• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1540-1549
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• 2009

Shear properties of geosynthetic/geosynthetic and geosynthetic/soil were evaluated from direct shear tests. The type of geosynthetic is Velcro which is effective for geosynthetic interface and make up for the weakness of sandbag. In this study, the cohesion and the angle of internal friction of each interface was estimated. The test results showed that the cohesion and the angle of internal friction of the geosynthetics depended on the amount of normal stress, the type of the geosynthetics used, and combinations of the geosynthetics and soils. Finally, by comparing the apparent cohesion and the friction angle of the geosynthetics, the applicability to design was identified.

• 소성∙가공
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• 제14권2호
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• pp.133-138
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• 2005

This paper presents a study on defects in pearlite lamella structure of high carbon steel by means of finite-element method(FEM) simulation. High-carbon pearlite steel wire is characterized by its nano-sized microstructure feature of alternation ferrite and cementite. The likely fatigue crack is located on interface of the lamella structure where the maximum amplitude of the longitudinal shear stress and transverse shear stress was calculated during cyclic loading. The FEM is proposed for maximum shear stress from loading of lamella structure, and a method is predicted to analyze the likely fatigue crack generation. It is possible to obtain the important basic data which can be guaranteed in the ductility of high carbon steel wire by using FEM simulation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.93-96
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• 2004

This paper presents a study on defects in pearlite lamella structure of high carbon steel by means of finite-element method(FEM) simulation. High-carbon pearlite steel wire is characterized by its nano-sized microstructure feature of alternation ferrite and cementite. The likely fatigue crack is located on interface of the lamella structure where the maximum amplitude of the longitudinal shear stress and transverse shear stress was calculated during cyclic loading. The FEM is proposed for maximum shear stress from loading of lamella structure, and a method is predicted to analyze the likely fatigue crack generation. It is possible to obtain the important basic data which can be guaranteed in the ductility of high carbon steel wire by using FEM simulation.

• 대한기계학회논문집B
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• 제22권7호
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• pp.992-1000
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• 1998

In the present study the behavior of laminar-wavy film flowing down a vertical plate was studied analytically. The effects of film Reynolds number and interfacial shear stress on the mean film thickness, wave amplitude, wave length, and wave celerity were analysed. The anayltical results on the periodic-wave falling film showed good agreements with experimental data for Re < 100. As the film Reynolds number increased, mean film thickness, wave amplitude, and wave celerity increased, but wave length decreased. Depending on the direction of interfacial shear stress, the shape of wavy interface was disturbed significantly, especially for the intermediate-wave. As the interfacial shear stress increased, for the periodic-wave film, wave amplitude and wave celerity increased, but mean film thickness and wave length decreased.

• International Journal of Automotive Technology
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• 제8권4호
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• pp.483-491
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• 2007

A closed form solution of a composite mechanics system is performed for the investigation of elastic-plastic behavior in order to predict fiber stresses, fiber/matrix interfacial shear stresses, and matrix yielding behavior in short fiber reinforced metal matrix composites. The model is based on a theoretical development that considers the stress concentration between fiber ends and the propagation of matrix plasticity and is compared with the results of a conventional shear lag model as well as a modified shear lag model. For the region of matrix plasticity, slip mechanisms between the fiber and matrix which normally occur at the interface are taken into account for the derivation. Results of predicted stresses for the small-scale yielding as well as the large-scale yielding in the matrix are compared with other theories. The effects of fiber aspect ratio are also evaluated for the internal elastic-plastic stress field. It is found that the incorporation of strong fibers results in substantial improvements in composite strength relative to the fiber/matrix interfacial shear stresses, but can produce earlier matrix yielding because of intensified stress concentration effects. It is also found that the present model can be applied to investigate the stress transfer mechanism between the elastic fiber and the elastic-plastic matrix, such as in short fiber reinforced metal matrix composites.

• 한국지반공학회논문집
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• 제39권4호
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• pp.19-29
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• 2023

본 연구에는 지반-그라우트 인터페이스 거동을 평가하기 위한 직접전단시험 장비를 제작하였으며, 제작된 시험 장비를 통해 풍화토, 풍화토-그라우트 두 종류의 시료에 대해 직접전단시험을 수행하였다. 전단응력-슬립 곡선 평가 결과 풍화토-그라우트의 잔류 전단 강도는 단일 풍화토의 잔류 전단 강도와 유사한 값을 나타냈으며, 풍화토-그라우트 인터페이스의 한계 상태 거동은 풍화토에 의해 결정된다는 것을 확인했다. 그러나, 최대 전단 강도의 경우 풍화토-그라우트 인터페이스에서 매우 크게 증가하는 것으로 나타났다. 최대 전단 강도의 증가율은 느슨한 지반에서 더 크게 발생하는 것으로 나타났으며, 이는 풍화토 입자와 그라우트 입자가 섞여 있는 인터페이스 레이어의 두께가 증가했기 때문으로 보인다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.1091-1096
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• 2001

Generally, in a steel girder and the concrete slab act as a composite structure, the connectors must have adequate strength and stiffness. If there are no horizontal or vertical separations at the interface, the connectors are described as rigid, and complete interaction can be said to exist under these idealized circumstances. In previous study, it was considered that the strength of stud is affected by the stud diameter, height of stud and compressive strength of concrete. The differences between previous study and this study are variables, which are shank diameter of shear connector, the spacing of shear connector, the size of specimen and the row of shear connector. So this paper, as a study on the strength of shear connector with the spacing of shear connector, size of specimen (block-out size), row of shear connector and shank diameter of shear connector resulted from the push-out specimen are conducted with ABAQUS program. It is to investigate the effects of characteristics of these factors. The load-slip relations obtained from the experiments are compared with those of analyses. From these results, the trends of stress are stress estimated and compared with push-out test.

• 한국지반신소재학회논문집
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• 제2권1호
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• pp.39-45
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• 2003

보강토 지반에서 가장 중요한 부분은 보강재와 흙사이의 접촉부분으로서 이 부분의 전단강도 및 전단거동은 보강효과에 직접적인 영향을 미친다. 보강토 지반에서 접촉부분의 전단특성을 얻는 방법으로서 인발시험방법과 직접전단시험방법 등이 있다. 실제 보강토 구조물내에서 보강재와 흙사이에 인발이 되는 부분, 전단이 되는 부분 등이 존재한다. 전단이 되는 경우에도 보강재가 전혀 변형을 하지 않는 경우와 보강재 자체가 변형이 되는 경우 등으로 나눌 수 있다. 본 연구에서는 대형 전단시험기를 이용하여, 부직포/모래, 지오그리드/모래 등의 접촉면을 갖는 2종의 토목섬유를 이용하여, 토목섬유의 인장변형이 허용되는 자유조건과 인장변형이 억제되는 고정조건 등 두가지 방법으로 직접전단시험을 실시하였다. 실험결과 자유조건에 비해 고정조건으로 시험을 행한 경우가 마찰각이 더 컸다. 그리고 전단응력이 피크가 되는 전단변형의 크기는 자유조건의 경우가 더 큰 값을 가졌다. 잔류응력의 경우는 고정법의 경우가 컸지만 잔류응력비는 자유법의 경우가 더 큰 값을 가졌다.

• 마이크로전자및패키징학회지
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• 제7권4호
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• pp.31-35
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• 2000

반도체 칩과 리드프레임을 접착하고 있는 얇은 접착제층에 전단하중이 가해질 때 발생하는 응력상태를 조사하고 있다. 계면 응력상태를 해석하기 위해서 경계요소법이 사용되고 있다. 선형 탄성이론을 적용하여 해석하면, 강체와 접착제의 계면이 자유 경 계면과 만나는 부분에서 $\gamma^{\lambda=1}$(0<1<1) 형태의 응력 특이성이 존재한다. 이러한 특이성으로 인해, 모서리 균열이나 계면 박리가 발생할 수 있다.

• Journal of Mechanical Science and Technology
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• 제15권1호
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• pp.61-65
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• 2001

Using the theory of linear piezoelectricity, the problem of two layered strip with a piezoelectric ceramic bonded to an elastic material containing a finite interface crack is considered. The out-of-plane mechanical and in-plane electrical loadings are simultaneously applied to the strip. Fourier transforms are used to reduce the problem to a pair of dual integral equations, which is then expressed in terms of a Fredholm integral equation of the second kind. The stress intensity factor is determined, and numerical analyses for several materials are performed and discussed.