• Title/Summary/Keyword: Ground Vibration Test

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Ground Vibration Test for Korea Sounding Rocket - III (KSR-III의 전기체 모달 시험)

  • 우성현;김영기;이동우;문남진;김홍배
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.441-447
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    • 2002
  • KSR-III(Korea Sounding Rocket - III), which is being developed by Space Technology R&D Division of KARI(Korea Aerospace Research Institute) will be launched in late 2002. It is a three-stage, liquid propellant rocket which can reach 250 km altitude and will carry out observation of ozone layer and scientific experiments, such as microgravity experiment, and atmospheric measurement. KSR-III is believed to be an intermediate to the launch vehicle capable of carrying a satellite to its orbit. Space Test Department of KARI performed GVT(Ground Vibration Test) fer KSR-III EM at Rocket Test Building of KARI. GVT is very important for predicting the behavior of rocket in its operation, developing flight control program and performing aerodynamic analysis. This paper gives an introduction of rocket GVT configuration and information on test procedures, techniques and results of It. In this test. to simulate free-free condition, test object hung in the air laterally by 4 bungee cords specially devised. For the excitation of test object, pure random signal by two electromagnetic shakers was used and total 22 frequency response functions were achieved. Polyreference parameter estimation was performed to identify the modal parameters with MIMO(Multi-Input-Multi-Output) method. As the result of the test, low frequency mode shapes and modal parameters below 60Hz were identified

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Field Tests Investigating the Ground Borne Vibration Induced by Underground Railway Tunnel (터널 내 열차주행으로 인한 지반진동 현장측정시험)

  • Ahn, Sung-Kwon;Bang, Eun-Seok;Lee, Bae
    • Journal of the Korean Society for Railway
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    • v.13 no.2
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    • pp.208-213
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    • 2010
  • This paper describes the instruments used, and the test procedures adopted, and the findings obtained from a research project aiming to investigate, via full-scale field tests, the ground borne vibration caused by underground railway tunnel constructed in hard rock. The ground borne vibration induced by high-speed trains (i.e. the Korea Train eXpress (KTX) services) with a speed of approximately 200km/hr was measured inside the borehole constructed in the close proximity to the KTX tunnel using 3-component borehole seismographs in order to investigate the wave propagation of ground borne vibration. This paper also discusses the limitation associated with the current practice of measuring ground borne vibration using conventional borehole seismograph.

Design and Ground Test of Gust Generator for GLA Wind Tunnel Test (돌풍하중완화 풍동시험을 위한 돌풍발생장치 설계 및 지상시험)

  • Lee, Sang-Wook;Kim, Tae-Uk;Kim, Sung-Chan;Hwang, In-Hee;Ha, Chul-Keun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11b
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    • pp.45-48
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    • 2005
  • Tile gust generator was designed for generating the gust field in the wind tunnel test of the scaled flexible wing model for validating gust response alleviation system. The ground operation test was performed for estimating the dynamic performance of tile gust generator before installing it in the wind tunnel for gust field measurement. The ground test results showed that the gust generator has sufficient dynamic capability to simulate the sinusoidal and random motion of the gust generator wing and thus can be used in the wind tunnel test related to gust.

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Computation of Unsteady Aerodynamic Forces in the Time Domain for GVT-based Ground Flutter Test (지상 플러터 실험을 위한 시간 영역에서의 비정상 공기력 계산)

  • Lee, Juyeon;Kim, Jonghwan;Bae, Jaesung
    • Journal of Aerospace System Engineering
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    • v.10 no.1
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    • pp.29-34
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    • 2016
  • Flutter wind-tunnel test is an expensive and complicated process. Also, the test model may has discrepancy in the structural characteristics when compared to those of the real model. "Dry Wind-Tunnel" (DWT) is an innovative testing system which consists of the ground vibration test (GVT) hardware system and software which computationally can be operated and feedback in real-time to yield rapidly the unsteady aerodynamic forces. In this paper, we study on the aerodynamic forces of DWT system to feedback in time domain. The aerodynamic forces in the reduced-frequency domain are approximated by Minimum-state approximation. And we present a state-space equation of the aerodynamic forces. With the two simulation model, we compare the results of the flutter analysis.

Ground Vibration Test for Korea Sounding Rocket - II PFM (과학로켓 2호(KSR-II) 준비행 모델의 지상 진동 시험)

  • 우성현;김홍배;문상무;이상설;문남진
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.546-551
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    • 2001
  • Space Test Department at KARI(Korea Aerospace Research Institute) plans to carry out the GVT(Ground Vibration Test) for the KSR(Korea Sounding Rocket)-III FM(Flight Model) which is being developed by Space Technology R&D Division. KSR-III will be an intermediate to the launch vehicle capable of carrying satellites to their orbits. GVT offers very important information to predict the behavior of KSR in its operation, and to develop the flight control and aerodynamic analysis. For development of test facilities, testing and analysis methods which can be used for the future test, Space Test Department has performed the GVT with KSR-II PFM(Proto-Flight Model) at Satellite Integration & Test Center of KARl This paper discusses the procedures, techniques and the results of it. In this test, to simulate free-free condition, test object hung in the air by 4 bungee cords specially devised. The GVT was carried out using pure random excitation technique with MIMO(Multi-Input-Multi-Output) method with three electromagnetic shakers, and poly-reference parameter estimation was used to identify the modal parameters. As the result of the test, 11 mode shapes and modal parameters below 200㎐ were identified and compared with analytical results.

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Ground Vibration Test of KF- 16D (KF-16D 지상진동시험)

  • Byun, Kwan-Hwa;Park, Chan-Yik;Kim, Jong-Heon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.5
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    • pp.41-49
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    • 2005
  • This paper discusses the test procedure, instrumentation, verification methodology and the results of the ground vibration test(GVT) performed on the KF-16D aircraft to estimate experimentally dynamic characteristics of the aircraft. The modal tests for 7 external store configurations were conducted to estimate effects of external stores on the aircraft vibration modes. To emulate free-free boundary conditions the test aircraft was mounted on its landing gear structure with deflated tires during the GVT. The airframe modal tests were done by burst random excitations with 6 to 8 shakers and about 200 accelerometers. Frequency response functions(FRFs) were measured for each test, and the FRFs were reduced and analyzed to identify the dynamic parameters interested. The analyses were carried out in two steps. To extract modal parameters such as, frequencies and damping ratios, the poly-reference least square complex exponential method was used in the time domain. The mode shape coefficients were estimated with the least squares frequency domain method to identify the vibration modes.

A Case Study of Analysis and Evaluation of Vibration by Construction of Cast in Place Concrete Pile in the Neighboring Areas of Heunginjimun (흥인지문 인접 CIP공사시 진동 전달 특성 분석 및 평가 사례 연구)

  • Choi, Jae-Sung;Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.9
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    • pp.870-878
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    • 2012
  • This paper analysed the effect on Heunginjimun of ground vibrations due to C.I.P. works during Heunginjimun restoration period. Vibration criteria and laws for historic structures was investigated. The vibration was measured under test construction in the field, analysed and evaluated. Because the ground vibration exceeded the vibration criteria, the restoration construction could not be go along. But as vibration was transferred to the upper structures, it was confirmed that vibration levels declined, because of differences between natural and forced frequencies. If the natural frequencies database of historic structures are established, it will help with management and preservation of cultural properties by an environmental vibration effects evaluation.

Ground-born vibration at multileveled train tunnel crossing

  • Moon, Hoon-Ki;Kim, Kang-Hyun;Kim, Ho-Jong;Shin, Jong-Ho
    • Structural Engineering and Mechanics
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    • v.73 no.4
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    • pp.367-379
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    • 2020
  • In recent railway projects where the railway connects between cities, newly planned tunnels are often located close to, or beneath an existing tunnel. Many claims and petitions have voiced public concern about the vibration and noise resulting from the situation. Vibrations and noises are engineering issues as well as environmental problems, and have become more important as people have become more concerned with their the quality of life. However, it is unlikely that the effects of vibration in situations where trains simultaneously pass a multileveled tunnel crossing have been appropriately considered in the phase of planning and design. This study investigates the superposition characteristic of ground-born vibrations from a multileveled tunnel crossing. The results from model tests and numerical analysis show that the ground-born vibration can be amplified by a maximum of about 30% compared to that resulting from the existing single tunnel. Numerical parametric study has also shown that the vibration amplification effect increases as the ground stiffness, the tunnel depth, and the distance between tunnels decrease.

A Study on the Ground Vibration of the Front and the Back Direction of the Free Face in the Bench Blasting (계단식 발파에 있어서 자유면 전.후방의 지반진동에 관한 연구)

  • 기경철;김일중
    • Explosives and Blasting
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    • v.20 no.2
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    • pp.21-31
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    • 2002
  • We did bench blasting upon the natural rock which it's uniaxial compressive strength was about $1,420~1,476kgf/\textrm{cm}^2$. This is the results we inferred after measuring, analyzing the ground vibration velocity of the front and back direction from the free face of the bench blasting. We have to induce the square and cube root scaled equation and the general equation to guarantee confidence upon the data when analyzing the measurement data of the test blasting. The variable distance is in reverse proportion to the permitted ground vibration velocity. The shorter is the exploding point to a protection structure, the bigger is the reflection that the direction of the free face experts the ground vibration velocity, The ground vibration velocity front of the free face tends become reduced about 38~46% compare with back of the free face in the range that the permitted ground vibration velocity is 2.0~5.0mm/sec. In case of 2.0mm/sec, when a protection structure is within about 95m, the max. allowable charge weight per delay on positing front of the free face can be more used about 2.61 times than that on positing back of the free face, in case of 3.0mm/sec within about 78m more about 2.38 times, in case of 5.0mm/sec within 60m more about 2.10 times. In case of 2.0~5.0mm/sec when a protection structure is within about 200m front from the free face, the max. allowable charge weight per delay can become about 1.52 times than the case on back to the free face.

The Ground Vibration Test on an Aircraft and FE Model Update (항공기 지상 진동 시험 및 동특성 모델의 개선)

  • 유홍주;변관화;박금룡
    • Journal of KSNVE
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    • v.8 no.4
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    • pp.690-699
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    • 1998
  • This paper discusses the techniques, procedures and the results of the ground vibration test(GVT) performed on the development aircraft and the simple procedure of FE model updating technique from the GVT results. The GVT was carried out using random excitation technique with MIMO(Multi-Input-Multi-Output) data acquistion method, and taking full advantage of poly-reference global parameter estimation technique to identify the vibration modes. In dynamic FE modeling, the aircraft was represented by beam elements and all dynamic analysis was performed using MSC/NASTRAN for this model. In updating procedure, the stiffness of the beam model was adjusted iteratively so as to get the natural frequencies and mode shapes close to the GVT results.

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