• Computational Structural Engineering
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• v.6 no.1
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• pp.39-43
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• 1993

본문에 열거한 빙하중의 산정방법을 비교해 볼 때, 구조물의 규모가 크고 다년생 얼음이 설계하중으로 작용하는 경우 에너지 평형 방법 중 소성 극한이론을 근거로 한 Korzhavin식을 이용하는 것이 타당하리라 판단된다. 극한 응력에 의한 방법은 구조물의 직경이 작은 경우에 완전 관입이 되는 것을 가정하기 때문에 직경이 큰 구조물에서는 빙하중의 크기가 과대 평가될 가능성이 크며, 극한 하중에 의한 방법은 Ridge Building Force의 부정확성 때문에 쉽게 적용하기 곤란하여 이에 대한 통계적 자료가 크게 요구된다. 지반과 구조물의 유연성을 고려한 동적 모델에 의한 방법은 참고문헌을 소개하는 것으로 대신한다.

• Journal of the KSME
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• v.49 no.12
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• pp.54-59
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• 2009

자동차 부품 등 내구재의 파손은 긴 시간 동안 누적된 비교적 크기가 작고 빈도가 많은 입력하중에 기인하거나 상대적으로 적은 수의 큰 입력하중에 의해 유발된다. 미션 프로파일화(Mission Profiling)와 미션 합성(Mission Synthesis)은 어느 시험실에서나 공통된 장비를 이용하여 실제 환경에서 제품이 받는 동일한 수준의 피로 손상도를 보장하면서 훨씬 단축된 시험을 구현할 수 있는 시험 규격을 만들어 내는 과정이다. 이 글에서는 최신의 기술을 이용하여 이와 같은 가속화 진동내구 시험의 목적을 이루는 것에 관해서 소개한다.

• Journal of the KSME
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• v.30 no.2
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• pp.131-140
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• 1990

손상 허용 설계 개념의 목적은 항공기 성능의 최대 관건이 구조물 무게가 과도하게 증가하는 것 을 방지하고 동시에 충분한 신뢰도를 만족시키는데 있다. 이러한 테크놀로지의 설계 적용에 대하 여 몇 가지 중요한 점을 지적하면 결함 검사를 위하여 외부에서 접근이 용이하게 설계되어야 하 고 단일 하중 전달 구조에 비하여 다중 하중 전달 구조가 바람직한 것이다. 또한 해석적 방법에 대하여 충분한 시험으로 해석과정의 유효성이 인정되어야 하며 일반적으로 전체 구조의 수명을 위하여 재료의 인성치를 증가시키는 것보다 균열 검출 기술을 향상시켜 검출 가능 결함 크기를 낮추는 것이 효과적이라 할 수 있다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1986.11a
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• pp.47-51
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• 1986

로울러 베어링의 로울러는 길이방향으로 적당하게 Profiling하여 양단부에서 발생하는 응력집중을 줄이고 있다. 로울러와 레이스간의 접촉을 단순한 탄성접촉문제로 해석하는 경우에는 유막의 개념이 없어서 로울러와 레이스 사이의 압력분포와 유막형상을 정확하게 나타내기가 어려우므로 탄성변형과 압력에 따른 윤활유의 점도 변화를 고려한 탄성유체윤활(EHL)해석이 필요하다. 대부분의 해석은 무한장 로울러로 취급하는 것이 보통이며 실제의 로울러에 해당하는 유한한 길이의 선접촉 EHL 해석은 Mostofi & Gohar 및 Kuroda & Arai의 해석 정도이나 각각은 수렴하중이 작거나 로울러의 길이가 아주 짧은 경우에 해당한다. 본 연구에서는 FDM과 Newton-Raphson method를 이용하여 길이가 유한한 실제 크기의 Profiled 로울러에 대한 EHL상태에서의 압력분포와 유막형상을 보다 하중이 온 경우에 대해서 구하고자 한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.3
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• pp.1-7
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• 2003

Excitation and system identification are carried out for a full-scale five-story structure to obtain fundamental data which will be used for the design of viscoelastic dampers, The hybrid mass driver(HMD) installed on the fifth floor was employed as external exciter to provide excitation for the building, Each floor response was measured and processed to find out where and how the viscoelastic dampers are located and designed. The sine-sweep and white noise loadings were applied to the structure by the HMD to obtain dynamic characteristics such as natural frequencies, damping ratios, and modes, The identified building was experimentally investigated again with the designed viscoelastic dampers installed at inter-stories to obtain the response behavior in the companion paper.

• Geotechnical Engineering
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• v.11 no.2
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• pp.19-28
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• 1995

Based on the various test data acquired in the field, the large pressure chamber and the small pressure chamber, uplift behaviors and method of determining the ultimate uplift capacity of pile driven in small pressure chamber were studied. After uplift pile experienced 2 or 3 sudden slip due to increase of uplift load, complete pullout failure was occurred. Thus, it appears that the ultimate uplift capacity could be identified as the load at displacement where first slip occurs. The ultimate uplift capacity might be determined in every test and the disturbance after first uplift test could be recovered by adding one blow of the drop hammer, which had to depend on the model pile capacity.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.37-46
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• 2001

Pile load tests were carried out to investigate the contribution of the pile cap to the carrying capacity of a pile group and load transfer characteristics of piles in the group. A group of 24 piles$(4 \times6 array)$ of 92.5mm diameter steel pipe were installed to the depth of 3m fron the ground surface, the top of weathered rock. A maximum load of 320ton was applied to the pile cap, $1.5\times2.3m$, in contact with the ground surface. At the maximum load of 320ton, the pile cap has carried 22% of the total load. Average ultimate capacity of pile in the pile group was estimated to be 16.4ton, substantially higher than that of single pile, installed at the corner and tested before pile cap construction. For the same magnitude of settlement, the pile in the center carried less load than the pile at the perimeter due to strain superposition effect. Piles in the group showed almost constant contribution(approx. 60%) of side friction to the total capacity for all of the loading stages, while that of single pile decreased from 82% to 65%.

• Journal of Korean Society of Steel Construction
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• v.25 no.5
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• pp.487-495
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• 2013

As the first step to suggest effective ways of using direct analysis method considering current situations of construction fields in Korea, analytical approach is used to verify direct analysis method which adapts initial imperfection limitation of Korean specification of building construction. The main analytical variables are size of frames, axial load ratio, axial load distribution, value of notional loads, location of notional loads, and applied method of notional loads. The results show that the use of initial imperfection limitation of Korean specification, L/700 is suitable, and the recommendable method to use direct analysis method is applied notional loads based on L/700 as minimum lateral load at each story, even if B2 is less than 1.5 and lateral loads exist.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2212-2218
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• 2015

In order to find out the load bearing behavior of sand and clay which sustain three types of shallow footing, finite element analyses were performed. Failure zone of sand which sustain strip footing was affected by relative density of sand whereas, failure zone of clay was not affected by soil strength and it was similar to the failure zone which is considered in theory. Considering the shape of load-settlement curves obtained by numerical analyses, punching shear failure can be seen in loose sand and ultimate bearing load can not be seen in dense sand whereas, yielding point can be seen in clay. Ultimate bearing loads for sand predicted by theory were greater than those obtained by numerical analyses and ultimate bearing loads for clay predicted by theory were similar to those of numerical analyses. Ultimate bearing loads determined by 1 inch settlement criteria were slightly less than those of numerical analyses.

• Journal of Korean Society of Steel Construction
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• v.26 no.1
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• pp.11-20
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• 2014

The Concrete Capacity Design(CCD) method has been used in the design of anchor since 2001 and Korean design code specify that concrete breakout capacity of CIP anchor under seismic load shall be taken as 75% of static capacity. In this study, an experimental study was performed to evaluate the concrete breakout capacity of unreinforced CIP anchors under dynamic shear force. For the purpose, three static and dynamic shear-loading tests were conducted using 20mm diameter anchors, respectively. The edge distance of 120mm was considered in the tests. In the dynamic tests, 15 cycles pulsating load with 1Hz speed was applied and the magnitude of loading step was increased until concrete breakout failure occurs. From the tests, the concrete breakout capacity under dynamic shear loading showed nearly same capacity by static loading.