• Title/Summary/Keyword: 진동대

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Optimal Design of a Composite Solar Panel for Vibration Suppression (진동 저감을 위한 복합재료 태양전지판의 최적설계)

  • Kim, Yongha;Kim, Hiyeop;Park, Jungsun
    • Journal of Aerospace System Engineering
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    • v.12 no.6
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    • pp.50-57
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    • 2018
  • This paper proposes the use of supports as passive vibration absorber to a composite solar panel for a high-agility satellite. We further defined the dynamic model of the composite solar panel with the help of the Ritz method and verified vibration suppression performance of the support by performing vibration analysis. Finally, this research ensures optimal design of the composite solar panel with the support for maximizing vibration suppression performance in limited mass. The proposed results of the optimal design can be applied in actual structural design of satellites.

Dynamic Frictional Behavior of Saw-cut Rock Joints Through Shaking Table Test (진동대 시험에 의한 편평한 암석 절리면의 동적 마찰거동 특성)

  • Park Byung-Ki;Jeon Seokwon
    • Tunnel and Underground Space
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    • v.16 no.1 s.60
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    • pp.58-72
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    • 2006
  • In recent years, not only the occurrences but the magnitude of earthquakes in Korea are on an increasing trend and other sources of dynamic events including large-scale construction, operation of hi띤-speed railway and explosives blasting have been increasing. Besides, the probability of exposure fir rock joints to free faces gets higher as the scale of rock mass structures becomes larger. For that reason, the frictional behavior of rock joints under dynamic conditions needs to be investigated. In this study, a shaking table test system was set up and a series of dynamic test was carried out to examine the dynamic frictional behavior of rock joints. In addition, a computer program was developed, which calculated the acceleration and deformation of the sliding block theoretically based on Newmark sliding block procedure. The static friction angle was back-calculated by measuring yield acceleration at the onset of slide. The dynamic friction angle was estimated by closely approximating the experimental results to the program-simulated responses. As a result of dynamic testing, the static friction angle at the onset of slide as well as the dynamic friction angle during sliding were estimated to be significantly lower than tilt angle. The difference between the tilt angle and the static friction angle was $4.5\~8.2^{\circ}$ and the difference between the tilt angle and the dynamic friction angle was $2.0\~7.5^{\circ}$. The decreasing trend was influenced by the magnitude of the base acceleration and inclination angle. A DEM program was used to simulate the shaking table test and the result well simulated the experimental behavior. Friction angles obtained by shaking table test were significantly lower than basic friction angle by direct shear test.

방음벽의 설계인자와 성능

  • 황철호
    • Journal of KSNVE
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    • v.12 no.6
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    • pp.395-403
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    • 2002
  • 1997년 8월 어느 날 국내 자동차 등록 대수가 세계에서 11번째로 천만대를 넘었다는 요란스러운 뉴스가 있었다. 그로부터 5년 뒤인 2002년 2월 20일 자동차 등록 대수가 1300만대를 돌파하면서 가구당 보유차량이 1대를 넘어섰다. 이는 미국의 국민 1인당 자동차 1대, 일본과 영국 등의 2인당 1대에는 못 미치지만 노르웨이나 덴마크 등 북유럽 선진국과는 맞먹는 수치이다. 자동차로 인한 환경오염에 여러 가지가 있지만, 소음만을 기준으로 할 때, 우리나라의 교통소음 발생 절대 총량이 선진국들 뺨치게 높다는 의미이다.(중략)

Seismic performance evaluation of circular composite columns by shaking table test (진동대 실험을 통한 원형 합성 기둥의 내진 성능 평가)

  • Shim, Chang-Su;Chung, Young-Soo;Park, Ji-Ho;Park, Chang-Young
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.5
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    • pp.71-81
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    • 2007
  • For the design of composite bridge piers, detail requirements for the reinforcements is not clear to satisfy the required seismic performance. Composite bridge piers were suggested to reduce the sectional dimensions and to enhance the ductility of the columns under earthquake loadings. In this paper, five specimens of concrete encased composite columns of 400mm diameter with single core steel were fabricated to investigate the seismic performance of the composite columns. Shaking table tests and a Pseudo-Dynamic test were carried out and structural behavior of small-scaled models considering near-fault motions was evaluated. Test parameters were the pace of the transverse reinforcement, lap splice of longitudinal reinforcement and encased steel member sections. The displacement ductility from shaking table tests was lower than that from the pseudo-dynamic test. Limited ductile design and 50% lap splice of longitudinal reinforcement reduced the displacement ductility. Steel ratio showed significant effect on the ultimate strength. Lap splice and low transverse reinforcements reduced the displacement capacity. The energy dissipation capacity of composite columns did not show significant difference according to details.

A Study on Seismic Retrofit Design of the Stabilized Piles by 1g Shaking Table Tests and Pseudo-static Analysis (1g 진동대 실험 및 등가정적해석을 이용한 억지말뚝의 사면안정 내진보강 효과 연구)

  • Han, Jin-Tae;Cho, Jong-Suck;Yoo, Min-Taek;Lee, Seung-Hyun
    • Journal of the Korean Society of Hazard Mitigation
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    • v.11 no.2
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    • pp.93-101
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    • 2011
  • Korea has about 70% of its land classified as the mountain area, which has led to cut-slope being the result of substantial road and railway construction. However, there is currently a lack of research about the seismic retrofit design of a slope, even though many earthquakes have recently occurred at home and abroad. In this study, in order to investigate the stabilizing effect of piles against sliding during an earthquake, a series of 1 g shaking table tests and pseudo-static analyses were carried out. As a result, the stabilizing effect of piles against sliding during an earthquake was verified by the 1 g shaking table tests and the most effective result from the pseudo-static analyses was that the installation of the piles on the central part of the slope, where the failure surface included piles unlike the lower part and upper part of the slope. Furthermore, when the pile was installed on the central part of the slope, the change of the safety factor depending on the distance between the center of two piles was evaluated.

A Study on the Analysis of the Fracture Behavior of Pallet Racks due to Earthquake Load (지진하중으로 인한 팔레트 랙의 파괴 거동 분석에 관한 연구)

  • Kim, Chunggil;Heo, Gwanghee;Jeong, Seonghoon;Kim, Sun Tae;Seo, Youngdeuk;Ko, Byeongchan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.2
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    • pp.157-164
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    • 2023
  • This study aims to analyze the damage and destruction behavior of pallet racks due to external forces through shaking table test. Pallet racks is a general storage racks type consisting of column, beam, and brace to resist an external force. To analyze the safety of the pallet racks due to external force, a shaking table test was conducted to investigate the pallet racks behavior due to external force while increasing the seismic load targeting the pallet racks used in the existing logistics storage facility. As a result of the shaking table test, it was confirmed that the torsion of the pallet racks damaged the connection parts of some members located on the 1st and 2nd levels, thereby destroying the loading equipment.

Evaluation of Seismic Performance of Valve Chamber System by Shaking Table Tests (진동대 실험을 통한 밸브실 시스템의 내진성능 평가)

  • Young-Soo Jeong;Kyeong-Seok Lee;Jin-Seok Yu;Hyung-Chae Jeong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.28 no.1
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    • pp.46-52
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    • 2024
  • The structural safety of expansion joints for piping systems has been drawing attention owing to ruptures and leaks of water pipes caused by earthquakes and road subsidence at soft ground. In general, metal bellows are installed as expansion joints to prevent various damages in the piping system. In this study, the seismic performance of a valve chamber system was evaluated by performing earthquake shaking table tests. To validate the benefits to structural safety of metal bellows in connecting steel pipes to valve chambers, the seismic tests were conducted on expansion joints (bellows) and general pipping, and the results were compared for durability. Strain gauges were attached to measure the effects of the input motion. As a result of the shaking table test, it was confirmed that the strain of the valve chamber structure and inflow or outflow steel pipes were decreased in 1/100, 1/20 by applied to the expansion joints.

Design Parameter Identification Using Transfer Function of Liquid Column Vibration Absorber (LCVA) (전달함수를 이용한 LCVA의 설계변수 분석)

  • Lee, Sung-Kyung;Min, Kyung-Won;Chung, Hee-San
    • Journal of the Earthquake Engineering Society of Korea
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    • v.13 no.4
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    • pp.47-55
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    • 2009
  • The purpose of this study is to verify the transfer function of input acceleration and output control force by linearizing a velocity-dependent damping term of Liquid Column Vibration Absorber (LCVA). Analytical and experimental research is conducted to identify natural frequency, damping ratio and participated mass ratio of LCVA with various section ratios of vertical and horizontal areas. Findings obtained experimentally by the shaking table test are compared with analytical findings using optimization technique with constraints. The results indicate that the level of liquid and section ratio of LCVA affect the characteristics of damping ratio and mass ratio. Damping and mass ratio increase as the section of vertical column of LCVA decreases, due to turbulence in the elbow of LCVA.

Applicability of Similitude Laws for 1-g Shaking Table Tests (1-g 진동대 모형시험을 위한 상사법칙의 적용성 평가)

  • 황재익;김성렬;김명모
    • Journal of the Korean Geotechnical Society
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    • v.20 no.3
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    • pp.141-150
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    • 2004
  • Shaking table model tests were performed to reproduce the dynamic behavior of a gravity quay wall and a pile-supported wharf which were damaged during the Kobe earthquake in 1995. The results of the model tests were compared with field measurements and with the results of previous model tests. The displacements of the model quay wall were only one third of that of the prototype, whereas the deformation state of the model was similar to that of the prototype. The displacements of the model pile-supported wharf were about two thirds of that of the prototype and the locations of the maximum moments at the model pile were similar to the buckling locations of the prototype piles.