• 한국지반공학회지:지반
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• 제13권6호
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• pp.45-60
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• 1997

본 논문에서는 새로 제안된 외말뚝의 횡하중에 대한 거동과 사면에서의 억지말뚝으로서의 거동에 관하여 연판하였다. 특히 기존의 원형PC말뚝을 대신할 수 있는 새로운 말뚝의 단면을 실험을 통하여 결정하고 이에 대하여 외 말뚝으로서의 수평력에 대한 거동과 사면에서의 안전율 증진 효과를 고찰하였다. 연구 결과 새로운 형태의 말뚝은 외말뚝으로서는 동일한 청하중에 대하여 말뚝의 최대 변위량 이 기존의 원형PC말뚝보다 훨씬 작은 것으로 평가되었으며, 허용변위량에 대한 수평 하중은 증가하였다. 또한 사면에서의 거동을 비교한 결과 동일한 조건에서 안전율이 원형 PC말뚝보다 증가하며 안전율을 동일하게 할 경우 원형PC말뚝보다 말뚝의 수량을 줄일 수 있어 더 경제적이라 할 수 있을 것이다.

• 대한의용생체공학회:의공학회지
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• 제25권4호
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• pp.289-293
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• 2004

본 연구에서는 경사각도가 다른 내, 외측 후족 왯지를 착용하고 보행하는 동안 삼차원 동작분석시스템과 무선가속도측정시스템을 이용하여 무릎관절의 내번토크와 내외측 방향 가속도를 측정하였다. 내번토크와 외측 가속도는 하중수용기와 전유각기에서 각각 양의 절정값을 나타내었다. 하중수용기에 내측 왯지의 경우 내번토크와 외측 가속도가 맨발에 비하여 증가되었으며, 외측 왯지의 경우 내번토크와 외측 가속도값이 감소하였다. (p<0.05). 이러한 변화는 왯지의 경사각이 커질수록 더욱 뚜렷한 상관성을 보였다(p<0.05). 그러나 전유각기에서는 왯지의 방향과 경사에 따른 무릎의 내번토크와 내외측 가속도의 상관성을 확인할 수 없었다. 본 연구의 견과를 통하여 외측 왯지 사용 시 무릎관절의 내번토크가 감소되어 퇴행성 무릎관절염의 치료에 도움을 줄 수 있다. 또한, 보행 중 무릎관절의 내번토크 대신에 외측방향 가속도를 측정함으로써 간단히 왯지의 효과를 결정할 수 있을 것이다.

• Earthquakes and Structures
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• 제18권4호
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• pp.451-466
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• 2020

In this paper, the effect of Engineered Cementitious Composites (ECC) on the lateral strength of a bearing unreinforced Masonry (URM) wall, was experimentally and numerically investigated. Two half scale solid walls were constructed and were tested under quasi-static lateral loading. The first specimen was an un-retrofitted masonry wall (reference wall) while the second one was retrofitted by ECC mortar connected to the wall foundation via steel rebar dowels. The effect of pre-compression level, ECC layer thickness and one or double-side retrofitting on the URM wall lateral strength was numerically investigated. The validation of the numerical model was carried out from the experimental results. The results indicated that the application of ECC layer increases the wall lateral strength and the level of increment depends on the above mentioned parameters. Increasing pre-compression levels and the lack of connection between the ECC layer and the wall foundation reduces the influence of the ECC mortar on the wall lateral strength. In addition, the wall failure mode changes from flexure to the toe-crashing behavior. Furthermore, in the case of ECC layer connected to the wall foundation, the ECC layer thickness and double-side retrofitting showed a significant effect on the wall lateral strength. Finally, a simple method for estimating the lateral strength of retrofitted masonry walls is presented. The results of this method is in good agreement with the numerical results.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.268-271
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• 2007

A sandwich tube is a structured material that has two inner and outer circular tubes and light material between them. In this paper, a sandwich tube with a pyramidal truss core is introduced. Fabrication method and example made by brazing are shown. The behavior of the sandwich tube under lateral loading is predicted by analytical and numerical method. Comparative study between the sandwich and the monocoque tube is performed at a point of view such as strength and weight saving. As a result, proposed tube is appropriate for application to lightweight structural material

• Structural Engineering and Mechanics
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• 제49권2호
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• pp.147-161
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• 2014

In this paper a nonlinear finite element analysis model is established for cold-formed steel zed-section purlins subjected to uplift loading. In the model, the lateral and rotational restraints provided by the sheeting to the purlin are simplified as a lateral rigid restraint imposed at the upper flange-web junction and a rotational spring restraint applied at the mid of the upper flange where the sheeting is fixed. The analyses are performed by considering both geometrical and material nonlinearities. The influences of the rotational spring stiffness and initial geometrical imperfections on the uplift loading capacity of the purlin are investigated numerically. It is found that the rotational spring stiffness has significant influence on the purlin performance. However, the influence of the initial geometric imperfections on the purlin performance is found only in purlins of medium or long length with no or low rotational spring stiffness.

• Geomechanics and Engineering
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• 제3권1호
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• pp.29-43
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• 2011

In this paper a semi-analytical approach is proposed to study the lateral behavior of a piled footing under horizontal loading. As accurate computation of stresses is usually needed at the interface separating the footing (pile) and the soil, this important location should be appropriately modeled as zero-thickness joint element. The piled footing is embedded in elastic soil with either homogeneous modulus or modulus proportional to depth (Gibson's soil). As the pile is the principal element in the piled footing system, a limited parametric study is carried out in order to investigate the influence of footing dimensions and the interface conditions on the lateral behavior of the pile. Hence, the pile behavior is examined through its main governing parameters, namely, the lateral displacement profiles, the bending moments, the shear forces and the soil reactions. The numerical results are presented for Poisson's ratio of 0.2 to represent a large variety of sands and Poisson's ratio of 0.5 to represent undrained clays.

• Tribology and Lubricants
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• 제29권2호
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• pp.91-97
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• 2013

Quantifying the nanoscale force between the atomic force microscopy (AFM) probe of a force-sensing cantilever and the sample is one of the challenges faced by AFM researchers. The normal force calibration is straightforward; however, the lateral force is complicated due to the twisting motion of the cantilever. Force measurement in a liquid environment is often needed for biological applications; however, calibrating the force of the AFM probes for those applications is more difficult owing to the limitations of conventional calibration methods. In this work, an accurate nondestructive lateral force calibration method using multiple pivot loading was proposed for liquid environment. The torque sensitivity at the location of the integrated probe was extrapolated based on accurately measured torque sensitivities across the cantilever width along a few cantilever lengths. The uncertainty of the torque sensitivity at the location of the integrated tip was about 13%, which is significantly smaller than those for other calibration methods in a liquid environment.

• Journal of Electrochemical Science and Technology
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• 제8권4호
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• pp.331-337
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• 2017

A simple strategy is proposed herein for attaining uniform current distribution in direct methanol fuel cells by varying the catalyst loading over the electrode. In order to use the same total catalyst amount for a serpentine flow field, three spatial variation types of catalyst loading were selected: enhancing the cathode catalyst loading (i) near the cathode outlet, (ii) near the cathode inlet, and (iii) near the lateral areas. These variations in catalyst loading are shown to improve the homogeneity of the current distribution, particularly at lower currents and lower air-flow rates. Among these three variations, increased loading near the lateral areas was shown to contribute most to achieving a homogenous current distribution. The mechanism underlying each catalyst loading variation method is different; very high catalyst-loading is shown to decrease the homogeneity of the distribution, which may be caused by water management in the thick catalyst layer thereof.

• Geomechanics and Engineering
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• 제28권6호
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• pp.585-598
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• 2022

The monopile-friction wheel hybrid foundation is an innovative solution for offshore structures which are mainly subjected to large lateral eccentric load induced by winds, waves, and currents during their service life. This paper presents an extensive numerical analysis to investigate the lateral load and moment bearing performances of hybrid foundation, considering various potential influencing factors in sand-overlaying-clay soil deposits, with the complex lateral loads being simplified into a resultant lateral load acting at a certain height above the mudline. Finite element models are generated and validated against experimental data where very good agreements are obtained. The failure mechanisms of hybrid foundations under lateral loading are illustrated to demonstrate the effect of the friction wheel in the hybrid system. Parametric study shows that the load bearing performances of the hybrid foundation is significantly dependent of wheel diameter, pile embedment depth, internal friction angle of sand, loading eccentricity (distance from the load application point to the ground level), and the thickness of upper sandy layer. Simplified empirical formulae is proposed based on the numerical results to predict the corresponding lateral load and moment bearing capacities of the hybrid foundation for design application.

• 한국강구조학회 논문집
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• 제19권6호
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• pp.671-680
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• 2007

본 연구에서는 연속 2-거더교에서 하부 수평브레이싱의 유 무에 따른 하중분배효과를 파악하기 위하여 실제 교량으로부터 1/5 축소 제작된 모형 교량을 이용하여 재하 실험을 수행하였다. 실험 결과에 의하면 편재하된 하중에 대해 수평브레이싱이 설치되면 바닥판과 가로보의 구조적 기능이 향상되어 하중의 분배효과가 증가하는 것으로 나타났다. 한편, 해석모델을 사용하여 수평브레이싱 유 무에 따른 하중분배율을 정량적으로 평가해 본 결과, 수평브레이싱이 미설치된 경우는 대부분 바닥판에 의해 편재하 하중의 21% 정도가 반대측 거더로 전달되었고, 설치된 경우는 가로보와 브레이싱, 그리고 바닥판 모두 하중분배에 기여하여 하중분배효과가 1.7배 정도 증가하는 것으로 나타났다. 이는 수평브레이싱이 설치로 인해 가로보와 바닥판, 그리고 수평브레이싱 부재가 유사폐합단면을 구성하여 시험체의 비틂 강성이 증가되기 때문으로 분석되었다.