• Title/Summary/Keyword: Strength Property

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Estimation of Moment Resisting Property for Pin Connection Using Shear Strength of Small Glulam Specimens (집성재 소시험편의 전단강도에 의한 핀접합부의 모멘트 저항성능 예측)

  • Hwang, Kweonhwan;Park, Joosaeng
    • Journal of the Korean Wood Science and Technology
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    • v.36 no.4
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    • pp.58-65
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    • 2008
  • Most connections for the glulam structural members consisted of connector and fastener. The mechanical behaviour of the connection can be occurred by the dowel bearing resistance and wood shear by the fastener. This study aims at the examination of the shear properties for the small specimen with lamination components and for the full-sized pin connection and the moment resisting property for the double shear full-sized pin connection using structural column and beam members. Small specimens including glue line shows greater density and shear strength by the lamination effect than other specimens. It is needed that estimations of double shear property and moment resistance for the pin connections should be adjusted in some degree. For the better and safe estimation of moment resistance strength for the column-beam pin connection, however, the shear strength of small specimens should be deducted by 10%.

Mechanical Property of Cabon Nanofiber/Polypropylene Composites by Melt-mixing Process (압출공정에 의한 탄소나노섬유/폴리프로필렌 복합재료의 기계적 특성)

  • Byeon, Jun-Hyeong;Lee, Sang-Gwan;Eom, Mun-Gwan;Min, Gyeong-Sik;Song, Jae-Eun;Lee, Chang-Hun
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.11a
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    • pp.125-128
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    • 2005
  • The dispersion of carbon nanofiber (CNF) was carried out by solution blending, mechanical mixing, and sonication. CNFs at levels of 5-50% fiber weight content were mixed with polypropylene (PP) powder, and then were melt-mixed using a twin-screw extruder. For the further alignment of fibers, extruded rods were stacked uni-directionally in the mold cavity for the compression molding. For the evaluation of mechanical properties of nanocomposites, tension, in-plane shear, and flexural tests were conducted. CNF/PP composites clearly showed reinforcing effect in the longitudinal direction. The tensile modulus and strength have improved by 100% and 40%, respectively for 50 % fiber weight content, and the flexural modulus and strength have increased by 120% and 25%, respectively for the same fiber weight content. The shear modulus showed 65% increase, but the strength dropped sharply by 40%. However, the property enhancement was not significant due to the poor adhesion between fiber and matrix. In the transverse direction, the tensile, flexural, and shear strength decreased as more fibers were added.

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Structural Effect of Conductive Carbons on the Adhesion and Electrochemical Behavior of LiNi0.4Mn0.4Co0.2O2 Cathode for Lithium Ion Batteries

  • Latifatu, Mohammed;Bon, Chris Yeajoon;Lee, Kwang Se;Hamenu, Louis;Kim, Yong Il;Lee, Yun Jung;Lee, Yong Min;Ko, Jang Myoun
    • Journal of Electrochemical Science and Technology
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    • v.9 no.4
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    • pp.330-338
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    • 2018
  • The adhesion strength as well as the electrochemical properties of $LiNi_{0.4}Mn_{0.4}Co_{0.2}O_2$ electrodes containing various conductive carbons (CC) such as fiber-like carbon, vapor-grown carbon fiber, carbon nanotubes, particle-like carbon, Super P, and Ketjen black is compared. The morphological properties is investigated using scanning electron microscope to reveal the interaction between the different CC and the active material. The surface and interfacial cutting analysis system is also used to measure the adhesion strength between the aluminum current collector and the composite film, and the adhesion strength between the active material and the CC of the electrodes. The results obtained from the measured adhesion strength points to the fact that the structure and the particle size of CC additives have tremendous influence on the binding property of the composite electrodes, and this in turn affects the electrochemical property of the configured electrodes.

An Experimental Study on Shear Behaviour of Reinforced High Strength Concrete Beams (고강도 철근콘크리트 보의 전단거동에 관한 실험적 연구)

  • 곽계환;고갑수;곽경헌
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.38 no.3
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    • pp.58-69
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    • 1996
  • In recent years, the research and development about the new material proceeds rapidly and actively. In building industry, high strength concrete is of interest as a new material. Since the building structure becomes bigger, higher and more specialized, the demand of material and member with high strength expands greatly. Therefore in this experiment, cement complex with high strength was made using the condensed silica fume, a basic experiment was performed on strength property, and optimum-mixture-state was determined for manufacturing a high-strength concrete. Shear behaviour and fracture property of concrete beams with high strength were evaluated. On the whole, in spite of many researches, it is one of the difficult problems that shear fracture of concrete beams has not yet been clearly understood theoretically, and now the shear-design-standard forms in many countries are a formula based on experiment. In this study, the variable of shear behavior experiment was shear-reinforcement-ratio. By analyzing test results and comparing with computation value by ACI code, the basic data was offered on shear design of reinforced concrete beams with high strength. The effect of epoxy repair was also investigated for the beams with cracks due to flexural and shear loading.

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Shear Bonding Strength by the Characteristic of Metal Oxidation on the Surface of Ni-Cr Alloy for Porcelain Fused Metal Crown (금속-도재관용 Ni-Cr 합금의 표면산화물특성에 따른 전단결합강도 관찰)

  • Chung, In-Sung;Kim, Chi-Young
    • Journal of Technologic Dentistry
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    • v.35 no.4
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    • pp.359-364
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    • 2013
  • Purpose: This study was to observe characteristic of metal oxidation and bonding strength according to composition of Ni-Cr alloy for porcelain fused to metal crown. The three kinds of Ni-Cr alloy with different composition ratio of parent metal were observed general properties and chemical properties of each alloy surface and measured the shear bonding strength between ceramic and each alloys. The aim of study was to suggest the material for design of parent metal's composition ratio to development of alloy for porcelain fused to metal crown. Methods: The three kinds of alloy as test specimen was Ni(59wt%)-Cr(24wt%), Ni(67wt.%)-Cr(16wt.%) alloy and Ni(71wt%)-Cr(12wt%)alloy. The oxide on surface was observed by EDX. And the shear test was performed by MTS. Results: The surface property and oxide characteristic analysis of oxide layer, weight percentage of Element O within $Ni_{59}Cr_{24}$ alloy measured 23.03wt%, $Ni_{67}Cr_{16}$ alloy measured 21.13wt% and $Ni_{71}Cr_{12}$ alloy was measured 48.55wt%. And the maximum shear bonding strength was measured 58.02Mpa between $Ni_{59}Cr_{24}$ alloy and vintage halo(H2 group). Conclusion: The surface property and oxide characteristic three kind of Ni-Cr alloy was similar. and shear bonding strength showed the highest bonding strength in H2 specimens.

An Experimental Study on the Characteristics of Compressive Strength of Antiwashout Underwater Concrete with Curing Water (양생수에 따른 수중불분리콘크리트의 압축강도특성에 관한 실험적 연구)

  • 윤재범;고창섭;김명식;장희석
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.135-138
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    • 1999
  • The objective of this study is to investigate the compressive strength property of antiwashout underwater concrete with curing water through experimental researches. Type of casting and curing water(fresh water, sea water) are used as main experimental parameter, additionally a few variables affecting compressive strength property are used ; water-cement ratio (45%, 48%, 50%, 52%, 55%), and unit weight of admixtures (antiwashout underwater agent ; 0.6%, 0.8%, 1.0%, 1.2%, 1.4% of unit weight of water, superplasticizer ; 0.5%, 1.0%, 1.5%, 2.0%, 2.5% of unit weight of cement)) Compressive strength level of antiwashout underwater concrete which was cast and cured in fresh water is higher than other one. Consequently, incremental modulus has to increase when the antiwashout underwater concrete is made use of underwater work from ocean.

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An Experimental Study on Carbonation Resistance of Concrete Depending on Surface Treatment of Lightweight Aggregates (경량골재의 표면처리에 따른 콘크리트의 탄산화 저항성에 관한 실험적 연구)

  • Eom, In-Hyeok;On, Jea-Hoon;Kim, Young-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.11a
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    • pp.89-91
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    • 2012
  • The purpose of this study is to investigate the mechanical property and carbonation resistance of concretes using surface treated lightweight aggregate. In order to evaluate mechanical property and carbonation resistance, slump, compressive strength, and carbonation depth are tested. Slump of concretes using surface treated lightweight aggregate measured 120~125mm, which are lower than slump of NWAC. Compared to compressive strength of NWAC, compressive strength of concretes using surface treated lightweight aggregate showed a level of 82.8~95.9%. In carbonation resistance test, carbonation depth of concretes using surface treated lightweight aggregate measured 10.2~11.3mm, which are lower than carbonation depth of NWAC. As a result, it is found that compressive strength is decreased slightly but carbonation resistance is improved, in case of using surface treated lightweight aggregate.

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Early Estimation of Compressive Strength of Concrete Using Mineral Admixture by Refrigeration Curing Method (냉동양생에 의한 광물질 혼합 콘크리트의 압축강도 추정)

  • Sung , Chan-Yong;Cho , Il-Ho
    • Journal of The Korean Society of Agricultural Engineers
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    • v.46 no.5
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    • pp.55-60
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    • 2004
  • This study was performed to evaluate the early estimation of compressive strength of concrete using mineral admixture by refrigeration curing method. It was a method of early decision for the property of concrete after the curing age 28days through the refrigeration curing at $-18{\pm}3^{\circ}$ for five hours. The test result was fixed connection between the curing age 28days and 31hours by the compressive strength test through the standard curing and refrigeration curing. Accordingly, it can be reduced the mistake of construction work by forecasting the property of concrete through the refrigeration curing.

A Study of Strength Property and Durability on Automotive Front Bumper Guard by Configuration (형상 별 자동차 프런트 범퍼 가드에 대한 강도 특성 및 내구성 연구)

  • Han, Moon-Sik;Cho, Jae-Ung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.3
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    • pp.28-33
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    • 2018
  • The automotive front bumper guard is the most important part of the vehicle for protecting the life of driver when a traffic accident happens. In order to ensure safe driving, this part must possess sufficient strength and durability. This study was carried out with structural and fatigue analyses by designing front bumper guard models. After the lowest value for maximum total deformation and equivalent stress was found through structural analysis and the highest value for fatigue life was found for all three models, it was shown that the type C front bumper guard model was the most suitable for application to a real car. The strength property and durability of the optimum design were determined through this study's results.

A Study on Experimental of Two-spans Beam with Steel Fiber According to Repetitive Shear Stress (반복전단응력에 의한 강섬유 2경간 연속보의 실험적 연구)

  • Kwak, Kae-Hwan;Suk, In-Soo;Cho, Sun-Jung;Park, Jong-Gun
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.181-184
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    • 2002
  • In this research, a basis test on steel fiber concrete's material property was carried out and optimum design as well as material property was examined. In corroboration of it, the compressive strength was compared with the tensile strength and this paper tried to get the initial load of flexural cracking and the ultimate load in the positive-negative moment section through the static test of beam. The addition rate of the steel fiber, 0.75 SFRC specimen was failed at $65{\sim}75%$ of the static ultimate strength and it could be concluded that fatigue strength to two million cycle was around 75.2%.

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