differences in vibrotactile responses(sensitivity and displeasure) of residual forearm simulated by vibration stimulation in upper limb(trans-radial) amputees. Background: Several studies have reported that vibration stimulation using the haptic vibrator is one the most effective methods for delivering sensation to an amputees. However, few studies have reported the perception to haptic vibratory stimulus, particularly sensitivity and displeasure. Method: We set up a custom-made vibration stimulation system that included 6 actuators(3 medial parts and 3 lateral parts) and a graphical user interface(GUI)-based acquisition system to investigate changes in residual somatosensory sensibility and displeasure in the forearm of upper limb(trans-radial) amputees. Vibration actuators were attached at the 25%-point on the proximal forearm. Stimulation with 32Hz, 64Hz, or 149Hz of frequency was used for the sensitivity tests and with 32~257Hz of frequency was used for the discomfort experiments. The subjective responses were evaluated on a 10 point scale. Results: The results showed that vibrotactile sensory perception in male amputees were higher than that in female amputees. In male amputees, the response at lateral area of forearm was the most sensitive than medial area; but, female amputees showed similar sensitive areas. Subjects did not experience any discomfort during vibrotactile stimuli. Conclusion: Vibrotactile response in the amputees was dependent on gender as well as area stimulated by vibration. Application: The results might contribute to develop the vibrotactile feedback system for the amputees.