• 한국안전학회지
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• 제20권3호
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• pp.126-133
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• 2005

Behavior of saw-dust concrete has not studied because many people have thought that saw-dust concrete cannot be applicable for structural member, up to now. This study is to findout how much the concrete can be structurally applicated. 5mm grid sieve was used to select satisfactory sawdust for better concrete quality. Test molds size of ${\phi}10{\times}20cm$ long were made of normal without sawdust, 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8% 2.0%, for making concrete strengh of 180kg, 210kg, 240kg, 270kg which they are normally used in practice presently. A various strengths tests such as compressive splitting tensile, flexible strength behavior of structural member named beam using size of $20{\times}30{\times}120cm$ have been done for the structural aspects. Tensile strength shows that it can be more affected than higher strength of it.

• 한국터널지하공간학회 논문집
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• 제17권6호
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• pp.695-702
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• 2015

원심모형시험은 최근의 기계적, 이론적 발전에 따라 그 활용도와 정확성이 높아지고 있다. 원심모형시험은 원지반 응력을 효과적으로 재현할 수 있으므로 주위 지반 또는 암반과 상호작용을 하는 터널과 같은 지하구조물의 거동을 모사하기 적합하다. 본 연구에서는 병렬 터널의 지진시 동적 거동을 원심모형시험을 통하여 분석하였다. 터널 모델링시 지진에 의해 발생하는 최대 가속도 저감을 위하여 Flexible segment를 고려하였으며 Flexible segment의 두께가 얇은 경우와 두꺼운 경우를 각각 고려하였다. 시험 결과 Flexible segment의 지진시 터널 구조물에 발생하는 최대 가속도 저감 효과를 확인하였다. 그러나 Flexible segment가 얇은 경우 단주기파 적용시 최대가속도의 저감효과는 없었고, 두꺼운 경우 기반암 가속도가 클 경우 보다 효과적임을 확인하였다. 또한 동일 모델에 대하여 3차원 수치해석을 수행하여 지진시 거동을 파악한 결과, 시험 결과와 유사한 경향을 보임을 확인할 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1526-1531
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• 2008

The objective of this study is to evaluate the loading capacity of lattice girder according to loading position. 3-point flexible strength tests were performed on three types of lattice girder, such as LG-$50{\times}20{\times}30$, LG-$70{\times}20{\times}30$, and LG-$95{\times}22{\times}32$, mainly used in Korea. Two types of loading position for each flexible strength test were used to analyze the behavior of load-deformation. In 3-point flexible strength test, the difference of the average of maximum flexible strength according to loading position had the range from 10% to 33%.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.287-294
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• 2002

Underground flexible pipes for electric cables are subject to external loads and surrounding soil pressure. Particularly, strain of flexible pipes is of great concern in terms of safety and maintenance for electric cables. In this study, the actual size tests were carried out to investigate strain-deformation relation for underground flexible pipes subject to vehicle loads with various depths and degree of compaction.

• Geomechanics and Engineering
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• 제9권2호
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• pp.243-259
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• 2015

Comparative study has been performed to investigate the behavior of dredged fills on rigid (Model 1) and flexible (Model 2) containers. The study was focused on the sedimentation of soil fills and the development of total stresses. Model 1 is made of an acrylic cylinder and Model two is a scale-size geotextile tube. Results indicate that for rigid containers, significant decrease of the sediment height is apparent during the dewatering process. On the other hand, because the geotextile is permeable, the water is gradually dissipated during the filling process on flexible containers. Hence, significant loss in the tube height is not apparent during the duration of the test. Pressure spikes are apparent on rigid containers during the filling process which can be attributed to the confining effect due to hydrostatic pressure. For the flexible containers, the pressure readings gradually increases with time during the filling process and normalize at the end on the filling stage. No pressure spikes were apparent due to the gradual dissipation of pore water pressure.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.105-112
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• 1999

In recent the superior economic benefits and the convenience of installation increased the use of geosynthetics, especially geogrids with the effects of high tensile strength. In this study, various tests were conducted to determine the physical and chemical properties of geogrids which contains durability under various critical conditions, creep behavior and the stability for installation damage in fields. With analysis of test results, the partial and total safety factors were determined and presented the long term design strength of flexible geogrids.

• 한국항공우주학회지
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• 제36권8호
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• pp.734-739
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• 2008

본 논문에서는 미시 및 중시 역학의 2-단계 해석 전략을 채택하여 유연직물 복합재료의 기계적 거동을 예측하였다. 미시역학에서는 섬유다발의 유효물성치를 계산하였고 그 결과를 이용해 중시역학에서 유연직물복합재료의 인장탄성계수를 예측하였다. 중시역학 해석 과정에서는 섬유다발의 회전 및 전단 대변형에 의한 기하학적 비선형성을 고려하기 위하여 사용자 정의 부프로그램을 개발하여 ABAQUS 내에 삽입하였다. 해석결과, 인장하중을 받는 유연직물복합재료의 응력-변형률은 비선형 거동을 보였고, 계산된 유효탄성계수는 시험값과 잘 일치하는 것으로 나타났다.

• 한국터널지하공간학회 논문집
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• 제10권4호
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• pp.371-382
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• 2008

본 연구의 목적은 국내터널현장에서 강지보재로 주로 사용되어지고 격자지보재(Lattice Gilder)의 공학적인 성능을 보다 객관적으로 판단하기 위한 실내성능평가기법의 제안에 있다. 본 연구를 위하여 국내에서 격자지보재로 주로 사용되는 $LG-50{\times}20{\times}30$, $LG-70{\times}20{\times}30$, 및 $LG-95{\times}22{\times}32$를 사용하여 3-point 휨강도 실험 및 4-point 휨강도 실험을 수행하였다. 또한, 하중재하위치에 따른 격자지보재의 하중-변위거동을 분석하기 위하여 각각의 실험방법에서 두 가지 하중재하방식을 사용하여 실험을 수행하였다. 각 부재에 스트레인 게이지를 부착하여 각각의 실험방법에 따라 각 부재에 작용하는 하중분포를 분석하였다. 3-point 휨강도 실험에 적용한 두 가지 하중재하방식으로 측정된 평균 최대하중은 $10%{\sim}33%$까지 차이가 나타났으며, 4-point 휨강도 실험에 적용한 두 가지 하중재하방식에 의해 측정된 평균 최대하중은 거의 차이가 없었다. 4-point 휨강도 실험의 평균 최대하중은 3-point 휨강도 실험보다 $13.56%{\sim}31.55%$와 정도 크게 나타났다. 3-point 휨강도 실험은 주강봉에 주로 하중이 집중되는 반면 4-point 휨강도 실험은 각 부재로 비교적 골고루 하중이 작용하는 것으로 나타났다.

• 한국해양공학회지
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• 제27권3호
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• pp.29-35
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• 2013

The exploration areas for maritime resources such as oil and natural gas have gradually moved to deep sea areas. It has become difficult to use existing fixed marine structures, which are very costly to build, because that have reached the uppermost economic limit. Therefore, floating marine structures and flexible marine structures are preferred. In particular, slender bodies such as risers and pipes are important parts of ocean depth marine structures. These slender bodies have more flexible structural characteristics in deep water areas because their overall length becomes longer and thediameter/length slenderness ratio gets smaller. In addition, the dynamic behavior of slender bodies becomes complicated as external forces such as tides and waves act on it directly. In this study, in order to solve these problems, we performed model tests in a 2-D wave basin using flexible slender bodies with different modulus of elasticity values. As a result, we compiled statistics and compared the behaviors of flexible slender bodies with respect to the effect of the modulus of elasticity. We expect that the results could be used as reference data for the design of structures with flexible elements.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1207-1212
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• 2009

The flexible multibody dynamic model of an EMS-type Maglev vehicle is necessary in design stage to predict its behavior, load history and levitation performance. Especially in EMS-type Maglev vehicle, the body flexibility of its bogie with electromagnets affects the levitation performance because its feedback control system is more sensitive to vibration of bogie structure. The flexible multibody dynamic model of a 1/2 Maglev vehicle under test is presented. The basic modeling procedure is almost the same as in other applications. However, the feedback control system model unique in EMS-type maglev vehicle must be included in the model. With the model proposed in this study, the dynamic behavior, load history and levitation performance are more precisely predicted. This model could realize the virtual prototyping in EMS-type Maglev vehicle area.