• Steel and Composite Structures
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• 제21권5호
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• pp.1105-1119
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• 2016

In this study, it is presented that a new developed approach for equivalent area-distributed loading (EADL) induced from a single concentrated force. For the purpose, a full scale 3D steel formwork system was constructed in laboratory conditions. A developed load transmission platform was put on the formwork system and loaded step by step on the mass center. After each load increment, displacement was measured in several crictical points of the system. The developed platform which was put in to slab of formwork to equivalently distribute the load from a point to the whole slab was constituted using I profiles. A 3D finite element model of the formwork system was analyzed to compare numerical displacement results with experimental ones. In experimental tests,difference among the displacements obtained from reference numerical model (model applied EADL) and main numerical model (model applied single load using a load cell via load transmission platform) is about %13 in avarage. Difference among the displacements obtained from experimental results and main numerical model under 30 kN single load is about %11 in avarage. The results revealed that the displacements obtained experimentally and numerically are dramatically closed to each other. It is highlighted from the study that the developed approach is reliable and useful to get EDL.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.385-392
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• 2008

Modern city have had a lot of high-rise building in high standards and multi-level performance. Using of city space reach better stages by using integration. These skyscraper have increased working load on ground. that building is efficiently designed for that soil capacity is well applied. With material side, big size pile, high strength concrete and high strength steel is used for that getting enough lobby space and resisting load increased of high-rise building. limit load test and load transmitted test can make soil capacity optimized. By the way, method of measuring pile capacity is more advanced and bigger. pile type applied by high rise building have underground excavation space, also reflect regional soil property and have some fact reviewed. A lot of high rise building recently is built as land mark in Seoul, Busan and Incheon. about method of measuring capacity of foundation pile, example of construction field is compared and reviewed.

• 한국안전학회지
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• 제32권5호
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• pp.8-12
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• 2017

Bicycles are very popular sporting goods in these days. Thus, the durability of bicycles is very important for the safety of bicyclists. It is well known that a bicycle frame is a major component which is essential to the safety and performance of a complete bicycle. In this study, the durability of bicycle frames were experimentally investigated under the fatigue load. Eighty bicycle frames with different types and materials were prepared and tested according to EN standards. Three kinds of fatigue loads, that is, pedalling, vertical and horizontal fatigue load, which occur constantly during riding a bicycle, were applied to the bicycle frames. The experimental results show that the horizontal fatigue load was the severest mode to pass EN standard. The pass ratio of horizontal fatigue load test was 45.2%, while the pass ratio of vertical fatigue load test was 100%. Most of cracks were found at the right side of bottom bracket shell and at the intersection area between head tube and down tube. It seems that the experimental results can be applied to improve the safety and performance of a bicycle frame.

• 재활복지공학회논문지
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• 제9권3호
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• pp.231-236
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• 2015

본 연구에서는 재활운동기기에 적합한 운동부하 조절이 가능한 영구자석형 비 접촉식 원형 브라켓 맴돌이 전류 부하 제동장치를 제안하고 성능을 실험적으로 평가하였다. 제안한 원형 부하 제동장치의 토크 값은 고정 부하를 갖는 "ㄷ"형 부하 제동장치에 비해 49%의 제동력으로 평가되었지만 도전율 변화와 공극의 간격 변화로 다양한 부하 조절이 가능함을 확인하였다. 본 연구에서 제안된 부하 제동장치는 사용자의 상태에 따라 부하 조절이 가능하며 운동기기의 소형화 및 원가 절감 등의 장점을 갖는 운동기기 적용이 가능할 것으로 기대된다.

• 한국지반공학회지:지반
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• 제12권6호
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• pp.51-64
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• 1996

축하중계측장치가 부착된 모형 개단 강관 말뚝을 상대밀도 49%인 초세립질 포화 모래지반을 담고 있는 압력 토조속에 타입한 후 정적압축재하시험을 실시하여 극한지지력을 결정하였다. 극한지지력의 임의 수준의 압축하중을 말뚝머리에 재재하한 후 유사지진 진동 및 Sine정현파 진동을 작용시켜 동적 진동에 의한 개단말뚝의 압축지지력 저감특성을 연구하였다. 유사화된 지진진 동과 Sine정현파진동에 의한 개단말뚝의 지지력 저감특성은 큰 차이를 보였다. 유사화된 지진 진동중 지지력 저감율은 작용하중의 크기에 따라 크게 달라지는데, 작용하중의 크기가 약 70% 이하일 경우에는 지지력 감소율이 8%이하였으며, 극한하중의 90%이상을 지지하는 개단말뚝의 극한지 지력은 약 15%이상 감소되었다. 또한, 외주면 마찰력 성분의 감소량은 감소된 총 지지력의 약 80%를 차지하였다. Sine정현파 진동중 지지력의 감소율은 작용하중의 크기에 따라 달라지지 않으며, 진폭과 진동수에 의해 크게 영향을 받았다. 즉, 진폭이 클수록, 진동수가 적을수록 지지력은 크게 감소되었다. 관내토 폐색응력의 감소양상은 진동의 종류에 따라 크게 달랐다. 유사 지진 진동에 의한 관내토 폐색응력의 감소는 작용하중의 크기에 상관없이 말뚝 선단으로 부터 약 3.0D, 이내의 관내 토에서 발생되었다. Sine정현파 진동에 의한 판내토 폐색응력의 감소는 말뚝 선단으로 부터 약 1.0D,이내의 관내토에서 크게 감소하고, 1.0-3.0D,의 관내토 부분에서는 거의 감소되지 않았다. 또한, 관내토 폐색력은 크게 감소되어졌고, 작용하중의 크기에 따라 감소율도 크게 달랐다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1631-1635
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• 2011

To consider dynamic magnification effect at the static design stage, impact load factor is applied to design load. Current impact load factor adopted EUROCODE without verification while Japan suggested impact load factor including velocity of high-speed train throughout theoretical and experimental studies. On the purpose of evaluate current impact load factor, this study investigated the calculation of impact load factor from dynamic response of running train.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.339-342
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• 2000

Repetitive Load Prediction is proposed for the UPS inverter application of the second order deadbeat controller which is robust against the calculation time delay and the parameter variation and which gets fast response against the load variation. The proposed technique predicts the load current ahead of two sampling time using that the load current is periodic. This is effective under nonlinear load condition. The proposed technique is derived theoretically and verified through simulation and experimental result.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.590-591
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• 2011

This paper proposes a short-term load forecasting by using a temperature and load pattern. The forecasting model that represents the relations between load and temperature which get a numeral expected temperature based on the past temperature was constructed. Case studies were applied to load forecasting for 2009 data, and the results show its appropriate accuracy.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2487-2492
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• 2011

At high rail temperature above the neutral temperature, high compressive axial stresses will occur in the rails. High thermal axial force and vehicle loads cause the track to shift in a lateral direction and the formation of track geometry imperfections (track irregularity). When the thermal stress level and track irregularity with vehicle load reach a critical value, the track loses stability. In many studies, the stability of CWR tracks is analyzed. However these studies are only considered in temperature load. The main objective of this investigation was to estimate a new, comprehensive, realistic, the stability of CWR tracks considering wheel load. The ballast resistance is changed by wheel load. When the wheel load is applied, rails and ties are moved upward or downward. In this case the friction between ties and ballasts is decreased or increased. In this study the change of the ballast resistance of each tie was applied to the nonlinear analysis of CWR tracks.

• International Journal of Precision Engineering and Manufacturing
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• 제2권2호
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• pp.5-10
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• 2001

This paper attempt to explore the shape of stress wave propagation of 3-dimensional stress field which in made in the process of the time increment. A finite element program about 3-dimensional stress wave propagation is developed for investigating the changing shape of the stress by the impact load. The finite element program, which is the solution for the 3-dimensional stress wave analysis, based on Galerkin and Newmark-${\beta}$ method at time increment step. The tensile stress and compressive stress become larger with the order of the middle , the upper and the opposite layers when the impact load is applied. In a while the shear stress become larger according to the order of the upper, the middle and the opposite layers when impact load applied.