• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.371-371
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• 2006

The purpose of this study is to provide a fundamental data for efficient and economical reduction method and predict ion method of floor impact noise. In order to get the useful results, the measurement on the vibration transmission characteristics of standard test building with four rooms by using heavy and light-weighed impact source were carried out. In this measurement various conditions such as the change of test structure construction, the pick-up sensor location, the excitation posit ion, and the resilient material types were applied to get the vibration characteristics transmitted from excitation room to adjacent rooms.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(I)
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• pp.156-161
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• 2003

Korean High Speed Train (KHST) has been tested on high speed line in JungBu site since it was developed in 2002. The data acquisition system was used to test successfully the on-line test for proving the dynamic performance of KHST. The recognition of system vibration mode for railway vehicle is essential to understand the characteristics of design for dynamic system and diagnose the dynamic problems of vehicle system during test and operation. But, up to now, there are the efforts to know the system vibration mode within limit of theoretical field only, not experimental approach with systematic method. The theoretical results are too reliable to apply to real design problem, because it is theoretically based on the homogeneous linear system although the real system have the nonlinear characteristics and vary the environmental conditions. Therefor, in this paper, it is proposed the efficient method of vibration analysis for rail vehicle system and this method apply to KHST to recognize the vibration mode characteristics of it. The results show that this method is able to make the system vibration modes for KHST clear.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.96-100
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• 1997

A design modification was made on the 9-th stage wheel dovetail of a high-intermodiate pressure (HIP) turbine rotor for a fossil power plant that necessitates the use of new long-shank buckets for the row. A bucket vibration test is necessary to verify that the new 9-th stage buckets have adequate frequency margin from a nozzle passing frequency when running at speed. A finite element analysis (FEA) has been performed using a commercial S/W to approximately estimate bucket natural frequencies, and thus to help the vibration test. A row of the new buckets has been assembled on the HIP rotor for the vibration tests using dynamic balancing facilities. The tests have been done during deceleration run with air excitation. The test results are compared with the calculation using our empirical formula, and show that the modified design meets the frequency-margin requirements.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.671-672
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• 2012

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.381-382
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• 2007

• Structural Engineering and Mechanics
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• 제46권1호
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• pp.75-90
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• 2013

In order to identify damage of highway bridges rapidly, a method for damage identification using dynamic response of bridge induced by moving vehicle and static test data is proposed. To locate damage of the structure, displacement energy damage index defined from the energy of the displacement response time history is adopted as the indicator. The displacement response time histories of bridge structure are obtained from simulation of vehicle-bridge coupled vibration analysis. The vehicle model is considered as a four-degree-of-freedom system, and the vibration equations of the vehicle model are deduced based on the D'Alembert principle. Finite element method is used to discretize bridge and finite element model is set up. According to the condition of displacement and force compatibility between vehicle and bridge, the vibration equations of the vehicle and bridge models are coupled. A Newmark-${\beta}$ algorithm based professional procedure VBAP is developed in MATLAB, and used to analyze the vehicle-bridge system coupled vibration. After damage is located by employing the displacement energy damage index, the damage extent is estimated through the least-square-method based model updating using static test data. At last, taking one simply supported bridge as an illustrative example, some damage scenarios are identified using the proposed damage identification methodology. The results indicate that the proposed method is efficient for damage localization and damage extent estimation.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1496-1502
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• 2012

엔진에 장착된 자동차용 연료펌프는 외부 및 내부 로터로 구성되어 있으며, 내부 로터는 입구로부터 연료를 흡입하여 출구로 배출한다. 본 연구에서는 로터가 장착된 연료펌프의 성능을 평가하기 위해 해석 및 시험을 수행하였다. 입출구 포트 각도가 0, 15, $30^{\circ}$에서 컴퓨터 시뮬레이션을 통한 연료펌프의 유동 특성을 해석하였다. 가장 우수한 유동 특성을 가진 펌프를 결정한 후 진동 특성을 해석하였다. 그 결과 유량은 입출구 포트 각도가 $0^{\circ}$에서 191.0 LPH로 가장 우수하게 나타났으며, 진동은 0.866 $^m/s^2$으로 계산되었다. 진동 시험 결과를 통해 연구된 펌프가 기존의 펌프에 비해 작은 진동을 가지고 있음을 알 수 있었다. 그리고 두 펌프의 고유진동수들은 거의 일치하였다. 따라서 연구된 펌프의 성능이 우수하다는 것을 알 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.717-720
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• 2005

Acoustic loads generated by a rocket propulsion system cause severe random vibrations on payloads. In developing a new launch vehicle, a random vibration level must be specified before the detailed design of payloads or electronic equipments. This paper deals with prediction procedures of a random vibration level on payload section of KSLV-I. The prediction is based on statistical energy analysis. In order to verify the prediction methodology, test and analysis on a sub-scale payload section are performed. The predicted results subject to very high level of acoustic loads show a good agreement with the test results performed in the high intensity acoustic chamber. The predicted random vibration level on payload section of KSLV-I is also presented in this paper.

• 한국소음진동공학회논문집
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• 제15권12호
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• pp.1389-1397
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• 2005

Since blast-induced vibration may cause serious problem to the rock mass as well as the nearby structures, the prediction of blast-induced nitration and the stability evaluation must be performed before blasting activities. Dynamic analysis has been increased recently in order to analyze the effect of the blast-Induced vibration. Most of the previous studies, however, were based on the continuum analysis unable to consider rock joints which significantly affect the wave propagation and attenuation characteristics. They also adopted pressure corves estimated tv theoretical or empirical equations as input detonation load, thus there were very difficult to reflect the characteristics of propagating media. In this study, therefore, we suggested a dynamic distinct element analysis technique which uses velocity waveform obtained from a test blast as an input detonation load. A distinct element program, UDEC was used to consider the effect of rock joints. In order to verify the validity of proposed method, the test blast was simulated. The predicted results from the proposed method showed a good agreement with the measured vibration data from the test blast. Through the dynamic numerical modelling on the planned road tunnel and slope, we evaluated the effect of blast-induced nitration and the stability of rock slope.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.840-840
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• 2003

Operational Modal Analysis (OMA) is a technique for identification of modal parameters by measurement of only the system's response. On many lightweight structures, such as load-speaker cones and disk drive read/write heads, is impossible or impractical to measure the input forces. Another characteristic of lightweight structure is their sensitivity to mass loading from sensors. The Scanning Laser Doppler Vibrometry(SLDV) allows response measurements to be taken without mass loading. One disadvantage of OMA testing compared to tradition input output modal testing is the OMA mode shapes are un-scaled. This means that the mode shape obtained from an OMA test can not used for analytical structural modification studies. However, the un-scaled mode shapes from an OMA test can be used to update a Finite Element Model (FEM). The updated FEM can then be used to analytically predict the effect of structural modifications. This paper will present the results of an OMA test performed on a simple plate and motor in operating conditions. The un-scaled mode shapes from this test will be used to update a FEM model of the system. The updated FEM model will be then be used to predict the effect of attaching a mass to the plate. The shapes predicted by the FEM for the modified system will be compared to a second OMA test on the modified system