• Journal of the Korean GEO-environmental Society
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• v.8 no.6
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• pp.61-68
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• 2007

The problem on cyclic plate load tests was analyzed by finite element method using an anisotropic hardening constitutive model. The constitutive model was coded to user subroutine in ABAQUS. Using the result of the analysis, Young's moduli corresponding to various strain levels were evaluated by a back calculation method and were very similar to those of input. On the basis of the back calculation method plate loading tests were verified. As a result, deformation moduli could be evaluated practically from cyclic plate load tests with respect site conditions.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.161-168
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• 2003

평판재하시험은 재하시험시 표층의 매우 잘 다져진 곳에 대한 지지력 계수를 획득하여 실다짐도를 과대 평가하는 결과를 초래할 수 있다. 이에 착안하여 응력도달 범위가 작은 평판재하시험을 지양하고 콘관입시험으로부터 획득되는 노상의 관입지수로부터 지반의 다짐도를 추정할 수 있는 콘관입시험기와 구동시스템 및 해석 프로그램을 개발하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.666-669
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• 2011

The rupture disc shapes of bulkhead type pulse separation device(PSD) are designed for new dual pulse rocket motor. Before final design PSD, that three different rupture disc are tested and confirmed the performance of the discs. Through analyzing the test results the PSD decides, two rupture disc shapes with flow holes of eight circles and eight trapezoids.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.6
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• pp.134-141
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• 2018

In this paper, the possibility of using an MDF (Mild-detonating Fuse) as a linear separation device is studied. An MDF is a small diameter metal (lead) tube filled with explosives (RDX). Aluminum plate cutting experiments are carried out with different values of target plate thickness and explosives per unit length. Based on the experimental results, a numerical analysis method including the failure criteria is established. The mechanism and characteristics of using MDFs for aluminum plate cutting are identified; the possibility of using the current system as a linear separation device is verified. By utilizing a developed numerical method, the separation reliability for diverse structures and MDFs can be predicted in advance and the number of experiments required for development can be minimized.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.37-47
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• 2005

The purpose of this study is to estimate the bearing capacity and settlement characteristics of the weathered granite masses, and on the process to achieve the purpose, in the first place, the weathered degree according to the absorption index was examined and reviewed, then plate bearings test in in-situ depth were tested, and finally the result was compared and examined with the result of the existing, estimate method and pressuremeter test. In order to achieve the purpose of this study, a typical area distributed with weathered granite masses, gyeonggi area, was chosen as a sample site for testing, and in the result, it appeared and found out that the more the weathered degree increases when the plate bearing test are tested, the more the bearing capacity decreases a numerical indexes and the more greatly the width of the decrease of bearing capacity increases around the boundary of specific, weathered degrees. Also, In the result from estimating the bearing capacity of weathered granite masses by the existing, suggested formula, it appeared that there is a tendency that the more the weathered degree increases, the more similar the bearing capacity becomes with the result of plate bearing tests.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.636-643
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• 2008

The objective of this paper is to assess the potential use of the geogauge and the light falling weight deflectometer (LFWD) and the soil impact hammer as quality control/quality assurance $Q_C/Q_A$ devices for compacted soil layers. A comprehensive field experimental program considering variation of number of compaction, water contents and thickness of compaction layer was conducted on compacted layers of gravel sand. The geogauge, LFWD, the soil impact hammer and static load test (PLT) as a reference test were performed for the compacted layers. The geogauge elastic modulus, $E_G$, the LFWD dynamic modulus, ELFWD, empirical soil stiffness, $K_{30}$, obtained from soil impact hammer and soil stiffness directly obtained from PLT, $K_{30}$, were correlated with increasing number of compaction. The results of this study show that the geogauge, LFWD and the soil impact hammer, which are very simple to test, can be used as substituting devices for static PLT which is a conventional quality control/quality assurance $Q_C/Q_A$ devices for compacted soil layers.

• Journal of the Korean Geophysical Society
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• v.4 no.4
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• pp.287-296
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• 2001

국내 건설현장에서는 성토다짐의 다짐도 확인을 위해 주로 평판재하시험(PBT)을 사용한다. 평판재하시험은 재하시험시 표층의 매우 잘 다져진 곳에 대한 지지력 계수를 획득 하여 실다짐도를 과대 평가하는 결과를 초래할 수 있다. 이에 착안하여 응력도달 범위가 작은 평판재하시험을 지양하고 콘관입시험으로부터 획득되는 노상의 관입지수로부터 지반의 다짐도를 추정할 수 있는 콘관입시험기와 구동시스템 및 해석 프로그램을 개발하였다. 개발된 시스템은 다짐차량에 간편하게 부착하여 현장에서 직접 다짐도를 획득할 수 있으며 다짐도와 더불어 다져진 지반의 전단강도정수를 동시에 측정할 수 있다.

• The Journal of Engineering Research
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• v.5 no.1
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• pp.109-118
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• 2004

국내 건설현장에서는 성토다짐의 다짐도 확인을 위해 주로 평판재하시험(PBT)을 사용한다. 평판재하시험은 재하시험시 표층의 매우 잘 다져진 곳에 대한 지지력 계수를 획득하여 실다짐도를 과대 평가하는 결과를 초래할 수 있다. 이에 착안하여 응력도달 범위가 작은 평판재하시험을 지양하고 콘관입시험으로부터 획득되는 노상의 관입지수로부터 지반의 다짐도를 추정할 수 있는 콘관입시험기와 구동시스템 및 해석 프로그램을 개발하였다. 개발된 시스템은 다짐차량에 간편하게 부착하여 현장에서 직접 다짐도를 획득할 수 있으며 다짐도와 더불어 다져진 지반의 전단강도정수를 동시에 측정할 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2146-2150
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• 2008

본 연구에서는 용기포항 동방파제 건설이 사곶 수욕장에 미치는 영향을 평판재하시험, 토질분석시험, 위성사진 자료 분석, 파랑, 조류, 수심 등의 현장관측과 파랑, 파랑류, 조류, 그리고 퇴적물 이동 등에 대한 수치모형을 통하여 사곶해수욕장의 동역학적 특성을 파악하였다. 평판재하시험과 토질분석시험 결과 기존의 사곶해수욕장 지역의 지지력 변화는 거의 없는 것으로 나타났으며, 방파제 건설로 인해 퇴적이 진행 중인 지역은 상대적으로 지지력이 낮게 나타났다. 현장관측으로 수집된 파랑, 조류, 수심의 자료는 수치모형의 입력 값으로 사용되었으며, 파랑류 수치모형결과 사곶 해수욕장 부근에서 파향에 따라 약한 소규모 와류가 발생하였으며, 퇴적물이동 수치모형의 경우 국소 와류에 의한 지형변화가 발생하였으며, 남서와 북동에 약간의 퇴적이 발생하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.3
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• pp.53-61
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• 1999

Impinging jets are observed when exhaust gases from missiles or V/STOL aircrafts impinge on the ground, flame deflector, ship deck, etc. The flow shows different patterns according to the nozzle geometry, nozzle-to-plate distance, and plate angle, for example. This paper describes experimental works on the phenomena (pressure distribution, occurrence of stagnation bubble, and so on.) when underexpanded supersonic jets impinge on a perpendicular flat plate using a supersonic cold-flow system, and compares the results with those obtained using a shock tunnel. The flow characteristics for the supersonic cold-flow system were also investigated. Surface pressure distribution of supersonic cold-flow system differed from that of shock tunnel because of water and temperature in the low-pressure chamber. Surface pressure distribution as to underexpanded ratio showed similar patterns together.