• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1992.10a
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• pp.31-35
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• 1992

자동차 관련 소음 및 진동중 엔진과 관련된 것은 흡.배기계 소음과 엔진 자 체의 각 구동 부위 및 연소실 소음으로 대별하여 볼수 있다. 특히 연소실 소 음의 경우에는 엔진 내부에서 발생하는 진동과 압력파가 엔진을 진동시키고, 이러한 엔진의 진동이 방사음을 발생시켜 형성되는 만큼 그 해석 및 공학적 접근 방법이 용이하지 않다. 연소실 소음은 압력의 갑작스런 변화에 의한 폭 발소음과 피스톤과 실린더 벽면의 충돌에 의한 피스톤 슬랩(piston slap)으로 크게 구분할 수 있으며 압력이 높지 않고 압력의 변화가 빠르지 않을 경우 에는 피스톤 슬랩이 기계적 소음의 주 원인이 되는 것으로 알려져 있다. 본 고에서는 피스톤 슬랩에 의한 진동 현상을 예측하기 위한 이론적 접근 방법 을 제시하고 이의 타당성을 검증하기 위한 실험적 방법을 제시하고자 한다. 또한, 피스톤과 실린더의 간극 진단을 위해 슬랩 신호를 이용하는 방법에 대 해 살펴보고, 피스톤과 실린더의 충돌 속도를 통해 슬랩 신호를 줄이기 위한 엔진의 설계 방법에 대해 살펴보고자 한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.2
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• pp.67-72
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• 2001

대상으로 하는 시스템의 입출력신호에 근거하여, 시스템의 수학적 모델을 결정하는 것을 총칭하여 시스템식별이라 한다. 본 논문에서는 지진응답 관측치를 입출력신호로 하여 조건부대치를 최적치로 판단하는 비선형근사필터법을 사용한 건축구조물의 지진응답추정 및 파라미터식별에 관하여 논한다. 비선형근사필터법에 의한 건축구조물식별의 유효성의 적용성을 판단하기 위해, 진동대를 사용하여 강구조시험체의 진동실험을 행하고 결과적으로 얻어진 시험체의 수학적 모델에 대한 지진응답 수치해석결과와 진동실험에서의 관측기록을 비교하여 본 식별법의 타당성을 보인다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.121-129
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• 2017

In this paper, the shake table test for the masonry infilled reinforced concrete frame with non-seismic details was carried out in order to evaluate its dynamic behaviour and damage under seismic condition. The tested specimens were the RC frame and the masonry infilled RC frame and the dynamic characteristics, such as a resonant period, acceleration response, displacement response and base shear force response, were compared between them. As a result of the shake table test, RC frame specimen had flexural cracks at the top and bottom of the column and shear cracks at the joints. In the case of masonry infilled RC frame, the damage of the frame was relatively minor but the sliding cracks and diagonal shear cracks on the masonry wall were severe at the final excitation. The resonant period of infilled RC frame specimen was shorter than that of the RC frame specimen because the masonry infill contributed to increase the stiffness. The maximum displacement response of the infilled RC frame specimen was decreased by about 20% than the RC frame specimen. It was analyzed that the masonry infill wall applied in this study contributed to increase the lateral strength of the RC frame with non - seismic detail by about 2.2 times and the stiffness by about 1.6 times.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.139-144
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• 1991

4WD자동차의 엔진마운트 설계기법의 정리 및 실제차량의 실험적 mode 해 석을 통해 다음과 같은 결론을 얻었다. 1. 4WD자동차의 엔진마운트 설계 개념을 체계화시키고, 이를 실제차량에 대 해서 실험적 mode해석을 해본 결과 잘 일치함을 확인하였다. 2. power transmission system에 부가되는 장치(front propeller shaft)의 영 향을 검토한바, frequency shift현상이 발생함을 확인하였다. 이러한 영향은 이들 부가장치들의 질량증가 및 관성모멘트의 변화로 기인되며, 질량의 증가 보다는 관성모멘트의 영향이 상대적으로 크리라 판단된다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.6
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• pp.620-627
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• 2009

Shaking table test was carried out to obtain dynamic characteristics of TLCDs with uniform and non-uniform sections for both horizontal and vertical tubes. The input to the table is harmonic acceleration with constant magnitude. The output is horizontal dynamic force which is measured by load cell installed below the TLCD. Transfer functions are experimentally obtained using the ratio of input and output. Natural frequency, the most important design factor, is compared to that by theoretical equation for TLCDs with five different water levels. System identification process is performed for experimentally obtained transfer functions to find the dynamic characteristics of head loss coefficient and effective mass of TLCDs. It is found that their magnitudes are larger for a TLCD with non-uniform section than with uniform section and natural frequencies are close to theoretical ones.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.11
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• pp.129-136
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• 2019

Non-structural elements are vulnerable to earthquake ground motion. In this study, an experimental study for the electrical non-structural element was performed using tri-axial shaking table tests. A 100kVA UPS(Uninterruptible Power Supply system) was used as the test specimen. The test specimen was anchored to the concrete slab using the conventional installation detail. The input acceleration were generated in accordance with ICC-ES AC156 code. Scale factors of the input acceleration with respect to the required response spectrum defined in ICC-ES AC156 were from 25% to 600%. Based on the test results, damage and dynamic characteristics of UPS were evaluated and analyzed including natural frequency, damping ratio, acceleration time history response, dynamic amplification factor and relative displacement.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.2
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• pp.49-57
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• 1997

It is necessary to conduct researches about seismic design and analysis to protect various structures from earthquakes which are one of the most destructive natural disaster to human civilization. To assess the seismic capacity of structure, not only analytical but also experimental researches are important. Currently, pseudodynamic test known as computer-actuator on-line test is one of the available test methods to assess seismic capacity of structure without using shaking table. In this paper seismic capacity of simple one-degree of freedom structure was estimated by pseudodynamic test. Good agreement between the experimental and analytical results was obtained. Better results would be obtained when more sophisticated measuring and controlling instruments are available.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.23-29
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• 2017

In this study, a post-correlation analysis for shaking table test of square water storage tank is presented for the use of advances in earthquake-resistant design of liquid storage tank. For this purpose, the ANSYS CFX program is selected for the CFD analysis. Sensitivity analysis for resonant sloshing motion in terms of grid size and turbulence model suggested that (1) horizontal grid size as well as vertical grid size is a key variable in the sloshing analysis, and (2) the SST turbulence model is best for the sloshing analysis. Finally, correlation analyses for a non-resonant harmonic input and scaled earthquake excitation of the El Centro (1940) NS component are carried out using the grid and turbulence model established through the post-correlation analysis for the resonant motion. As a result, sloshing time histories by the CFD analysis agreed very well with the test results.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.451-458
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• 2008

The near-fault ground motion (NFGM) is characterized by a single long period velocity pulse of large magnitude. NFGM's have been observed in recent strong earthquakes, Izmit Turkey (1999), Kobe Japan (1995), Northridge USA (1994), etc. These strong earthquakes have caused considerable damage to infrastructures because the epicenter was close to the urban area, called as NFGM. Extensive research for the near-fault ground motion (NFGM) have been carried out in strong seismic region, but limited research have been done for NFGM in low or moderate seismic regions because of very few records. The purpose of this study is to investigate and analyze the effect of near-fault ground motions on reinforced concrete (RC) bridge piers with lap-spliced longitudinal reinforcing steels. The seismic performance of four RC bridge piers under near-fault ground motions was investigated on the shake table. In addition, a RC bridge pier is subjected to pseudo-dynamic loadings. Test results showed that large residual displacements were observed in RC bridge piers under NFGM. RC specimens on the shake table failed at relatively low displacement ductility, compared with the displacement ductility of RC bridge pier subjected to pseudo-dynamic loadings.

• Journal of the Korean Geotechnical Society
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• v.33 no.7
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• pp.17-28
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• 2017

This paper presents the investigation of dynamic behavior of a single pile in dry sand based on 1g shaking table tests. The natural frequency of soil-pile system was measured, and then a range of loading frequency was determined based on the natural frequency. Additionally, the studies were performed by controlling loading accelerations, pile head mass and connectivity conditions between pile and cap. Based on the results obtained, relatively larger pile head displacement and bending moment occur when the loading frequency is larger than the natural frequency of soil-pile system. However, the slope of the p-y curve is smaller in the similar loading frequency. Also, it was found that inertia force like input acceleration and pile head mass, and relation of the natural frequency of soil-pile system and input frequency have a great influence on the slope of dynamic p-y curve, while pile head conditions don't.