• 한국소음진동공학회논문집
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• 제14권8호
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• pp.741-748
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• 2004

The vibration and buckling characteristics of the capsule for fuel irradiation test are studied. The natural frequencies of the capsule in air and under water are obtained by modal testing and finite element (FE) analysis using ANSYS program, and accelerations with flow are measured to estimate the compatibility with the operation requirement of the HANARO reactor. The experimental fundamental frequencies of the capsule in the x and z direction are 8.5 Hz and 8.75 Hz in air, and 7.5 Hz and 7.75 Hz under water, respectively. The maximum amplitude of accelerations under the normal operating condition is measured as 11.0 m/s$^2$ that is within the allowable vibrational limit(18.99 m/s$^2$) of the reactor structure. Also, the maximum displacement at 100％ flow is calculated as 0.13 mm which is not interference with other nearby structures. FE analysis results show that the natural frequencies are found to be similar to those of the modal testing when three supporting parts are considered as simply supported conditions. From the buckling analysis, when the loading tool is applied, the critical buckling load of the capsule is 233 N.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.479-484
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• 2005

The test blasts were carried out by detonating some single blastholes at two upper sites of the underground storage cavern the crude oil. One was performed at the entrance site of the construction tunnel and the other at the middle part of the underground storage cavern. Based on the blast-induced vibration measured by the test blasts, we suggested the propagation equations of blasting vibration that were capable of estimating the peak particle velocity. In addition, in order to assess the stability of the nearest ground storage tank, we did the frequency analysis and the response spectrum analysis with the particle velocity-time history and the particle acceleration-time history that were measured by the test blast carried out on the entrance site of the construction tunnel. In result, it was predicted that the displacement on the highest part of the tank shell was less than the allowable displacement.

• 화약ㆍ발파
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• 제40권4호
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• pp.47-56
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• 2022

당 현장 주변에 보안물건이 위치하고 있어, 기존 설계상에 176m 구간이 무진동 기계식 굴착공법으로 설계되었으나, 시공성 및 경제성 향상을 위하여 전자뇌관 미진동 발파공법을 제안하였다. 검토 결과, 발파소음, 진동 모두 허용기준 이내의 안전성을 확보하여 해당 구간에 대하여 전자뇌관 미진동 발파공법 적용 가능성을 확인하였다. 아울러 검토 구간에서 무진동 굴착공법과 전자뇌관 미진동 발파공법을 비교한 결과, 공사 기간을 88일 단축하여 경제적으로 큰 이점이 있는 것으로 평가되었다.

• 대한기계학회논문집
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• 제19권6호
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• pp.1402-1410
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• 1995

An influence coefficient method with an optimal correction balancing algorithm is developed for balancing a high-speed flexible rotor system. Conventional flexible balancing algorithms such as least square and weighted least square algorithms may not satisfy allowable residual vibration levels in certain speed ranges, while the optimal correction balancing method can be more effective in controlling vibration levels in a target speed. Related analyses were reviewed and applied to a test rig to show the effectiveness of the optimal correction balancing method.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권4호
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• pp.211-216
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• 2010

Recently a Wide Chord Tip (WCT) propeller has been developed and applied to a commercial ship by STX Offshore & Shipbuilding. It is reported that the WCT propeller significantly reduces pressure fluctuations and also ship's noise and vibration. On the sea trial, vibration magnitude in the accommodations at NCR was measured at 0.9mm/sec which is only 10% of international allowable magnitude of vibration (9mm/sec). In this paper, a design method for increasing performance of the marine propellers including the WCT propeller is suggested. It is described to maximize the performance of the propeller by adjusting expanded areas of the propeller blade. Results show that efficiency can be increased up to over 2% through the suggested design method.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1244-1250
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• 2008

The site of interest is a residence redevelopment area which has excavation construction with cut-off walls. The site is located over Dong-Mang-Bong tunnel and Seoul No. 6 subway tunnel. This study analyzed numerically the influence of vibrations from No. 6 subway tunnel to the basement of the redeveloped apartment away from the distance about 11m. Kyoung-bu highspeed railway's time history model with linearly reduced maximum acceleration is applied to take into the subway maximum speed of 75km/h. The maximum velocity of vibration for the cross section of the interest was estimated as 0.28cm/sec which satisfied the allowable standard of 0.5cm/sec for apartment and residence of Seoul.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2005년도 추계 학술대회
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• pp.49-54
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• 2005

In the case of a sensitive equipment, it require a vibration free environment to provide its proper function. Especially, lithography and inspection device, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved Giga Class semi conductor wafers. The aim of this study is to evaluate the allowable vibration response of a precision inspect ion equipment, which has some trouble in field, by using experimental measurement data and to proposal a proper ant i-vibration method.

• 센서학회지
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• 제20권5호
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• pp.336-342
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• 2011

Recently, the LCD manufacturing industries try to maximize the productivity of LCD panels due to sharp increase in the market need of LCD display. Usually, the increase in manufacturing speed induces additional vibration of glasses and manufacturing machineries. This kind of vibration can induce bad effects on the manufacturing accuracy, and even can damage the glasses. The vibration signal of glass itself is very useful to predict the allowable maximum level of manufacturing speed. Therefore, it is necessary to measure the vibration of the glass itself and a very thin vibration measurement system attachable on the glass is needed. Since in some processes the glasses need to go through very thin gaps such as 2.5mm, We develop a glass vibration measurement system with the thickness of 1.3mm. The system measures the glass vibration using MEMS type accelerometers and store vibration data in a Nand-Flash memory. The performance of the develop system has been verified on a real LCD manufacturing line and the accuracy of vibration measurement is comparable with that of an accurate commercial vibration measurement system.

• 화약ㆍ발파
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• 제36권1호
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• pp.34-38
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• 2018

철도터널 발파 시 근접한 보안물건에 대하여 발파진동 및 소음을 제어하고, 여굴방지를 목적으로 전자뇌관과 비전기뇌관을 조합한 발파시스템(Supex Blasting Method)을 적용하여 보성~임성리 ${\bigcirc}{\bigcirc}$ 철도건설공사에서 시험발파를 실시하였다. 그 결과 발파진동과 소음은 허용기준치 이내로 측정된 것으로 나타났다. 결과적으로 전자뇌관과 비전기뇌관을 조합한 터널발파 시스템은 공사비 절감, 발파진동 및 소음제어를 통한 민원방지 효과 및 여굴제어로 굴착예정선 주변의 암반손상권을 최소화하는 것으로 나타났다.

• 터널과지하공간
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• 제13권4호
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• pp.316-320
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• 2003

본 연구에서는 불규칙한 천공장이 발파진동에 미치는 영향에 관하여 연구하였다. 각각 2.lm 2.3m, 2.4m의 천공장에 대한 최대 진동속도와 삼승근환산거리의 관계를 비교 분석한 결과동일 환산거리에서 천공장의 크기가 길어질수록 더 큰 진동속도를 보였다. 그러므로 허용진동 속도이하의 일정범위의 발파 진동치를 유지하기 위하여서는 규clr적인 천공이 되도록 관리가 필요할 것으로 판단된다.