• Title/Summary/Keyword: Vibration condition

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An Analysis for Coupled Vibration of Vehicle and Bridge Using Fourier Sine Transformation (FOURIER변환을 이용한 차량과 교량의 연성 진동 해석)

  • 류윤선
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1998.04a
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    • pp.45-50
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    • 1998
  • The coupled vibration occurs between traveling vehicle and bridge, when vehicle runs on it. The natural frequency of this coupled system is dependent on the contact position of vehicle and bridge, that is, time-varying system. The calculations of these natural frequencies are very complicated, and often carried out by using Green function theory, series. But, these methods have any limitations, such as, supporting condition, boundary condition. In this paper, on the coupled system constructed by the concentrated mass and elastically supported beam, an analytical method of natural frequency is proposed by using Fourier sine transformation. The results are compared and discussed with numerically calculated ones.

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A study on the Base Plate to reduce vibration for Refrigerator (Base Plate 연구를 통한 냉장고 진동 저감 방안 고찰)

  • Kim, Jung-Seon;Thuy, Tran Ho Vinh;Kook, Jung-Hwan;Wang, Se-Myung;Lee, Dong-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.340-343
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    • 2007
  • In this paper, we present our method to reduce vibration of the base plate of a refrigerator by avoiding resonance between base plate and compressor operation. To verify the modes of the base plate, FE models of the base plate with free-free condition and applied boundary condition were built and validated by results from experimental modal analysis. Operating Deflection Shape analysis was applied to find the sensitive area on the base plate during compressor operation. In optimization process, Finite Difference Method - based sensitivity analysis is used to detect the most sensitive area. Finally, based on this numerical result, we will make beads on the base plate to reduce vibration of refrigerator.

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Analysis of The Behavior of Kurtosis By Simplified Model of One Sided Affiliated Impact Vibration

  • Takeyasu, Kazuhiro;Higuchi, Yuki
    • Industrial Engineering and Management Systems
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    • v.4 no.2
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    • pp.192-197
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    • 2005
  • Among many amplitude parameters, Kurtosis (4-th normalized moment of probability density function) is recognized to be the sensitive good parameter for machine diagnosis. Kurtosis has a value of 3.0 under normal condition and the value generally goes up as the deterioration proceeds. In this paper, simplified calculation method of kurtosis is introduced for the analysis of impact vibration with one sided affiliated impact vibration which occurs towards the progress of time. That phenomenon is often watched in the failure of such as bearings’ outer race. One sided affiliated impact vibration is approximated by one sided triangle towards the progress of time and simplified calculation method is introduced. Varying the shape of one sided triangle, various models are examined and it is proved that new index is a sensitive good index for machine failure diagnosis. Utilizing this method, the behavior of kurtosis is forecasted and analyzed while watching machine condition and correct diagnosis is executed.

Vibration Analysis of Vehicle Seat Depending on Driving Condition (주행조건에 따른 자동차 시트 진동특성 연구)

  • Kang, Jae-Young;Kim, Key-Sun;Choi, Seok-Min;Choi, Tae-Jin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.3
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    • pp.110-115
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    • 2010
  • This paper studies the vibration characteristics of a vehicle seat on several driving conditions. Modal test for a vehicle seat is conducted for the three different boundary conditions: on the rigid jig, BIW and the full vehicle. In driving on various road conditions and speeds, vibration level is measured at several locations including seat mounting and seat-back. The vibration pattern for each driving condition is found where the suspension mode and the 1st bending and torsion modes of the seat make the major contribution on it.

Torsional Vibration Analysis in Large Two-Stroke Diesel Engines for Stationary Power Plants. (발전용 대형 2행정 디젤 엔진의 비틈진동 해석)

  • Park, Jong-Po;Park, Hui-Ju
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.10 s.181
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    • pp.2529-2534
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    • 2000
  • Torsional vibration analysis in a large two -stroke low speed diesel engine and generator system for stationary power plants is performed to verify that the vibration characteristics of shafting system meet design requirements. Our own developed S/W is employed for the analysis, whose results are evaluated comparing with measurements. Vibration analysis results of the system are presented according to the change of loading(unload, 100%load, 110% load) and operating(mis-firing, uneven firing) conditions of the stationary power plants.

Condition Monitoring in a Gear with Initial Pitting Using Phase Map of Wavelet Transform (웨이블렛 변환의 위상 지도를 이용한 초기 피팅 결함을 갖는 기어의 상태 감시)

  • 심장선;이상권
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.590-595
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    • 2001
  • Vibration transient generated by developing localized fault in gear can be used as indicators of condition monitoring in a gear. In this paper, we propose the phase map for a fault signal using continuous wavelet transform to detect this vibration transient. Local fault induces the abrupt fluctuation of load exciting tooth and phase lag in the vibration signal measured on the gearbox. The relatively large fault like "tip breakage" easily can be detected by the clear fluctuation of exciting load. However, minor fault like "initial pitting" cannot be detected using the load fluctuation. To detect this kind of minor fault, the phase map for a fault signal is taken into account. The phase lag by minor fault is observed well in the phase map.

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Dynamic Characteristics of Bolted Joint in Tube Line by External Vibration (외부 가진을 받는 관로계에서 볼트 결합부의 동특성)

  • Park, T.W.;Kim, Y.K.;Shin, G.S.
    • Journal of Power System Engineering
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    • v.5 no.4
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    • pp.38-43
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    • 2001
  • This paper describes the effect of dynamic characteristics in tube line by external vibration conveying fluid with the power steering system. By the experimental analysis we found out that the factor of system vibration is the fluid-structure interaction of tube line. In fluid-filled tube system we study on the influence that the natural frequency of system and the frequency of wave motion produce upon through experiment. Experiments are modal test, frequency response function in continuous system, and vibrating tests when the system is driving with bolted clamping joint condition. From the results of the experimental studies, we obtained that the natural frequencies of system are very important than the wave induced vibrations. And we found that the tendency of system vibration level was decreased by bolting force, bolting condition and clamping distance.

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Servo Track Writing for Ultra-High TPI Disk Drive in Low Density Medium Condition (초고밀도 디스크 드라이브를 위한 저밀도 작동 환경에서 서보 트랙 기록 방법에 대한 연구)

  • 한윤식;김철순;강성우
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.736-741
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    • 2004
  • In high-capacity disk drives with ever-growing track density, the allowable level of position error signal (PES) is becoming smaller and smaller. In order to achieve the high TPI disk drive, it is necessary to improve the writing accuracy during the STW(servo track writing) process through the reduction of TMR sources. Among the main contributors of the NRRO(Non-Repeatable Run-out) PES, the disk vibration and the HSA(head-stack assembly) vibration is considered to be one of the most significant factors. Also the most contributors of RRO(Repeatable Run- out) come from the contributors of NRRO which is written-in at the time of STW(servo track writing) process. In this paper, the experimental test result shows that the effect of NRRO on servo written-in RRO effectively can be reduced through a STW process under low dense medium condition such as semi-vacuum.

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Historical Background for Derivation of the Differential Equation mẍ+kx = f(t) (미분방정식 mẍ + kx = f(t)의 역사적 유도배경)

  • Park, Bo-Yong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.4
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    • pp.315-324
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    • 2011
  • This paper presents a historical study on the derivation of the differential equation of motion for the single-degree-of-freedom m-k system with the harmonic excitation. It was Euler for the first time in the history of vibration theory who tackled the equation of motion for that system analytically, then gave the solution of the free vibration and described the resonance phenomena of the forced vibration in his famous paper E126 of 1739. As a result of the chronological progress in mechanics like pendulum condition from Galileo to Euler, the author asserts two conjectures that Euler could apply to obtain the equation of motion at that time.

The Study on the Correlation of Vibration, Wear and Temperature for Rubbing in Rotating Machinery (마멸현상에서 발생하는 회전기 시스템의 진동.마모.온도의 상관 관계 연구)

  • 백두진;김승종;윤의성;김창호;공호성;장건희;이용복
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.453-459
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    • 2002
  • In this paper. the correlation among vibration. wear and temperature are experimentally investigated when rubbing is caused by static and dynamic forces. Each measurement reflects the characteristics of the system and is useful in detecting and diagnosing the current status of rotating machinery. For experiment, the rotor system with lubricating equipment such as trochoid pump, oil tank and wear detecting sensor is implemented to simulate the rubbing condition. Experimental results show that significant change in wear quantity can be notified when vibration signal is changed by rubbing. The results can be applied to system monitoring and fault diagnosis in rotating machinery.

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