• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.127-130
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• 2002

The 2.5 vol% TiNi/6061Al composites were fabricated by permanent mold casting, and its microstructures and tensile test for the cold rolled composites with maximum 50% reduction ratio were investigated. In the case of TiNi fiber with 2mm interval in preform, the interface bonding of fabricated composites were good. EPMA analysis results were found the small amount of Mg, Si segregated interface of diffusion layer. Transverse section of TiNi fiber was decreased with increasing reduction ratio and 40% reduction ratio was observed microcrack from TiNi fiber. And the tensile strength of composites at 38% reduction ratio was 194MPa. In the case of over 38% reduction ratio, the decrease of the tensile strength was due to TiNi fiber rupture by excess working. The fracture mode was appeared brittle fracture with increasing reduction ratio

• International Journal of Railway
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• 제2권4호
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• pp.131-138
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• 2009

Static tensile and fatigue tests were conducted using tensile-shear specimens to evaluate the fatigue strength of a SPCC sheet clinch joint. The maximum tensile strength of the specimen produced at the optimal punching force was 1750 kN. The fatigue endurance limit (=760 N) approached 43% of the maximum tensile load (=1750 N) at a load ratio of 0.1, suggesting that the fatigue limit is approximately half of the value of the maximum tensile strength. The FEM analysis showed that at the fatigue endurance limit, the maximum von-Mises stress of 373 MPa is very close to the ultimate tensile strength of the SPCC sheet (=382 MPa).

• 한국건설순환자원학회논문집
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• 제6권3호
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• pp.160-166
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• 2018

이 연구의 목적은 폴리에틸렌 섬유의 형상비에 따른 알칼리활성 무시멘트 복합재료의 압축강도와 인장거동을 실험적으로 조사하는 것이다. 이를 위하여 섬유의 형상비에 따라 두 가지 배합을 결정하였고, 압축강도를 측정하고 인장실험을 수행하였다. 실험결과 섬유의 형상비에 따른 압축강도의 영향은 거의 나타나지 않은 반면 인장거동은 큰 차이가 발생하였다. 형상비가 높은 섬유를 사용한 배합은 형상비가 낮은 섬유를 사용한 배합에 비하여 강도, 변형성능, 균열개수가 크게 나타났다. 반면에 균열간격과 균열폭은 높은 형상비를 갖는 섬유를 함유한 배합에서 작게 나타났다.

• 터널과지하공간
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• 제23권3호
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• pp.212-218
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• 2013

풍화된 응회암 시험편을 모사하기 위하여 최고 예열온도를 200, 400, 600($^{\circ}C$)로 한 예열시험편을 제작하였다. 각 예열시험편에 대한 실내시험을 통해 비중, 흡수율, 탄성파속도, 일축압축강도, 압열인장강도, 탄성계수, 포아송비, 슬레이크 내구성 지수를 측정하였다. 암석에 열을 가하는 경우 물성의 열화가 발생하는 것으로 나타났으나 예외적으로 슬레이크 내구성 지수는 별로 영향을 받지 않는 것으로 평가되었다. P-파 속도와 일축압축강도, 압열인장강도, 탄성계수, 흡수율 간에는 상당한 상관성이 있는 것으로 해석되었으며, P-파 속도를 알면 일축압축강도, 압열인장강도, 탄성계수, 흡수율을 추정할 수 있는 회귀식을 도출하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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• pp.220-225
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• 1993

This paper is an experimental study on shear capacity of the high strength lightweight reinforced concrete beams with shear-depth ratio between 1.5 and 2.5. Thirteen T & rectangular beams were tested to determine their diagonal cracking and ultimate shear capacity. The major variables are shear span-depth ratio (a/d=1.5, 2.0, 2.5), concrete compressive strength(f'c=210, 24., 270㎏/㎠) and tensile steel ratio( =0.6, 1.2%). Based on results obtained from experiment of high strength lightweight reinforced concrete Beam & normal concrete, the following conclusions were drawn. (1) The shear capacity of high-strength lightweight concrete is less 15% than that of normal concrete under same condition. (2) As the results of Comparing this experimental datas with other various formulas. It is regarded that ACI 318-89 shear strength formula related tensile strength is proper to design formula of shear strength of high-strength lightweight reinforced concrete using lightweight concrete.

• 한국농공학회지
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• 제39권1호
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• pp.83-92
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• 1997

An experimental study of the application of Silica fume for the high strength concrete was conducted. Nine specimens with three different contents of silica fume, 0%, 10%, 20% and with three water-cement ratio 30%, 40%, 50% were tested. Results shows that 10% of silica fume and 30% of water-cement ratio has a maximum strength with 700kg/$cm^2$ of compressive strength and 64kg/$cm^2$ of splitting tensile strength and 100kg/$cm^2$ of flexural strength. Slump value of the tested samples decreases with increasing water-cement ratio and elapsed time of silica fume. Splitting tensile strength$({\sigma}_f)$ and flexural strength $({\sigma}_f)$ and static modulus of elasticity(E) can be correlated with compressive strength $({\sigma}_c)$ from a regression analysis.

• 한국건축시공학회지
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• 제9권1호
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• pp.43-47
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• 2009

The most of waste foundry sands(WFS) have been discarded. It is very urgent for our country to make a study on recycling of WFS. The one of recycling method of WFS is using them as fine aggregate for concrete. This study provided the optimum amount of WFS and flyash when WFS and flyash were used together in concrete. The concrete made with 60% WFS fine aggregate replacement showed higher compressive strength, splitting tensile strength and modulus of elasticity than normal concrete. In the case that the flyash and WFS are replaced together, the compressive strength and splitting tensile strength were improved at flyash replacement ratio $10%{\sim}20%$ and WFS replacement ratio $40%{\sim}60%$. The increase of WFS and flyash replacement led lower air content. While the increase of WFS replacement led lower slump, the increase of flyash replacement led higher slump.

• 한국지반환경공학회 논문집
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• 제4권3호
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• pp.51-59
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• 2003

지오셀 시스템의 사질토 지반에서의 보강효과를 규명하기 위하여 높이 대 폭비(H/W), 상대밀도, 재료의 강도, 복토의 두께를 다르게 하여 모형 재하시험을 수행하였다. 연구 결과 지오셀 시스템은 지오셀의 인장강도보다는 연결부의 강도가 작게 나타나 더 중요한 인자로 판단되었다. 모래의 상대밀도, 재료의 강도와 복토두께가 동일한 경우 모형 지오셀의 극한지지력은 높이 대 폭비(H/W)가 클수록 증가하는 경향을 나타내었으며 복토두께 변화에 따른 지지력비(BCR)는 낮은 상대밀도에서 더 크게 나타났다. 또한 모래의 상대밀도, 높이 대 폭비(H/W)와 복토두께가 동일한 경우 모형 지오셀의 재료의 인장강도가 커짐에 따라 극한지지력은 증가하였으며 인장강도의 영향은 조밀한 모래에서 더 두드러진 것으로 나타났다. 또한 복토층의 두께가 작을수록 지지력비는 큰 값을 나타내었다. 재료의 인장강도가 작은 특별한 경우에 Koerner공식의 적용은 주의가 필요할 것으로 사료된다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1994년도 박판성형기술의 진보
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• pp.11-23
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• 1994

Formability of sheet metals can be evaluated using tensile testing. Easily measured tensile properties such as yield strength, tensile strength, elongation, strain hardening exponent, strain rate sensitivity and plastic strain ratio are important parameters to evaluated the sheet formability. This paper briefly explains how these properties are related to deep drawability and stretchability. The plastic anisotropy of sheet metals is usually attributed to the crystallographic texture. However dislocation distribution may influence the anisotropy.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.579-584
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• 2001

The reinforced concrete(RC) beam is developed cracks because the compression strength of concrete is strong but the tensile strength is weak. The structural strength and stiffness is decreased by reduction of tension resistance capacity of concrete due to the developed cracks. Using the fiber reinforced concrete that is increased the flexural strength and tensile strength at tensile part can enhance the strength and stiffness of concrete structure and decrease the tensile flexural cracks and deflection. Therefore, The reinforced concrete used the fiber reinforced concrete at tensile part ensure the safety and serviceability of the concrete structures. In this study, analytical model of a dual concrete beam that is composed of the normal strength concrete at compression part and the high tensile strength concrete at tensile part is developed by using the equilibrium condition of forces and compatibility condition of strains and is parted into elastic analytical model and ultimate analytical model. Three group of test beam that is formed of one reinforced concrete beam and two dual concrete beams for each steel reinforcement ratio is tested to examine the flexural behavior of dual concrete beams. The comparative study of total nine test beams is shown that the ultimate load of a dual concrete beams relative to the reinforced concrete beams have an increase in approximately 30%. In addition, the initial flexural rigidity, as used here, refer to the slope of load-deflection curves in elastic state is increased and the deflection is decreased.